feat: support workspace-managed SSH repository access

crates/worker-runtime/Cargo.toml

@@ -39,7 +39,7 @@ reqwest = { version = "0.13", optional = true, default-features = false, feature
 ring.workspace = true
 tar.workspace = true
 thiserror = { workspace = true }
-tokio = { workspace = true, features = ["net", "rt", "sync", "time"] }
+tokio = { workspace = true, features = ["net", "process", "rt", "sync", "time"] }
 tracing.workspace = true
 tracing-subscriber.workspace = true
 toml.workspace = true

crates/worker-runtime/src/catalog.rs

@@ -119,9 +119,16 @@ impl std::fmt::Debug for SensitiveString {
 }
 
 #[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
-pub struct RepositorySshMaterializationAccess {
+pub struct RepositorySshCredentialCandidate {
     pub credential_id: String,
     pub credential_revision: u64,
+    #[serde(skip, default)]
+    pub private_key: SensitiveString,
+}
+
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
+pub struct RepositorySshMaterializationAccess {
+    pub credential_candidates: Vec<RepositorySshCredentialCandidate>,
     pub host_trust_id: String,
     pub host_trust_revision: u64,
     pub access: workspace_api::RepositoryAccessMode,
@@ -131,8 +138,6 @@ pub struct RepositorySshMaterializationAccess {
     pub repository_uri: String,
     pub secret_resource: crate::resource::BackendResourceHandle,
     #[serde(skip, default)]
-    pub private_key: SensitiveString,
-    #[serde(skip, default)]
     pub known_hosts_entry: SensitiveString,
 }
 

crates/worker-runtime/src/http_server.rs

@@ -24,6 +24,11 @@ use crate::retention::{
 };
 #[cfg(feature = "ws-server")]
 use crate::runtime::RuntimeSubscriptionRecvError;
+use crate::ssh_host_key_probe::{
+    SSH_HOST_KEY_PROBE_OPERATION, SSH_HOST_KEY_PROBE_PATH, SSH_KEYSCAN_TIMEOUT,
+    SshHostKeyProbeError, SshHostKeyProbeRequest, SshHostKeyProbeResponse,
+    probe_ssh_host_keys_with_program,
+};
 use crate::workspace_issuer::{
     RuntimeVerificationSigner, VerifiedWorkspaceCapability, WORKSPACE_VERIFICATION_ACK_PATH,
     WORKSPACE_VERIFICATION_CHALLENGE_PATH, WORKSPACE_VERIFICATION_OPERATION,
@@ -58,7 +63,6 @@ use serde::{Deserialize, Serialize};
 use std::collections::HashMap;
 use std::fmt;
 use std::net::SocketAddr;
-#[cfg(feature = "fs-store")]
 use std::path::PathBuf;
 use std::sync::{Arc, Mutex};
 use tokio::net::TcpListener;
@@ -181,12 +185,27 @@ fn runtime_http_router_with_optional_auth(
     runtime: Runtime,
     local_token: Option<String>,
     workspace_auth: Option<WorkspaceRuntimeHttpAuth>,
+) -> Router {
+    runtime_http_router_with_auth_and_ssh_keyscan_program(
+        runtime,
+        local_token,
+        workspace_auth,
+        PathBuf::from("ssh-keyscan"),
+    )
+}
+
+fn runtime_http_router_with_auth_and_ssh_keyscan_program(
+    runtime: Runtime,
+    local_token: Option<String>,
+    workspace_auth: Option<WorkspaceRuntimeHttpAuth>,
+    ssh_keyscan_program: PathBuf,
 ) -> Router {
     let state = RuntimeHttpState {
         runtime,
         local_token: local_token.map(Arc::<str>::from),
         workspace_auth: workspace_auth.map(Arc::new),
         workdir_sessions: Arc::new(Mutex::new(HashMap::new())),
+        ssh_keyscan_program: Arc::new(ssh_keyscan_program),
     };
 
     let router = Router::new()
@@ -220,6 +239,10 @@ fn runtime_http_router_with_optional_auth(
             "/v1/working-directories/repository-access",
             post(authorize_working_directory_repository_access),
         )
+        .route(
+            SSH_HOST_KEY_PROBE_PATH,
+            post(probe_repository_ssh_host_keys),
+        )
         .route("/v1/repository-refs/observe", post(observe_repository_ref))
         .route(
             "/v1/working-directories/{working_directory_id}/sessions",
@@ -293,6 +316,7 @@ struct RuntimeHttpState {
     local_token: Option<Arc<str>>,
     workspace_auth: Option<Arc<WorkspaceRuntimeHttpAuth>>,
     workdir_sessions: Arc<Mutex<HashMap<String, RuntimeHttpWorkdirSession>>>,
+    ssh_keyscan_program: Arc<PathBuf>,
 }
 
 #[derive(Clone, Debug)]
@@ -811,6 +835,45 @@ async fn authorize_working_directory_repository_access(
     }))
 }
 
+async fn probe_repository_ssh_host_keys(
+    State(state): State<RuntimeHttpState>,
+    Extension(_auth): Extension<RuntimeAuthContext>,
+    body: Result<Json<SshHostKeyProbeRequest>, JsonRejection>,
+) -> RestResult<SshHostKeyProbeResponse> {
+    let Json(request) = body.map_err(RuntimeHttpRestError::json_rejection)?;
+    let response = probe_ssh_host_keys_with_program(
+        &request,
+        state.ssh_keyscan_program.as_path(),
+        SSH_KEYSCAN_TIMEOUT,
+    )
+    .await
+    .map_err(|error| match error {
+        SshHostKeyProbeError::InvalidHostname | SshHostKeyProbeError::InvalidPort => {
+            RuntimeHttpRestError::new(
+                StatusCode::BAD_REQUEST,
+                "ssh_host_key_probe_invalid_request",
+                error.to_string(),
+            )
+        }
+        SshHostKeyProbeError::Unavailable => RuntimeHttpRestError::new(
+            StatusCode::SERVICE_UNAVAILABLE,
+            "ssh_host_key_probe_unavailable",
+            error.to_string(),
+        ),
+        SshHostKeyProbeError::Timeout => RuntimeHttpRestError::new(
+            StatusCode::GATEWAY_TIMEOUT,
+            "ssh_host_key_probe_timeout",
+            error.to_string(),
+        ),
+        SshHostKeyProbeError::Failed { .. } => RuntimeHttpRestError::new(
+            StatusCode::BAD_GATEWAY,
+            "ssh_host_key_probe_failed",
+            error.to_string(),
+        ),
+    })?;
+    Ok(Json(response))
+}
+
 async fn observe_repository_ref(
     State(state): State<RuntimeHttpState>,
     Extension(auth): Extension<RuntimeAuthContext>,
@@ -2174,10 +2237,11 @@ fn required_runtime_permission(method: &Method, path: &str) -> Option<&'static s
         return Some("workers:create");
     }
     if (path == "/v1/working-directories/repository-access"
-        || path == "/v1/repository-refs/observe")
+        || path == "/v1/repository-refs/observe"
+        || path == SSH_HOST_KEY_PROBE_PATH)
         && *method == Method::POST
     {
-        return Some("workdirs:operate");
+        return Some(SSH_HOST_KEY_PROBE_OPERATION);
     }
     if path.starts_with("/v1/workdir-sessions")
         || (path.starts_with("/v1/working-directories/") && path.ends_with("/sessions"))
@@ -2848,6 +2912,10 @@ mod tests {
             required_runtime_permission(&Method::POST, "/v1/repository-refs/observe"),
             Some("workdirs:operate")
         );
+        assert_eq!(
+            required_runtime_permission(&Method::POST, SSH_HOST_KEY_PROBE_PATH),
+            Some(SSH_HOST_KEY_PROBE_OPERATION)
+        );
         assert_eq!(
             required_runtime_permission(&Method::POST, "/v1/working-directories/wd-1/sessions"),
             Some("workdirs:operate")
@@ -2890,6 +2958,7 @@ mod tests {
                     session: session.clone(),
                 },
             )]))),
+            ssh_keyscan_program: Arc::new(PathBuf::from("ssh-keyscan")),
         };
         let auth = RuntimeAuthContext {
             server_id: "server-a".to_string(),
@@ -3245,6 +3314,112 @@ mod tests {
         assert_eq!(response.status(), StatusCode::OK);
     }
 
+    #[test]
+    fn ssh_probe_uses_workdir_operation_capability() {
+        assert_eq!(
+            required_runtime_permission(&Method::POST, SSH_HOST_KEY_PROBE_PATH),
+            Some(SSH_HOST_KEY_PROBE_OPERATION)
+        );
+        assert_eq!(
+            workspace_runtime_operation(&Method::POST, SSH_HOST_KEY_PROBE_PATH),
+            SSH_HOST_KEY_PROBE_OPERATION
+        );
+    }
+
+    #[tokio::test]
+    async fn ssh_host_key_probe_rejects_invalid_hostname_before_execution() {
+        let token = "local-token";
+        let app = runtime_http_router_with_auth_and_ssh_keyscan_program(
+            Runtime::new_memory(),
+            Some(token.to_string()),
+            None,
+            PathBuf::from("/definitely/missing/ssh-keyscan"),
+        );
+        let response = authed_json_request(
+            app,
+            Method::POST,
+            SSH_HOST_KEY_PROBE_PATH,
+            token,
+            &SshHostKeyProbeRequest {
+                hostname: "-oProxyCommand=malicious".to_string(),
+                port: 22,
+            },
+        )
+        .await;
+
+        assert_eq!(response.status(), StatusCode::BAD_REQUEST);
+        let error: RuntimeHttpErrorResponse = read_json(response).await;
+        assert_eq!(error.error.code, "ssh_host_key_probe_invalid_request");
+    }
+
+    #[cfg(unix)]
+    #[tokio::test]
+    async fn authenticated_ssh_host_key_probe_returns_deduplicated_candidates() {
+        use base64::Engine as _;
+        use std::os::unix::fs::PermissionsExt as _;
+
+        let mut blob = Vec::new();
+        blob.extend_from_slice(&11_u32.to_be_bytes());
+        blob.extend_from_slice(b"ssh-ed25519");
+        blob.extend_from_slice(&32_u32.to_be_bytes());
+        blob.extend_from_slice(&[9_u8; 32]);
+        let key = base64::engine::general_purpose::STANDARD.encode(blob);
+        let temp = tempfile::tempdir().unwrap();
+        let program = temp.path().join("ssh-keyscan");
+        let recorded_arguments = temp.path().join("arguments");
+        std::fs::write(
+            &program,
+            format!(
+                "#!/bin/sh\nprintf '%s\\n' \"$@\" > '{}'\nprintf 'private diagnostic' >&2\nprintf '%s\\n' 'example.test ssh-ed25519 {key}' '[example.test]:2222 ssh-ed25519 {key}'\n",
+                recorded_arguments.display()
+            ),
+        )
+        .unwrap();
+        std::fs::set_permissions(&program, std::fs::Permissions::from_mode(0o700)).unwrap();
+
+        let token = "local-token";
+        let app = runtime_http_router_with_auth_and_ssh_keyscan_program(
+            Runtime::new_memory(),
+            Some(token.to_string()),
+            None,
+            program,
+        );
+        let body = SshHostKeyProbeRequest {
+            hostname: "example.test".to_string(),
+            port: 2222,
+        };
+
+        let unauthenticated = app
+            .clone()
+            .oneshot(
+                Request::builder()
+                    .method(Method::POST)
+                    .uri("/v1/repositories/ssh/probe")
+                    .header(header::CONTENT_TYPE, "application/json")
+                    .body(Body::from(serde_json::to_vec(&body).unwrap()))
+                    .unwrap(),
+            )
+            .await
+            .unwrap();
+        assert_eq!(unauthenticated.status(), StatusCode::UNAUTHORIZED);
+
+        let response =
+            authed_json_request(app, Method::POST, SSH_HOST_KEY_PROBE_PATH, token, &body).await;
+        assert_eq!(response.status(), StatusCode::OK);
+        assert_eq!(
+            std::fs::read_to_string(recorded_arguments).unwrap(),
+            "-T\n5\n-p\n2222\n-t\ned25519\nexample.test\n"
+        );
+        let response: SshHostKeyProbeResponse = read_json(response).await;
+        assert_eq!(response.candidates.len(), 1);
+        assert_eq!(response.candidates[0].algorithm, "ssh-ed25519");
+        assert_eq!(
+            response.candidates[0].public_key,
+            format!("ssh-ed25519 {key}")
+        );
+        assert!(response.candidates[0].fingerprint.starts_with("SHA256:"));
+    }
+
     #[tokio::test]
     async fn runtime_errors_use_typed_rest_error_shape() {
         let token = "local-token";

crates/worker-runtime/src/lib.rs

@@ -25,6 +25,7 @@ pub mod resource;
 #[cfg(feature = "fs-store")]
 pub mod retention;
 mod runtime;
+pub mod ssh_host_key_probe;
 pub mod worker_backend;
 pub mod worker_source;
 pub mod working_directory;

crates/worker-runtime/src/main.rs

@@ -30,8 +30,8 @@ use worker_runtime::workspace_issuer::{
     FileWorkspaceClaimReplayProtection, FileWorkspaceRuntimeVerificationAuthority,
     MAX_WORKSPACE_ISSUER_TRUST_RECORDS, RuntimeVerificationSigner, WorkspaceCapabilityVerifier,
     WorkspaceIssuerTrustError, WorkspaceIssuerTrustMutation, WorkspaceIssuerTrustRecord,
-    add_workspace_issuer_trust, replace_workspace_issuer_trust, revoke_workspace_issuer_trust,
+    WorkspaceIssuerTrustState, add_workspace_issuer_trust, replace_workspace_issuer_trust,
-    validate_workspace_issuer_trust_records,
+    revoke_workspace_issuer_trust, validate_workspace_issuer_trust_records,
 };
 use worker_runtime::{Runtime, RuntimeOptions};
 
@@ -236,6 +236,33 @@ fn build_runtime(config: &ProcessConfig) -> Result<Runtime, ProcessError> {
         factory = factory.with_resource_client(client.clone());
         backend_resource_client = Some(client);
     }
+    let mut workspace_backend_resource_clients: Vec<(
+        String,
+        Arc<dyn worker_runtime::resource::BackendResourceClient>,
+    )> = Vec::new();
+    if config.backend_resource_endpoint.is_none()
+        && let Some(identity) = runtime_auth.identity.as_ref()
+    {
+        for workspace_issuer in runtime_auth
+            .workspace_issuers
+            .iter()
+            .filter(|issuer| issuer.state == WorkspaceIssuerTrustState::Active)
+        {
+            let endpoint = workspace_backend_resource_endpoint(
+                &workspace_issuer.backend_url,
+                &workspace_issuer.workspace_id,
+            );
+            let client = Arc::new(
+                worker_runtime::resource::HttpBackendResourceClient::new(
+                    endpoint,
+                    config.backend_resource_token.clone(),
+                )
+                .with_runtime_request_source(identity, workspace_issuer.backend_url.clone()),
+            );
+            workspace_backend_resource_clients
+                .push((workspace_issuer.workspace_id.clone(), client));
+        }
+    }
     let backend = Arc::new(
         WorkerRuntimeExecutionBackend::new(factory)
             .map_err(ProcessError::WorkerAdapter)?
@@ -267,14 +294,31 @@ fn build_runtime(config: &ProcessConfig) -> Result<Runtime, ProcessError> {
             ));
         }
     };
+    if let Some(identity) = runtime_auth.identity.as_ref() {
+        runtime
+            .bind_runtime_identity(&identity.identity_id)
+            .map_err(ProcessError::Runtime)?;
+    }
     if let Some(client) = backend_resource_client {
         runtime
             .install_backend_resource_client(client)
             .map_err(ProcessError::Runtime)?;
     }
+    for (workspace_id, client) in workspace_backend_resource_clients {
+        runtime
+            .install_workspace_backend_resource_client(workspace_id, client)
+            .map_err(ProcessError::Runtime)?;
+    }
     Ok(runtime)
 }
 
+fn workspace_backend_resource_endpoint(backend_url: &str, workspace_id: &str) -> String {
+    format!(
+        "{}/api/runtime/v1/workspaces/{workspace_id}/resources/fetch",
+        backend_url.trim_end_matches('/'),
+    )
+}
+
 fn runtime_options_from_http(config: &RuntimeHttpServerConfig) -> RuntimeOptions {
     RuntimeOptions {
         display_name: config.display_name.clone(),
@@ -1521,6 +1565,42 @@ mod tests {
         assert_eq!(error, "unknown auth command `trust-server`");
     }
 
+    #[test]
+    fn runtime_startup_binds_auth_identity_before_resource_use() {
+        let temp = tempfile::tempdir().unwrap();
+        let mut config = ProcessConfig {
+            fs_root: Some(temp.path().to_path_buf()),
+            ..ProcessConfig::default().unwrap()
+        };
+        config.http.store = RuntimeHttpStoreSelection::Memory;
+        let identity = RuntimeIdentityMaterial::generate("runtime-startup").unwrap();
+        write_runtime_auth_file(
+            &runtime_auth_path(&config),
+            &RuntimeAuthFile {
+                identity: Some(identity),
+                workspace_issuers: Vec::new(),
+            },
+        )
+        .unwrap();
+
+        let runtime = build_runtime(&config).unwrap();
+
+        runtime.bind_runtime_identity("runtime-startup").unwrap();
+        assert!(runtime.bind_runtime_identity("other-runtime").is_err());
+    }
+
+    #[test]
+    fn workspace_resource_endpoints_are_derived_per_issuer() {
+        assert_eq!(
+            workspace_backend_resource_endpoint("https://backend.example/", "workspace-a"),
+            "https://backend.example/api/runtime/v1/workspaces/workspace-a/resources/fetch"
+        );
+        assert_ne!(
+            workspace_backend_resource_endpoint("https://backend.example", "workspace-a"),
+            workspace_backend_resource_endpoint("https://backend.example", "workspace-b")
+        );
+    }
+
     #[test]
     fn no_store_disables_runtime_catalog_persistence() {
         let config = parse_args(["--no-store"]).unwrap().unwrap();

crates/worker-runtime/src/resource.rs

@@ -13,16 +13,41 @@ pub const REPOSITORY_SSH_ACCESS_CONTENT_TYPE: &str =
     "application/vnd.yoi.repository-ssh-access+json";
 pub const DEFAULT_PROFILE_SOURCE_ARCHIVE_MAX_BYTES: u64 = 2 * 1024 * 1024;
 pub const DEFAULT_REPOSITORY_SSH_ACCESS_MAX_BYTES: u64 = 64 * 1024;
+pub const DEFAULT_BACKEND_RESOURCE_FETCH_TIMEOUT: std::time::Duration =
+    std::time::Duration::from_secs(15);
+
+#[derive(Clone, Serialize, Deserialize)]
+pub struct RepositorySshAccessSecretCandidate {
+    pub credential_id: String,
+    pub credential_revision: u64,
+    pub private_key: String,
+}
+
+impl Drop for RepositorySshAccessSecretCandidate {
+    fn drop(&mut self) {
+        zeroize::Zeroize::zeroize(&mut self.private_key);
+    }
+}
+
+impl std::fmt::Debug for RepositorySshAccessSecretCandidate {
+    fn fmt(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        formatter
+            .debug_struct("RepositorySshAccessSecretCandidate")
+            .field("credential_id", &self.credential_id)
+            .field("credential_revision", &self.credential_revision)
+            .field("private_key", &"[REDACTED]")
+            .finish()
+    }
+}
 
 #[derive(Clone, Serialize, Deserialize)]
 pub struct RepositorySshAccessSecret {
-    pub private_key: String,
+    pub credential_candidates: Vec<RepositorySshAccessSecretCandidate>,
     pub known_hosts_entry: String,
 }
 
 impl Drop for RepositorySshAccessSecret {
     fn drop(&mut self) {
-        zeroize::Zeroize::zeroize(&mut self.private_key);
         zeroize::Zeroize::zeroize(&mut self.known_hosts_entry);
     }
 }
@@ -31,7 +56,7 @@ impl std::fmt::Debug for RepositorySshAccessSecret {
     fn fmt(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         formatter
             .debug_struct("RepositorySshAccessSecret")
-            .field("private_key", &"[REDACTED]")
+            .field("credential_candidates", &self.credential_candidates)
             .field("known_hosts_entry", &"[REDACTED]")
             .finish()
     }
@@ -142,6 +167,8 @@ pub enum BackendResourceError {
     Oversized { max_bytes: u64, actual_bytes: u64 },
     #[error("backend resource content type mismatch: expected {expected}, got {actual}")]
     ContentTypeMismatch { expected: String, actual: String },
+    #[error("backend resource fetch timed out")]
+    Timeout,
     #[error("backend resource transport failed: {message}")]
     Transport { message: String },
     #[error("backend resource response is invalid: {message}")]
@@ -163,6 +190,7 @@ pub struct HttpBackendResourceClient {
     bearer_token: Option<String>,
     request_source_signer: Option<RuntimeRequestSourceSigner>,
     request_source_audience: Option<String>,
+    request_timeout: std::time::Duration,
     client: reqwest::Client,
 }
 
@@ -174,10 +202,16 @@ impl HttpBackendResourceClient {
             bearer_token,
             request_source_signer: None,
             request_source_audience: None,
+            request_timeout: DEFAULT_BACKEND_RESOURCE_FETCH_TIMEOUT,
             client: reqwest::Client::new(),
         }
     }
 
+    pub fn with_request_timeout(mut self, timeout: std::time::Duration) -> Self {
+        self.request_timeout = timeout;
+        self
+    }
+
     pub fn with_runtime_request_source(
         mut self,
         identity: &RuntimeIdentityMaterial,
@@ -209,6 +243,7 @@ impl BackendResourceClient for HttpBackendResourceClient {
         let mut builder = self
             .client
             .post(endpoint.clone())
+            .timeout(self.request_timeout)
             .header(reqwest::header::CONTENT_TYPE, "application/json")
             .body(body.clone());
         if let Some(signer) = self.request_source_signer.as_ref() {
@@ -239,11 +274,14 @@ impl BackendResourceClient for HttpBackendResourceClient {
         } else {
             builder
         };
-        let response = builder
+        let response = builder.send().await.map_err(|error| {
-            .send()
+            if error.is_timeout() {
-            .await
+                BackendResourceError::Timeout
-            .map_err(|err| BackendResourceError::Transport {
+            } else {
-                message: err.to_string(),
+                BackendResourceError::Transport {
+                    message: error.to_string(),
+                }
+            }
         })?;
         if response.status().is_success() {
             response
@@ -382,6 +420,54 @@ mod tests {
         }
     }
 
+    #[cfg(feature = "http-server")]
+    #[tokio::test]
+    async fn http_backend_resource_fetch_has_a_bounded_timeout() {
+        let listener = tokio::net::TcpListener::bind("127.0.0.1:0").await.unwrap();
+        let address = listener.local_addr().unwrap();
+        let server = tokio::spawn(async move {
+            let (stream, _) = listener.accept().await.unwrap();
+            futures::future::pending::<()>().await;
+            drop(stream);
+        });
+        let base_url = format!("http://{address}");
+        let identity = RuntimeIdentityMaterial::generate("runtime-test").unwrap();
+        let handle = handle_for(b"archive-bytes");
+        let client = HttpBackendResourceClient::new(format!("{base_url}/fetch"), None)
+            .with_request_timeout(std::time::Duration::from_millis(25))
+            .with_runtime_request_source(&identity, base_url);
+
+        let error = client
+            .fetch_resource(BackendResourceFetchRequest {
+                audit_correlation_id: handle.audit_correlation_id.clone(),
+                handle,
+                runtime_id: "runtime-test".to_string(),
+                worker_id: None,
+            })
+            .await
+            .unwrap_err();
+
+        server.abort();
+        assert_eq!(error, BackendResourceError::Timeout);
+    }
+
+    #[test]
+    fn repository_ssh_access_secret_debug_redacts_all_secret_values() {
+        let secret = RepositorySshAccessSecret {
+            credential_candidates: vec![RepositorySshAccessSecretCandidate {
+                credential_id: "credential-1".to_string(),
+                credential_revision: 2,
+                private_key: "PRIVATE KEY secret bytes".to_string(),
+            }],
+            known_hosts_entry: "host key secret bytes".to_string(),
+        };
+
+        let debug = format!("{secret:?}");
+        assert!(debug.contains("credential-1"));
+        assert!(!debug.contains("secret bytes"));
+        assert_eq!(debug.matches("[REDACTED]").count(), 2);
+    }
+
     #[test]
     fn response_verification_detects_digest_mismatch() {
         let bytes = b"archive-bytes";

crates/worker-runtime/src/runtime.rs

@@ -189,6 +189,23 @@ impl Runtime {
         Ok(())
     }
 
+    pub fn install_workspace_backend_resource_client(
+        &self,
+        workspace_id: impl Into<String>,
+        client: Arc<dyn BackendResourceClient>,
+    ) -> Result<(), RuntimeError> {
+        let workspace_id = workspace_id.into();
+        if workspace_id.trim().is_empty() {
+            return Err(RuntimeError::InvalidRequest(
+                "Backend resource client Workspace id is empty".to_string(),
+            ));
+        }
+        self.lock()?
+            .workspace_backend_resource_clients
+            .insert(workspace_id, BackendResourceClientRef(client));
+        Ok(())
+    }
+
     /// Create or restore a filesystem-backed Runtime.
     ///
     /// The store is scoped by `options.root`; if the directory already exists,
@@ -439,26 +456,51 @@ impl Runtime {
         &self,
         ssh: &mut crate::catalog::RepositorySshMaterializationAccess,
     ) -> Result<(), RuntimeError> {
-        if !ssh.private_key.expose().is_empty() && !ssh.known_hosts_entry.expose().is_empty() {
+        if ssh.credential_candidates.is_empty() {
+            return Err(RuntimeError::InvalidRequest(
+                "Repository SSH access requires at least one credential candidate".to_string(),
+            ));
+        }
+        if ssh
+            .credential_candidates
+            .iter()
+            .all(|candidate| !candidate.private_key.expose().is_empty())
+            && !ssh.known_hosts_entry.expose().is_empty()
+        {
             return Ok(());
         }
         let (client, runtime_id) = {
             let state = self.lock()?;
-            let client = state.backend_resource_client.clone().ok_or_else(|| {
+            let client = state
-                RuntimeError::InvalidRequest(
+                .workspace_backend_resource_clients
-                    "Backend Repository access resource client is unavailable".to_string(),
+                .get(&ssh.secret_resource.workspace_id)
-                )
+                .cloned()
+                .or_else(|| state.backend_resource_client.clone())
+                .ok_or_else(|| {
+                    RuntimeError::InvalidRequest(format!(
+                        "Backend Repository access resource client is unavailable for Workspace `{}`",
+                        ssh.secret_resource.workspace_id
+                    ))
                 })?;
             let runtime_id = state.runtime_identity.clone().ok_or_else(|| {
                 RuntimeError::InvalidRequest("Runtime identity is unavailable".to_string())
             })?;
             (client, runtime_id)
         };
+        tracing::info!(
+            target: "yoi::repository_access",
+            event = "repository_access_resource_fetch_started",
+            workspace_id = %ssh.secret_resource.workspace_id,
+            resource_id = %ssh.secret_resource.resource_id,
+            runtime_id = %runtime_id,
+            credential_candidate_count = ssh.credential_candidates.len(),
+            "fetching Repository SSH access resource from Workspace Backend"
+        );
         let mut response = client
             .0
             .fetch_resource(BackendResourceFetchRequest {
                 handle: ssh.secret_resource.clone(),
-                runtime_id,
+                runtime_id: runtime_id.clone(),
                 worker_id: None,
                 audit_correlation_id: ssh.secret_resource.audit_correlation_id.clone(),
             })
@@ -481,10 +523,40 @@ impl Runtime {
                 "Backend Repository SSH access resource payload was invalid".to_string(),
             )
         })?;
-        ssh.private_key =
+        if secret.credential_candidates.len() != ssh.credential_candidates.len()
+            || secret
+                .credential_candidates
+                .iter()
+                .zip(&ssh.credential_candidates)
+                .any(|(secret, metadata)| {
+                    secret.credential_id != metadata.credential_id
+                        || secret.credential_revision != metadata.credential_revision
+                })
+        {
+            return Err(RuntimeError::InvalidRequest(
+                "Backend Repository SSH access resource credential metadata was invalid"
+                    .to_string(),
+            ));
+        }
+        for (candidate, secret) in ssh
+            .credential_candidates
+            .iter_mut()
+            .zip(&mut secret.credential_candidates)
+        {
+            candidate.private_key =
                 crate::catalog::SensitiveString::new(std::mem::take(&mut secret.private_key));
+        }
         ssh.known_hosts_entry =
             crate::catalog::SensitiveString::new(std::mem::take(&mut secret.known_hosts_entry));
+        tracing::info!(
+            target: "yoi::repository_access",
+            event = "repository_access_resource_fetch_succeeded",
+            workspace_id = %ssh.secret_resource.workspace_id,
+            resource_id = %ssh.secret_resource.resource_id,
+            runtime_id = %runtime_id,
+            credential_candidate_count = ssh.credential_candidates.len(),
+            "fetched Repository SSH access resource from Workspace Backend"
+        );
         Ok(())
     }
 
@@ -492,10 +564,22 @@ impl Runtime {
         &self,
         mut request: WorkingDirectoryRepositoryAccessRequest,
     ) -> Result<(), RuntimeError> {
+        let materialization_runtime_id = request.materialization.runtime_id.clone();
         let ssh = request.materialization.ssh.as_mut().ok_or_else(|| {
             RuntimeError::InvalidRequest("Repository SSH access metadata is missing".to_string())
         })?;
-        self.resolve_repository_access_resource(ssh).await?;
+        if let Err(error) = self.resolve_repository_access_resource(ssh).await {
+            tracing::warn!(
+                target: "yoi::repository_access",
+                event = "repository_access_resource_fetch_failed",
+                workspace_id = %ssh.secret_resource.workspace_id,
+                resource_id = %ssh.secret_resource.resource_id,
+                runtime_id = %materialization_runtime_id,
+                error = %error,
+                "failed to fetch Repository SSH access resource from Workspace Backend"
+            );
+            return Err(error);
+        }
         self.authorize_working_directory_repository_access(request)
     }
 
@@ -2428,6 +2512,7 @@ struct RuntimeState {
     status: RuntimeStatus,
     execution_backend: Option<WorkerExecutionBackendRef>,
     backend_resource_client: Option<BackendResourceClientRef>,
+    workspace_backend_resource_clients: BTreeMap<String, BackendResourceClientRef>,
     #[cfg(feature = "fs-store")]
     next_diagnostic_id: u64,
     workers: BTreeMap<WorkerId, WorkerRecord>,
@@ -2458,6 +2543,7 @@ impl RuntimeState {
             status: RuntimeStatus::Running,
             execution_backend: None,
             backend_resource_client: None,
+            workspace_backend_resource_clients: BTreeMap::new(),
             #[cfg(feature = "fs-store")]
             next_diagnostic_id: 1,
             workers: BTreeMap::new(),
@@ -2489,6 +2575,7 @@ impl RuntimeState {
             status: RuntimeStatus::Running,
             execution_backend: None,
             backend_resource_client: None,
+            workspace_backend_resource_clients: BTreeMap::new(),
             #[cfg(feature = "fs-store")]
             next_diagnostic_id: 1,
             workers: BTreeMap::new(),
@@ -2552,6 +2639,7 @@ impl RuntimeState {
             status: persisted.status,
             execution_backend: None,
             backend_resource_client: None,
+            workspace_backend_resource_clients: BTreeMap::new(),
             next_diagnostic_id,
             workers,
             config_bundles: BTreeMap::new(),
@@ -3344,6 +3432,10 @@ fn repository_resource_error(error: BackendResourceError) -> RuntimeError {
             "repository_access_credential_unavailable",
             "Repository access credential lease is unavailable or already consumed",
         ),
+        BackendResourceError::Timeout => (
+            "repository_access_resource_fetch_timeout",
+            "Timed out while fetching Repository SSH access from Workspace Backend",
+        ),
         BackendResourceError::Transport { .. } => (
             "repository_access_provider_unavailable",
             "Repository access credential provider is unavailable",
@@ -3615,8 +3707,9 @@ mod tests {
     use super::*;
     use crate::catalog::{
         ConfigBundleRef, MaterializerKind, ProfileSelector, RepositoryMaterializationContext,
-        RepositorySshMaterializationAccess, SensitiveString, WorkingDirectoryClaim,
+        RepositorySshCredentialCandidate, RepositorySshMaterializationAccess, SensitiveString,
-        WorkingDirectoryRepository, WorkingDirectoryRequest, WorkspaceApiRef,
+        WorkingDirectoryClaim, WorkingDirectoryRepository, WorkingDirectoryRequest,
+        WorkspaceApiRef,
     };
     use crate::config_bundle::{
         ConfigBundle, ConfigBundleMetadata, ConfigBundleProvenance, ConfigDeclaration,
@@ -3670,6 +3763,10 @@ mod tests {
                 BackendResourceError::MissingResource,
                 "repository_access_credential_unavailable",
             ),
+            (
+                BackendResourceError::Timeout,
+                "repository_access_resource_fetch_timeout",
+            ),
             (
                 BackendResourceError::Unauthorized {
                     message: "denied".to_string(),
@@ -3933,8 +4030,11 @@ mod tests {
                 config_projection_digest: "sha256:projection".to_string(),
                 cache_generation: 0,
                 ssh: Some(RepositorySshMaterializationAccess {
+                    credential_candidates: vec![RepositorySshCredentialCandidate {
                         credential_id: "credential-1".to_string(),
                         credential_revision: 1,
+                        private_key: SensitiveString::new("private-key-bytes"),
+                    }],
                     host_trust_id: "host-trust-1".to_string(),
                     host_trust_revision: 1,
                     access: workspace_api::RepositoryAccessMode::ReadOnly,
@@ -3943,7 +4043,6 @@ mod tests {
                     repository_source_fingerprint: "sha256:source".to_string(),
                     repository_uri: "ssh://git@example.test/repo.git".to_string(),
                     secret_resource: repository_resource_handle(),
-                    private_key: SensitiveString::new("private-key-bytes"),
                     known_hosts_entry: SensitiveString::new("known-hosts-entry"),
                 }),
             }),
@@ -4003,20 +4102,35 @@ mod tests {
         runtime.bind_runtime_identity("runtime-1").unwrap();
         let handle = repository_resource_handle();
         runtime
-            .install_backend_resource_client(Arc::new(TestRepositoryResourceClient {
+            .install_workspace_backend_resource_client(
+                "workspace-1",
+                Arc::new(TestRepositoryResourceClient {
                     response: Mutex::new(Some(crate::resource::BackendResourceFetchResponse {
                         kind: crate::resource::BackendResourceKind::RepositorySshAccess,
                         resource_id: handle.resource_id.clone(),
                         digest: handle.digest.clone(),
-                    content_type: crate::resource::REPOSITORY_SSH_ACCESS_CONTENT_TYPE.to_string(),
+                        content_type: crate::resource::REPOSITORY_SSH_ACCESS_CONTENT_TYPE
+                            .to_string(),
                         bytes: serde_json::to_vec(&RepositorySshAccessSecret {
-                        private_key: "private-key-bytes".to_string(),
+                            credential_candidates: vec![
+                                crate::resource::RepositorySshAccessSecretCandidate {
+                                    credential_id: "credential-1".to_string(),
+                                    credential_revision: 1,
+                                    private_key: "private-key-bytes-1".to_string(),
+                                },
+                                crate::resource::RepositorySshAccessSecretCandidate {
+                                    credential_id: "credential-2".to_string(),
+                                    credential_revision: 3,
+                                    private_key: "private-key-bytes-2".to_string(),
+                                },
+                            ],
                             known_hosts_entry: "known-hosts-entry".to_string(),
                         })
                         .unwrap(),
                         audit_correlation_id: handle.audit_correlation_id.clone(),
                     })),
-            }))
+                }),
+            )
             .unwrap();
         let request = WorkingDirectoryRepositoryAccessRequest {
             working_directory_id: "working-directory-1".to_string(),
@@ -4028,8 +4142,18 @@ mod tests {
                 config_projection_digest: "sha256:projection".to_string(),
                 cache_generation: 0,
                 ssh: Some(RepositorySshMaterializationAccess {
+                    credential_candidates: vec![
+                        RepositorySshCredentialCandidate {
                             credential_id: "credential-1".to_string(),
                             credential_revision: 1,
+                            private_key: SensitiveString::default(),
+                        },
+                        RepositorySshCredentialCandidate {
+                            credential_id: "credential-2".to_string(),
+                            credential_revision: 3,
+                            private_key: SensitiveString::default(),
+                        },
+                    ],
                     host_trust_id: "host-trust-1".to_string(),
                     host_trust_revision: 1,
                     access: workspace_api::RepositoryAccessMode::ReadOnly,
@@ -4038,7 +4162,6 @@ mod tests {
                     repository_source_fingerprint: "sha256:source".to_string(),
                     repository_uri: "ssh://git@example.test/repo.git".to_string(),
                     secret_resource: handle,
-                    private_key: SensitiveString::default(),
                     known_hosts_entry: SensitiveString::default(),
                 }),
             },
@@ -4059,7 +4182,23 @@ mod tests {
         let accesses = backend.repository_accesses.lock().unwrap();
         assert_eq!(accesses.len(), 1);
         let access = accesses[0].materialization.ssh.as_ref().unwrap();
-        assert_eq!(access.private_key.expose(), "private-key-bytes");
+        assert_eq!(access.credential_candidates.len(), 2);
+        assert_eq!(
+            access.credential_candidates[0].credential_id,
+            "credential-1"
+        );
+        assert_eq!(
+            access.credential_candidates[1].credential_id,
+            "credential-2"
+        );
+        assert_eq!(
+            access.credential_candidates[0].private_key.expose(),
+            "private-key-bytes-1"
+        );
+        assert_eq!(
+            access.credential_candidates[1].private_key.expose(),
+            "private-key-bytes-2"
+        );
         assert_eq!(access.known_hosts_entry.expose(), "known-hosts-entry");
     }
 
@@ -4072,20 +4211,35 @@ mod tests {
         runtime.bind_runtime_identity("runtime-1").unwrap();
         let handle = repository_resource_handle();
         runtime
-            .install_backend_resource_client(Arc::new(TestRepositoryResourceClient {
+            .install_workspace_backend_resource_client(
+                "workspace-1",
+                Arc::new(TestRepositoryResourceClient {
                     response: Mutex::new(Some(crate::resource::BackendResourceFetchResponse {
                         kind: crate::resource::BackendResourceKind::RepositorySshAccess,
                         resource_id: handle.resource_id.clone(),
                         digest: handle.digest.clone(),
-                    content_type: crate::resource::REPOSITORY_SSH_ACCESS_CONTENT_TYPE.to_string(),
+                        content_type: crate::resource::REPOSITORY_SSH_ACCESS_CONTENT_TYPE
+                            .to_string(),
                         bytes: serde_json::to_vec(&RepositorySshAccessSecret {
-                        private_key: "create-private-key-bytes".to_string(),
+                            credential_candidates: vec![
+                                crate::resource::RepositorySshAccessSecretCandidate {
+                                    credential_id: "credential-1".to_string(),
+                                    credential_revision: 1,
+                                    private_key: "create-private-key-bytes-1".to_string(),
+                                },
+                                crate::resource::RepositorySshAccessSecretCandidate {
+                                    credential_id: "credential-2".to_string(),
+                                    credential_revision: 3,
+                                    private_key: "create-private-key-bytes-2".to_string(),
+                                },
+                            ],
                             known_hosts_entry: "create-known-hosts-entry".to_string(),
                         })
                         .unwrap(),
                         audit_correlation_id: handle.audit_correlation_id.clone(),
                     })),
-            }))
+                }),
+            )
             .unwrap();
         let request = WorkingDirectoryRequest {
             repository: WorkingDirectoryRepository {
@@ -4109,8 +4263,18 @@ mod tests {
                 config_projection_digest: "sha256:projection".to_string(),
                 cache_generation: 0,
                 ssh: Some(RepositorySshMaterializationAccess {
+                    credential_candidates: vec![
+                        RepositorySshCredentialCandidate {
                             credential_id: "credential-1".to_string(),
                             credential_revision: 1,
+                            private_key: SensitiveString::default(),
+                        },
+                        RepositorySshCredentialCandidate {
+                            credential_id: "credential-2".to_string(),
+                            credential_revision: 3,
+                            private_key: SensitiveString::default(),
+                        },
+                    ],
                     host_trust_id: "host-trust-1".to_string(),
                     host_trust_revision: 1,
                     access: workspace_api::RepositoryAccessMode::ReadOnly,
@@ -4119,7 +4283,6 @@ mod tests {
                     repository_source_fingerprint: "sha256:source".to_string(),
                     repository_uri: "ssh://git@example.test/repo.git".to_string(),
                     secret_resource: handle,
-                    private_key: SensitiveString::default(),
                     known_hosts_entry: SensitiveString::default(),
                 }),
             }),
@@ -4138,7 +4301,14 @@ mod tests {
             .as_ref()
             .and_then(|materialization| materialization.ssh.as_ref())
             .unwrap();
-        assert_eq!(access.private_key.expose(), "create-private-key-bytes");
+        assert_eq!(
+            access.credential_candidates[0].private_key.expose(),
+            "create-private-key-bytes-1"
+        );
+        assert_eq!(
+            access.credential_candidates[1].private_key.expose(),
+            "create-private-key-bytes-2"
+        );
         assert_eq!(
             access.known_hosts_entry.expose(),
             "create-known-hosts-entry"

crates/worker-runtime/src/ssh_host_key_probe.rs

@@ -0,0 +1,368 @@
+//! Side-effect-free SSH host key discovery for Repository trust enrollment.
+//!
+//! Probing only observes public host keys. It does not persist trust, use clone
+//! credentials, or authenticate to the target host.
+
+use base64::Engine as _;
+use base64::engine::general_purpose::{STANDARD, STANDARD_NO_PAD};
+use serde::{Deserialize, Serialize};
+use sha2::{Digest, Sha256};
+use std::collections::BTreeSet;
+use std::net::IpAddr;
+use std::path::Path;
+use std::process::Stdio;
+use std::time::Duration;
+use tokio::process::Command;
+
+pub const SSH_HOST_KEY_PROBE_PATH: &str = "/v1/repositories/ssh/probe";
+pub const SSH_HOST_KEY_PROBE_OPERATION: &str = "workdirs:operate";
+pub(crate) const SSH_KEYSCAN_TIMEOUT: Duration = Duration::from_secs(10);
+const SSH_KEYSCAN_CONNECT_TIMEOUT_SECONDS: &str = "5";
+const MAX_SSH_KEYSCAN_OUTPUT_BYTES: usize = 64 * 1024;
+const MAX_PROBE_CANDIDATES: usize = 32;
+const MAX_DIAGNOSTIC_BYTES: usize = 256;
+
+/// `POST /v1/repositories/ssh/probe` request.
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(deny_unknown_fields)]
+pub struct SshHostKeyProbeRequest {
+    pub hostname: String,
+    pub port: u16,
+}
+
+/// One public host key observed by an SSH host key probe.
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(deny_unknown_fields)]
+pub struct SshHostKeyCandidate {
+    /// Canonical OpenSSH public key text (`algorithm base64-key`), without a host prefix.
+    pub public_key: String,
+    /// OpenSSH public key algorithm name.
+    pub algorithm: String,
+    /// OpenSSH SHA-256 fingerprint (`SHA256:base64-digest`).
+    pub fingerprint: String,
+}
+
+/// `POST /v1/repositories/ssh/probe` response.
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(deny_unknown_fields)]
+pub struct SshHostKeyProbeResponse {
+    pub candidates: Vec<SshHostKeyCandidate>,
+}
+
+#[derive(Clone, Debug, PartialEq, Eq, thiserror::Error)]
+pub enum SshHostKeyProbeError {
+    #[error("SSH host key probe hostname is invalid")]
+    InvalidHostname,
+    #[error("SSH host key probe port must be greater than zero")]
+    InvalidPort,
+    #[error("SSH host key probe executable is unavailable")]
+    Unavailable,
+    #[error("SSH host key probe timed out")]
+    Timeout,
+    #[error("SSH host key probe failed: {diagnostic}")]
+    Failed { diagnostic: String },
+}
+
+/// Observe the target's public Ed25519 host keys without persisting trust or using credentials.
+pub async fn probe_ssh_host_keys(
+    request: &SshHostKeyProbeRequest,
+) -> Result<SshHostKeyProbeResponse, SshHostKeyProbeError> {
+    probe_ssh_host_keys_with_program(request, Path::new("ssh-keyscan"), SSH_KEYSCAN_TIMEOUT).await
+}
+
+pub(crate) async fn probe_ssh_host_keys_with_program(
+    request: &SshHostKeyProbeRequest,
+    program: &Path,
+    timeout: Duration,
+) -> Result<SshHostKeyProbeResponse, SshHostKeyProbeError> {
+    validate_request(request)?;
+
+    let mut command = Command::new(program);
+    command
+        .args(["-T", SSH_KEYSCAN_CONNECT_TIMEOUT_SECONDS])
+        .arg("-p")
+        .arg(request.port.to_string())
+        .args(["-t", "ed25519"])
+        .arg(&request.hostname)
+        .stdin(Stdio::null())
+        .stdout(Stdio::piped())
+        // ssh-keyscan diagnostics are intentionally not returned or retained: they may contain
+        // environment-specific details and are not needed for the public error contract.
+        .stderr(Stdio::null())
+        .kill_on_drop(true);
+
+    let output = tokio::time::timeout(timeout, command.output())
+        .await
+        .map_err(|_| SshHostKeyProbeError::Timeout)?
+        .map_err(|_| SshHostKeyProbeError::Unavailable)?;
+
+    if !output.status.success() {
+        return Err(SshHostKeyProbeError::Failed {
+            diagnostic: bounded_diagnostic(format!(
+                "ssh-keyscan exited unsuccessfully ({})",
+                output.status
+            )),
+        });
+    }
+    if output.stdout.len() > MAX_SSH_KEYSCAN_OUTPUT_BYTES {
+        return Err(SshHostKeyProbeError::Failed {
+            diagnostic: "ssh-keyscan output exceeded the probe limit".to_string(),
+        });
+    }
+
+    let candidates = parse_ssh_keyscan_output(&output.stdout);
+    if candidates.is_empty() {
+        return Err(SshHostKeyProbeError::Failed {
+            diagnostic: "ssh-keyscan returned no valid ssh-ed25519 host keys".to_string(),
+        });
+    }
+    Ok(SshHostKeyProbeResponse { candidates })
+}
+
+fn validate_request(request: &SshHostKeyProbeRequest) -> Result<(), SshHostKeyProbeError> {
+    if request.port == 0 {
+        return Err(SshHostKeyProbeError::InvalidPort);
+    }
+    validate_hostname(&request.hostname)
+}
+
+fn validate_hostname(hostname: &str) -> Result<(), SshHostKeyProbeError> {
+    if hostname.is_empty()
+        || hostname.len() > 253
+        || !hostname.is_ascii()
+        || hostname.bytes().any(|byte| byte.is_ascii_whitespace())
+        || hostname.starts_with('-')
+    {
+        return Err(SshHostKeyProbeError::InvalidHostname);
+    }
+    if hostname.parse::<IpAddr>().is_ok() {
+        return Ok(());
+    }
+
+    let hostname = hostname.strip_suffix('.').unwrap_or(hostname);
+    if hostname.is_empty()
+        || hostname.split('.').any(|label| {
+            label.is_empty()
+                || label.len() > 63
+                || label.starts_with('-')
+                || label.ends_with('-')
+                || !label
+                    .bytes()
+                    .all(|byte| byte.is_ascii_alphanumeric() || byte == b'-')
+        })
+    {
+        return Err(SshHostKeyProbeError::InvalidHostname);
+    }
+    Ok(())
+}
+
+fn parse_ssh_keyscan_output(output: &[u8]) -> Vec<SshHostKeyCandidate> {
+    let mut seen = BTreeSet::new();
+    let mut candidates = Vec::new();
+    for line in output.split(|byte| *byte == b'\n') {
+        let Ok(line) = std::str::from_utf8(line) else {
+            continue;
+        };
+        let mut fields = line.split_ascii_whitespace();
+        let (Some(_host), Some(algorithm), Some(encoded_key)) =
+            (fields.next(), fields.next(), fields.next())
+        else {
+            continue;
+        };
+        if line.trim_start().starts_with('#') || algorithm != "ssh-ed25519" {
+            continue;
+        }
+        let Ok(key_blob) = STANDARD.decode(encoded_key) else {
+            continue;
+        };
+        if !is_ed25519_public_key_blob(&key_blob) {
+            continue;
+        }
+
+        let canonical_key = STANDARD.encode(&key_blob);
+        if !seen.insert(canonical_key.clone()) {
+            continue;
+        }
+        let public_key = format!("{algorithm} {canonical_key}");
+        candidates.push(SshHostKeyCandidate {
+            algorithm: algorithm.to_string(),
+            fingerprint: format!(
+                "SHA256:{}",
+                STANDARD_NO_PAD.encode(Sha256::digest(&key_blob))
+            ),
+            public_key,
+        });
+        if candidates.len() == MAX_PROBE_CANDIDATES {
+            break;
+        }
+    }
+    candidates
+}
+
+fn is_ed25519_public_key_blob(blob: &[u8]) -> bool {
+    let Some((algorithm, rest)) = take_ssh_string(blob) else {
+        return false;
+    };
+    let Some((public_key, rest)) = take_ssh_string(rest) else {
+        return false;
+    };
+    algorithm == b"ssh-ed25519" && public_key.len() == 32 && rest.is_empty()
+}
+
+fn take_ssh_string(input: &[u8]) -> Option<(&[u8], &[u8])> {
+    let length = u32::from_be_bytes(input.get(..4)?.try_into().ok()?) as usize;
+    let value = input.get(4..4usize.checked_add(length)?)?;
+    let rest = input.get(4usize.checked_add(length)?..)?;
+    Some((value, rest))
+}
+
+fn bounded_diagnostic(mut diagnostic: String) -> String {
+    if diagnostic.len() <= MAX_DIAGNOSTIC_BYTES {
+        return diagnostic;
+    }
+    let mut end = MAX_DIAGNOSTIC_BYTES;
+    while !diagnostic.is_char_boundary(end) {
+        end -= 1;
+    }
+    diagnostic.truncate(end);
+    diagnostic
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn encoded_ed25519_key(seed: u8) -> String {
+        let mut blob = Vec::new();
+        blob.extend_from_slice(&("ssh-ed25519".len() as u32).to_be_bytes());
+        blob.extend_from_slice(b"ssh-ed25519");
+        blob.extend_from_slice(&32_u32.to_be_bytes());
+        blob.extend_from_slice(&[seed; 32]);
+        STANDARD.encode(blob)
+    }
+
+    #[test]
+    fn hostname_validation_rejects_option_injection_and_ambiguous_text() {
+        for hostname in [
+            "",
+            "-example.test",
+            "--help",
+            "example.test other.test",
+            "example.test\nother.test",
+            "example_test",
+            ".example.test",
+            "example..test",
+            "example.test:22",
+            "[::1]",
+            "éxample.test",
+        ] {
+            assert_eq!(
+                validate_hostname(hostname),
+                Err(SshHostKeyProbeError::InvalidHostname),
+                "{hostname:?} must be rejected"
+            );
+        }
+        for hostname in [
+            "localhost",
+            "example.test",
+            "example.test.",
+            "127.0.0.1",
+            "::1",
+        ] {
+            validate_hostname(hostname).unwrap();
+        }
+    }
+
+    #[test]
+    fn request_validation_rejects_zero_port() {
+        assert_eq!(
+            validate_request(&SshHostKeyProbeRequest {
+                hostname: "example.test".to_string(),
+                port: 0,
+            }),
+            Err(SshHostKeyProbeError::InvalidPort)
+        );
+    }
+
+    #[test]
+    fn parser_accepts_only_valid_ed25519_keys_and_deduplicates() {
+        let key = encoded_ed25519_key(7);
+        let other_key = encoded_ed25519_key(8);
+        let output = format!(
+            "# comment\nexample.test ssh-rsa AAAA\nexample.test ssh-ed25519 invalid!\nexample.test ssh-ed25519 {key}\n[example.test]:2222 ssh-ed25519 {key}\nexample.test ssh-ed25519 {other_key}\n"
+        );
+
+        let candidates = parse_ssh_keyscan_output(output.as_bytes());
+
+        assert_eq!(candidates.len(), 2);
+        assert_eq!(candidates[0].algorithm, "ssh-ed25519");
+        assert_eq!(candidates[0].public_key, format!("ssh-ed25519 {key}"));
+        let decoded = STANDARD.decode(key).unwrap();
+        assert_eq!(
+            candidates[0].fingerprint,
+            format!("SHA256:{}", STANDARD_NO_PAD.encode(Sha256::digest(decoded)))
+        );
+    }
+
+    #[test]
+    fn parser_rejects_base64_that_is_not_an_ed25519_wire_key() {
+        let output = format!("example.test ssh-ed25519 {}\n", STANDARD.encode([1_u8; 32]));
+        assert!(parse_ssh_keyscan_output(output.as_bytes()).is_empty());
+    }
+
+    #[cfg(unix)]
+    #[tokio::test]
+    async fn unsuccessful_command_does_not_return_stderr() {
+        use std::os::unix::fs::PermissionsExt as _;
+
+        let temp = tempfile::tempdir().unwrap();
+        let program = temp.path().join("ssh-keyscan");
+        std::fs::write(
+            &program,
+            "#!/bin/sh\nprintf 'secret from stderr' >&2\nexit 7\n",
+        )
+        .unwrap();
+        std::fs::set_permissions(&program, std::fs::Permissions::from_mode(0o700)).unwrap();
+        let error = probe_ssh_host_keys_with_program(
+            &SshHostKeyProbeRequest {
+                hostname: "example.test".to_string(),
+                port: 22,
+            },
+            &program,
+            Duration::from_secs(1),
+        )
+        .await
+        .unwrap_err();
+
+        let diagnostic = error.to_string();
+        assert!(matches!(error, SshHostKeyProbeError::Failed { .. }));
+        assert!(!diagnostic.contains("secret"));
+        assert!(diagnostic.len() <= MAX_DIAGNOSTIC_BYTES + "SSH host key probe failed: ".len());
+    }
+
+    #[cfg(unix)]
+    #[tokio::test]
+    async fn command_execution_times_out_without_returning_process_diagnostics() {
+        use std::os::unix::fs::PermissionsExt as _;
+
+        let temp = tempfile::tempdir().unwrap();
+        let program = temp.path().join("ssh-keyscan");
+        std::fs::write(
+            &program,
+            "#!/bin/sh\nprintf 'secret from stderr' >&2\nsleep 2\n",
+        )
+        .unwrap();
+        std::fs::set_permissions(&program, std::fs::Permissions::from_mode(0o700)).unwrap();
+        let request = SshHostKeyProbeRequest {
+            hostname: "example.test".to_string(),
+            port: 22,
+        };
+
+        let error = probe_ssh_host_keys_with_program(&request, &program, Duration::from_millis(20))
+            .await
+            .unwrap_err();
+
+        assert_eq!(error, SshHostKeyProbeError::Timeout);
+        assert!(!error.to_string().contains("secret"));
+    }
+}

crates/workspace-api/src/lib.rs

@@ -1152,6 +1152,58 @@ pub struct RepositoryDetailResponse {
     pub source: String,
 }
 
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
+#[cfg_attr(feature = "typescript", derive(ts_rs::TS))]
+#[serde(deny_unknown_fields)]
+pub struct RepositorySshConnectionProbeRequest {
+    pub runtime_id: String,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
+#[cfg_attr(feature = "typescript", derive(ts_rs::TS))]
+#[serde(deny_unknown_fields)]
+pub struct RepositorySshHostKeyCandidate {
+    pub algorithm: String,
+    pub host_key: String,
+    pub fingerprint: String,
+}
+
+#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
+#[cfg_attr(feature = "typescript", derive(ts_rs::TS))]
+#[serde(rename_all = "snake_case")]
+pub enum RepositorySshConnectionTrustState {
+    Untrusted,
+    Verified,
+    Changed,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
+#[cfg_attr(feature = "typescript", derive(ts_rs::TS))]
+#[serde(deny_unknown_fields)]
+pub struct RepositorySshConnectionProbeResponse {
+    pub workspace_id: String,
+    pub repository_key: String,
+    pub runtime_id: String,
+    pub hostname: String,
+    pub port: u16,
+    pub trust_state: RepositorySshConnectionTrustState,
+    pub host_trust_id: String,
+    #[cfg_attr(feature = "typescript", ts(type = "number | null"))]
+    pub expected_host_trust_revision: Option<u64>,
+    pub candidates: Vec<RepositorySshHostKeyCandidate>,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
+#[cfg_attr(feature = "typescript", derive(ts_rs::TS))]
+#[serde(deny_unknown_fields)]
+pub struct ConfirmRepositorySshHostTrustRequest {
+    pub operation_id: String,
+    pub runtime_id: String,
+    pub host_key: String,
+    #[cfg_attr(feature = "typescript", ts(type = "number | null"))]
+    pub expected_host_trust_revision: Option<u64>,
+}
+
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
 #[cfg_attr(feature = "typescript", derive(ts_rs::TS))]
 #[serde(deny_unknown_fields)]
@@ -2455,6 +2507,27 @@ pub struct CreateRepositorySshCredentialRequest {
     pub passphrase: Option<String>,
 }
 
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
+#[cfg_attr(feature = "typescript", derive(ts_rs::TS))]
+#[serde(deny_unknown_fields)]
+pub struct GenerateRepositorySshCredentialRequest {
+    pub operation_id: String,
+    pub credential_id: String,
+    pub name: String,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
+#[cfg_attr(feature = "typescript", derive(ts_rs::TS))]
+#[serde(deny_unknown_fields)]
+pub struct RepositorySshPublicKey {
+    pub credential_id: String,
+    #[cfg_attr(feature = "typescript", ts(type = "number"))]
+    pub current_revision: u64,
+    pub public_key_algorithm: String,
+    pub public_key_fingerprint: String,
+    pub public_key: String,
+}
+
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
 #[cfg_attr(feature = "typescript", derive(ts_rs::TS))]
 #[serde(deny_unknown_fields)]
@@ -2997,6 +3070,11 @@ pub fn catalog_typescript() -> String {
         GitCommitSummary::decl(&config),
         RepositoryListResponse::decl(&config),
         RepositoryDetailResponse::decl(&config),
+        RepositorySshConnectionProbeRequest::decl(&config),
+        RepositorySshHostKeyCandidate::decl(&config),
+        RepositorySshConnectionTrustState::decl(&config),
+        RepositorySshConnectionProbeResponse::decl(&config),
+        ConfirmRepositorySshHostTrustRequest::decl(&config),
         RepositoryLogResponse::decl(&config),
         RuntimeSourceKind::decl(&config),
         RuntimeSourceStatus::decl(&config),
@@ -3041,6 +3119,8 @@ pub fn repository_access_api_typescript() -> String {
     let declarations = [
         RepositorySshCredential::decl(&config),
         CreateRepositorySshCredentialRequest::decl(&config),
+        GenerateRepositorySshCredentialRequest::decl(&config),
+        RepositorySshPublicKey::decl(&config),
         RotateRepositorySshCredentialRequest::decl(&config),
         DeleteRepositorySshCredentialRequest::decl(&config),
         RepositorySshHostTrust::decl(&config),

crates/workspace-server/src/hosts.rs

@@ -67,6 +67,10 @@ use worker_runtime::profile_archive::ProfileSourceArchive;
 use worker_runtime::retention::{
     WorkerRetentionExecutionRequest, WorkerRetentionExecutionResult, WorkerRetentionInventory,
 };
+use worker_runtime::ssh_host_key_probe::{
+    SSH_HOST_KEY_PROBE_OPERATION, SSH_HOST_KEY_PROBE_PATH, SshHostKeyProbeRequest,
+    SshHostKeyProbeResponse,
+};
 use worker_runtime::workspace_issuer::{
     WorkspaceCapabilityClaims, WorkspaceRuntimeVerificationAcknowledgement,
     WorkspaceRuntimeVerificationChallenge, WorkspaceRuntimeVerificationReceipt,
@@ -82,6 +86,9 @@ const MAX_REMOTE_RUNTIME_RESPONSE_BYTES: usize = 16 * 1024 * 1024;
 // Runtime creation can spend up to 60s bootstrapping; durable Submit
 // acceptance is acknowledged before the potentially long run preparation.
 const REMOTE_WORKER_CREATE_TIMEOUT: Duration = Duration::from_secs(80);
+// Repository materialization can spend up to 300s in Git. Keep the HTTP
+// caller alive long enough for Runtime to return its bounded result.
+const REMOTE_WORKING_DIRECTORY_CREATE_TIMEOUT: Duration = Duration::from_secs(330);
 const MAX_HOST_SCAN: usize = 256;
 const MAX_IDENTIFIER_LEN: usize = 120;
 const ID_DIGEST_HEX_LEN: usize = 16;
@@ -826,6 +833,17 @@ pub trait WorkspaceWorkerRuntime: Send + Sync {
         ))
     }
 
+    fn probe_ssh_host_keys(
+        &self,
+        _request: SshHostKeyProbeRequest,
+    ) -> std::result::Result<SshHostKeyProbeResponse, Error> {
+        Err(Error::RuntimeOperationFailed {
+            runtime_id: self.runtime_id().to_string(),
+            code: "ssh_host_key_probe_unsupported".to_string(),
+            message: "Runtime does not support SSH host key probing".to_string(),
+        })
+    }
+
     fn activate_workspace_authorization(&self, _binding: crate::store::WorkspaceRuntimeBinding) {}
 
     fn send_workspace_verification_challenge(
@@ -1569,6 +1587,31 @@ impl RuntimeRegistry {
             })
     }
 
+    pub fn probe_ssh_host_keys(
+        &self,
+        runtime_id: &str,
+        request: SshHostKeyProbeRequest,
+    ) -> Result<SshHostKeyProbeResponse, RuntimeRegistryError> {
+        validate_backend_identifier("runtime_id", runtime_id)?;
+        let runtime = self.runtime(runtime_id)?;
+        runtime
+            .probe_ssh_host_keys(request)
+            .map_err(|error| match error {
+                Error::RuntimeOperationFailed { code, message, .. } => {
+                    RuntimeRegistryError::RuntimeOperationFailed {
+                        runtime_id: runtime_id.to_string(),
+                        code,
+                        message,
+                    }
+                }
+                other => RuntimeRegistryError::RuntimeOperationFailed {
+                    runtime_id: runtime_id.to_string(),
+                    code: "ssh_host_key_probe_failed".to_string(),
+                    message: other.to_string(),
+                },
+            })
+    }
+
     pub fn observe_repository_ref(
         &self,
         runtime_id: &str,
@@ -3404,10 +3447,11 @@ fn workspace_runtime_operation(method: &str, path_and_query: &str) -> &'static s
         return "workers:create";
     }
     if (path == "/v1/working-directories/repository-access"
-        || path == "/v1/repository-refs/observe")
+        || path == "/v1/repository-refs/observe"
+        || path == SSH_HOST_KEY_PROBE_PATH)
         && method == "POST"
     {
-        return "workdirs:operate";
+        return SSH_HOST_KEY_PROBE_OPERATION;
     }
     if path.starts_with("/v1/workdir-sessions")
         || (path.starts_with("/v1/working-directories/") && path.ends_with("/sessions"))
@@ -3631,6 +3675,19 @@ impl RemoteWorkerRuntime {
     }
 
     fn post_json<B, T>(&self, path: &str, body: &B) -> Result<T, RuntimeDiagnostic>
+    where
+        B: Serialize + ?Sized,
+        T: DeserializeOwned + Send + 'static,
+    {
+        self.post_json_with_timeout(path, body, None)
+    }
+
+    fn post_json_with_timeout<B, T>(
+        &self,
+        path: &str,
+        body: &B,
+        timeout: Option<Duration>,
+    ) -> Result<T, RuntimeDiagnostic>
     where
         B: Serialize + ?Sized,
         T: DeserializeOwned + Send + 'static,
@@ -3642,15 +3699,15 @@ impl RemoteWorkerRuntime {
                 error.to_string(),
             )
         })?;
-        self.send_json(
+        let mut request = self
-            path,
+            .http
-            "POST",
-            &body,
-            self.http
             .post(self.endpoint(path))
             .header(CONTENT_TYPE, "application/json")
-                .body(body.clone()),
+            .body(body.clone());
-        )
+        if let Some(timeout) = timeout {
+            request = request.timeout(timeout);
+        }
+        self.send_json(path, "POST", &body, request)
     }
 
     fn post_bytes<T>(&self, path: &str, body: &[u8]) -> Result<T, RuntimeDiagnostic>
@@ -4140,9 +4197,10 @@ impl WorkspaceWorkerRuntime for RemoteWorkerRuntime {
         &self,
         request: WorkingDirectoryRequest,
     ) -> RuntimeWorkingDirectoryResult {
-        match self.post_json::<_, RuntimeHttpWorkingDirectoryResponse>(
+        match self.post_json_with_timeout::<_, RuntimeHttpWorkingDirectoryResponse>(
             "/v1/working-directories",
             &request,
+            Some(REMOTE_WORKING_DIRECTORY_CREATE_TIMEOUT),
         ) {
             Ok(response) => RuntimeWorkingDirectoryResult {
                 state: WorkerOperationState::Accepted,
@@ -4169,6 +4227,18 @@ impl WorkspaceWorkerRuntime for RemoteWorkerRuntime {
         .map_err(|diagnostic| Error::RegistryInconsistency(diagnostic.message))
     }
 
+    fn probe_ssh_host_keys(
+        &self,
+        request: SshHostKeyProbeRequest,
+    ) -> std::result::Result<SshHostKeyProbeResponse, Error> {
+        self.post_json::<_, SshHostKeyProbeResponse>(SSH_HOST_KEY_PROBE_PATH, &request)
+            .map_err(|diagnostic| Error::RuntimeOperationFailed {
+                runtime_id: self.runtime_id.clone(),
+                code: diagnostic.code,
+                message: diagnostic.message,
+            })
+    }
+
     fn observe_repository_ref(
         &self,
         request: RepositoryRefObservationRequest,
@@ -5369,6 +5439,15 @@ mod tests {
         assert!(REMOTE_WORKER_CREATE_TIMEOUT > Duration::from_secs(60 + 10 + 5));
     }
 
+    #[test]
+    fn remote_working_directory_create_timeout_covers_git_budget() {
+        assert!(REMOTE_WORKING_DIRECTORY_CREATE_TIMEOUT > Duration::from_secs(300));
+        assert!(
+            REMOTE_WORKING_DIRECTORY_CREATE_TIMEOUT
+                > worker_runtime::resource::DEFAULT_BACKEND_RESOURCE_FETCH_TIMEOUT
+        );
+    }
+
     fn test_create_binding() -> WorkerCreateBinding {
         WorkerCreateBinding {
             worker_id: EmbeddedWorkerId::now_v7(),
@@ -6593,6 +6672,10 @@ mod tests {
             workspace_runtime_operation("GET", &format!("/v1/workers/{worker_id}/protocol/ws")),
             "workers:protocol"
         );
+        assert_eq!(
+            workspace_runtime_operation("POST", SSH_HOST_KEY_PROBE_PATH),
+            SSH_HOST_KEY_PROBE_OPERATION
+        );
     }
 
     #[test]

crates/workspace-server/src/repository_access.rs

@@ -7,16 +7,19 @@ use std::sync::Arc;
 use chrono::{SecondsFormat, Utc};
 use config_source::ConfigSchemaContribution;
 use ring::aead::{AES_256_GCM, Aad, LessSafeKey, Nonce, UnboundKey};
+use ring::hmac;
 use ring::rand::{SecureRandom, SystemRandom};
 use rusqlite::{OptionalExtension, TransactionBehavior, params};
 use serde::Deserialize;
 use sha2::{Digest, Sha256};
+use ssh_key::private::Ed25519Keypair;
 use ssh_key::{Algorithm, HashAlg, LineEnding, PrivateKey, PublicKey};
 use workspace_api::{
     CreateRepositorySshCredentialRequest, DeleteRepositorySshCredentialRequest,
-    DeleteRepositorySshHostTrustRequest, PutRepositorySshHostTrustRequest, RepositoryAccessMode,
+    DeleteRepositorySshHostTrustRequest, GenerateRepositorySshCredentialRequest,
-    RepositoryAccessProjection, RepositorySshAccessBinding, RepositorySshCredential,
+    PutRepositorySshHostTrustRequest, RepositoryAccessMode, RepositoryAccessProjection,
-    RepositorySshHostTrust, RotateRepositorySshCredentialRequest,
+    RepositorySshAccessBinding, RepositorySshCredential, RepositorySshHostTrust,
+    RepositorySshPublicKey, RotateRepositorySshCredentialRequest,
 };
 
 use crate::config_source::{
@@ -42,6 +45,9 @@ const MAX_NAME_BYTES: usize = 200;
 const MAX_IDENTIFIER_BYTES: usize = 128;
 const MASTER_KEY_BYTES: usize = 32;
 const NONCE_BYTES: usize = 12;
+pub const WORKSPACE_DEFAULT_REPOSITORY_SSH_CREDENTIAL_ID: &str = "workspace-default";
+const WORKSPACE_DEFAULT_REPOSITORY_SSH_OPERATION_ID: &str = "workspace-default-repository-ssh-v1";
+const WORKSPACE_DEFAULT_REPOSITORY_SSH_NAME: &str = "Workspace default SSH key";
 
 #[derive(Debug, Default)]
 pub struct RepositoryAccessConfigSchemaProvider;
@@ -130,6 +136,43 @@ pub fn project_repository_access_state(
     )
 }
 
+pub(crate) fn repository_ssh_endpoint(
+    repository_key: &str,
+    repository_uri: &str,
+) -> Result<Option<(String, u16)>> {
+    if !repository_uri.contains("://") {
+        if let Some((identity, path)) = repository_uri.split_once(':')
+            && !path.is_empty()
+            && let Some((_, hostname)) = identity.rsplit_once('@')
+            && !hostname.is_empty()
+        {
+            return Ok(Some((hostname.to_ascii_lowercase(), 22)));
+        }
+    }
+    let parsed = url::Url::parse(repository_uri).map_err(|error| {
+        Error::InvalidInput(format!(
+            "Repository `{repository_key}` has invalid SSH URI: {error}"
+        ))
+    })?;
+    if parsed.scheme() != "ssh" {
+        return Ok(None);
+    }
+    if parsed.username().is_empty() || parsed.password().is_some() {
+        return Err(Error::InvalidInput(format!(
+            "Repository `{repository_key}` must use ssh://user@host[:port]/path without embedded credentials"
+        )));
+    }
+    let hostname = parsed.host_str().ok_or_else(|| {
+        Error::InvalidInput(format!(
+            "Repository `{repository_key}` SSH URI has no hostname"
+        ))
+    })?;
+    Ok(Some((
+        hostname.to_ascii_lowercase(),
+        parsed.port().unwrap_or(22),
+    )))
+}
+
 fn project_repository_access_evaluation(
     store: &dyn ControlPlaneStore,
     secrets: &RepositorySecretService,
@@ -145,6 +188,9 @@ fn project_repository_access_evaluation(
         .map_err(|error| {
             Error::InvalidInput(format!("invalid Repository access config: {error}"))
         })?;
+    if !config.repository_access.is_empty() {
+        secrets.ensure_workspace_default_credential(workspace_id)?;
+    }
     let mut bindings = Vec::with_capacity(config.repository_access.len());
     for (repository_key, access) in config.repository_access {
         workspace_api::validate_repository_key(&repository_key)
@@ -181,22 +227,14 @@ fn project_repository_access_evaluation(
                     access.ssh.host_trust
                 ))
             })?;
-        let uri = url::Url::parse(&repository.source.uri).map_err(|_| {
+        let (hostname, port) =
+            repository_ssh_endpoint(repository_key.as_str(), &repository.source.uri)?.ok_or_else(
+                || {
                     Error::InvalidInput(format!(
-                "Repository `{repository_key}` has an invalid SSH URI"
+                        "Repository `{repository_key}` must use an SSH source"
                     ))
-        })?;
+                },
-        if uri.scheme() != "ssh" || uri.username().is_empty() || uri.password().is_some() {
+            )?;
-            return Err(Error::InvalidInput(format!(
-                "Repository `{repository_key}` must use ssh://user@host[:port]/path without credentials"
-            )));
-        }
-        let hostname = uri.host_str().ok_or_else(|| {
-            Error::InvalidInput(format!(
-                "Repository `{repository_key}` SSH URI has no hostname"
-            ))
-        })?;
-        let port = uri.port().unwrap_or(22);
         if hostname != host_trust.hostname || port != host_trust.port {
             return Err(Error::InvalidInput(format!(
                 "Repository `{repository_key}` SSH host does not match host trust `{}`",
@@ -245,6 +283,152 @@ impl RepositorySecretService {
         })
     }
 
+    fn generated_ed25519_private_key(
+        &self,
+        workspace_id: &str,
+        operation_id: &str,
+        credential_id: &str,
+        intent: &str,
+    ) -> Result<String> {
+        let master_key = self.master_key.as_ref().ok_or_else(|| {
+            Error::Store("Repository secret encryption authority is unavailable".to_string())
+        })?;
+        let key = hmac::Key::new(hmac::HMAC_SHA256, master_key.as_slice());
+        let context = format!(
+            "yoi/repository-ssh-key/v1\0{workspace_id}\0{operation_id}\0{credential_id}\0{intent}"
+        );
+        let seed = hmac::sign(&key, context.as_bytes());
+        PrivateKey::from(Ed25519Keypair::from_seed(
+            seed.as_ref().try_into().map_err(|_| {
+                Error::Store("generated SSH Ed25519 seed had an invalid length".to_string())
+            })?,
+        ))
+        .to_openssh(LineEnding::LF)
+        .map(|key| key.to_string())
+        .map_err(|err| Error::Store(format!("failed to encode generated SSH key: {err}")))
+    }
+
+    pub fn generate_credential(
+        &self,
+        workspace_id: &str,
+        request: GenerateRepositorySshCredentialRequest,
+        actor_account_id: &str,
+    ) -> Result<RepositorySshCredential> {
+        let operation_id = validate_identifier("operation_id", &request.operation_id)?;
+        let credential_id = validate_identifier("credential_id", &request.credential_id)?;
+        let name = normalize_name(&request.name)?;
+        let private_key = self.generated_ed25519_private_key(
+            workspace_id,
+            &operation_id,
+            &credential_id,
+            &format!("create\0{name}"),
+        )?;
+        self.create_credential(
+            workspace_id,
+            CreateRepositorySshCredentialRequest {
+                operation_id,
+                credential_id,
+                name,
+                private_key,
+                passphrase: None,
+            },
+            actor_account_id,
+        )
+    }
+
+    pub fn ensure_workspace_default_credential(
+        &self,
+        workspace_id: &str,
+    ) -> Result<RepositorySshCredential> {
+        if let Some(credential) = self.store.with_conn(|conn| {
+            read_credential(
+                conn,
+                workspace_id,
+                WORKSPACE_DEFAULT_REPOSITORY_SSH_CREDENTIAL_ID,
+            )
+        })? {
+            return Ok(credential);
+        }
+        self.generate_credential(
+            workspace_id,
+            GenerateRepositorySshCredentialRequest {
+                operation_id: WORKSPACE_DEFAULT_REPOSITORY_SSH_OPERATION_ID.to_string(),
+                credential_id: WORKSPACE_DEFAULT_REPOSITORY_SSH_CREDENTIAL_ID.to_string(),
+                name: WORKSPACE_DEFAULT_REPOSITORY_SSH_NAME.to_string(),
+            },
+            "workspace-system",
+        )
+    }
+
+    pub fn credential_public_key(
+        &self,
+        workspace_id: &str,
+        credential_id: &str,
+    ) -> Result<Option<RepositorySshPublicKey>> {
+        let credential_id = validate_identifier("credential_id", credential_id)?;
+        let Some((credential, private_secret, passphrase_secret)) =
+            self.store.with_conn(|conn| {
+                let Some(credential) = read_credential(conn, workspace_id, &credential_id)? else {
+                    return Ok(None);
+                };
+                let private_secret = read_sealed_secret(
+                    conn,
+                    workspace_id,
+                    &credential_id,
+                    credential.current_revision,
+                    "private_key",
+                )?
+                .ok_or_else(|| Error::Store("credential private key is missing".to_string()))?;
+                let passphrase_secret = read_sealed_secret(
+                    conn,
+                    workspace_id,
+                    &credential_id,
+                    credential.current_revision,
+                    "passphrase",
+                )?;
+                Ok(Some((credential, private_secret, passphrase_secret)))
+            })?
+        else {
+            return Ok(None);
+        };
+        let private_key = zeroize::Zeroizing::new(self.unseal(
+            workspace_id,
+            &credential_id,
+            credential.current_revision,
+            "private_key",
+            private_secret,
+        )?);
+        let passphrase = passphrase_secret
+            .map(|secret| {
+                self.unseal(
+                    workspace_id,
+                    &credential_id,
+                    credential.current_revision,
+                    "passphrase",
+                    secret,
+                )
+                .map(zeroize::Zeroizing::new)
+            })
+            .transpose()?;
+        let private_key = std::str::from_utf8(private_key.as_slice())
+            .map_err(|_| Error::Store("credential private key is not UTF-8".to_string()))?;
+        let passphrase = passphrase
+            .as_deref()
+            .map(|value| std::str::from_utf8(value.as_slice()))
+            .transpose()
+            .map_err(|_| Error::Store("credential passphrase is not UTF-8".to_string()))?;
+        let parsed = parse_private_key(private_key, passphrase).map_err(|err| {
+            Error::Store(format!("stored credential private key is invalid: {err}"))
+        })?;
+        Ok(Some(RepositorySshPublicKey {
+            credential_id,
+            current_revision: credential.current_revision,
+            public_key_algorithm: parsed.algorithm,
+            public_key_fingerprint: parsed.fingerprint,
+            public_key: parsed.public_key,
+        }))
+    }
+
     pub fn create_credential(
         &self,
         workspace_id: &str,
@@ -384,6 +568,11 @@ impl RepositorySecretService {
         actor_account_id: &str,
     ) -> Result<RepositorySshCredential> {
         let credential_id = validate_identifier("credential_id", credential_id)?;
+        if credential_id == WORKSPACE_DEFAULT_REPOSITORY_SSH_CREDENTIAL_ID {
+            return Err(Error::WorkspaceConfigConflict(
+                "Workspace default SSH credential is immutable".to_string(),
+            ));
+        }
         let operation_id = validate_identifier("operation_id", &request.operation_id)?;
         let parsed = parse_private_key(&request.private_key, request.passphrase.as_deref())?;
         let next_revision = request
@@ -529,6 +718,11 @@ impl RepositorySecretService {
         projection: &RepositoryAccessProjection,
     ) -> Result<()> {
         let credential_id = validate_identifier("credential_id", credential_id)?;
+        if credential_id == WORKSPACE_DEFAULT_REPOSITORY_SSH_CREDENTIAL_ID {
+            return Err(Error::WorkspaceConfigConflict(
+                "Workspace default SSH credential is immutable".to_string(),
+            ));
+        }
         let operation_id = validate_identifier("operation_id", &request.operation_id)?;
         let references = credential_references(projection, &credential_id);
         if !references.is_empty() {
@@ -839,6 +1033,73 @@ impl RepositorySecretService {
         })
     }
 
+    pub fn host_trusts_for_endpoint(
+        &self,
+        workspace_id: &str,
+        hostname: &str,
+        port: u16,
+    ) -> Result<Vec<RepositorySshHostTrust>> {
+        self.store.with_conn(|conn| {
+            let mut statement = conn.prepare(
+                r#"SELECT workspace_id, host_trust_id, hostname, port, key_algorithm,
+                          host_key, fingerprint, current_revision, created_at, updated_at
+                   FROM repository_ssh_host_trusts
+                   WHERE workspace_id = ?1 AND lower(hostname) = lower(?2) AND port = ?3
+                   ORDER BY host_trust_id"#,
+            )?;
+            statement
+                .query_map(
+                    params![workspace_id, hostname, i64::from(port)],
+                    read_host_trust_row,
+                )?
+                .collect::<std::result::Result<Vec<_>, _>>()
+                .map_err(Error::from)
+        })
+    }
+
+    pub fn automatic_host_trust_id(hostname: &str, port: u16) -> String {
+        let normalized = hostname
+            .chars()
+            .map(|character| {
+                if character.is_ascii_alphanumeric() || matches!(character, '.' | '-' | '_') {
+                    character.to_ascii_lowercase()
+                } else {
+                    '-'
+                }
+            })
+            .take(96)
+            .collect::<String>();
+        format!("tofu-{normalized}-{port}")
+    }
+
+    pub fn default_ssh_binding_for_repository(
+        &self,
+        workspace_id: &str,
+        repository_key: &str,
+        repository_uri: &str,
+    ) -> Result<Option<RepositorySshAccessBinding>> {
+        let Some((hostname, port)) = repository_ssh_endpoint(repository_key, repository_uri)?
+        else {
+            return Ok(None);
+        };
+        let matches = self.host_trusts_for_endpoint(workspace_id, &hostname, port)?;
+        let Some(host_trust) = matches.first() else {
+            return Ok(None);
+        };
+        if matches.len() > 1 {
+            return Err(Error::InvalidInput(format!(
+                "Repository `{repository_key}` matches multiple SSH host trusts for {hostname}:{port}; configure an explicit Repository access binding"
+            )));
+        }
+        self.ensure_workspace_default_credential(workspace_id)?;
+        Ok(Some(RepositorySshAccessBinding {
+            repository_key: repository_key.to_string(),
+            credential_id: WORKSPACE_DEFAULT_REPOSITORY_SSH_CREDENTIAL_ID.to_string(),
+            host_trust_id: host_trust.host_trust_id.clone(),
+            access: RepositoryAccessMode::ReadOnly,
+        }))
+    }
+
     pub fn lease_ssh_materialization_access(
         &self,
         workspace_id: &str,
@@ -1056,6 +1317,7 @@ impl RepositorySecretService {
 struct ParsedKey {
     algorithm: String,
     fingerprint: String,
+    public_key: String,
 }
 
 fn parse_private_key(private_key: &str, passphrase: Option<&str>) -> Result<ParsedKey> {
@@ -1092,6 +1354,9 @@ fn parse_private_key(private_key: &str, passphrase: Option<&str>) -> Result<Pars
     Ok(ParsedKey {
         algorithm: public_key.algorithm().to_string(),
         fingerprint: public_key.fingerprint(HashAlg::Sha256).to_string(),
+        public_key: public_key.to_openssh().map_err(|err| {
+            Error::Store(format!("failed to encode Repository SSH public key: {err}"))
+        })?,
     })
 }
 
@@ -1708,6 +1973,102 @@ mod tests {
         assert!(!error.contains(secret));
     }
 
+    #[test]
+    fn workspace_default_credential_is_generated_once_and_immutable() {
+        let (_dir, _store, service) = test_service();
+
+        let created = service
+            .ensure_workspace_default_credential("workspace-a")
+            .unwrap();
+        let replayed = service
+            .ensure_workspace_default_credential("workspace-a")
+            .unwrap();
+        let public_key = service
+            .credential_public_key(
+                "workspace-a",
+                WORKSPACE_DEFAULT_REPOSITORY_SSH_CREDENTIAL_ID,
+            )
+            .unwrap()
+            .unwrap();
+
+        assert_eq!(created, replayed);
+        assert_eq!(created.current_revision, 1);
+        assert_eq!(
+            public_key.public_key_fingerprint,
+            created.public_key_fingerprint
+        );
+        assert!(
+            service
+                .rotate_credential(
+                    "workspace-a",
+                    WORKSPACE_DEFAULT_REPOSITORY_SSH_CREDENTIAL_ID,
+                    RotateRepositorySshCredentialRequest {
+                        operation_id: "rotate-default".to_string(),
+                        expected_revision: 1,
+                        private_key: test_private_key(12).0,
+                        passphrase: None,
+                    },
+                    "owner-a",
+                )
+                .is_err()
+        );
+        assert!(
+            service
+                .delete_credential(
+                    "workspace-a",
+                    WORKSPACE_DEFAULT_REPOSITORY_SSH_CREDENTIAL_ID,
+                    DeleteRepositorySshCredentialRequest {
+                        operation_id: "delete-default".to_string(),
+                        expected_revision: 1,
+                    },
+                    "owner-a",
+                    &RepositoryAccessProjection {
+                        workspace_id: "workspace-a".to_string(),
+                        config_revision: 1,
+                        projection_digest: "sha256:empty".to_string(),
+                        bindings: Vec::new(),
+                    },
+                )
+                .is_err()
+        );
+    }
+
+    #[test]
+    fn generated_credential_is_replayable_and_exposes_only_its_public_key() {
+        let (_dir, _store, service) = test_service();
+        let request = GenerateRepositorySshCredentialRequest {
+            operation_id: "generate-one".to_string(),
+            credential_id: "workspace-key".to_string(),
+            name: "Workspace key".to_string(),
+        };
+
+        let created = service
+            .generate_credential("workspace-a", request.clone(), "owner-a")
+            .unwrap();
+        let replayed = service
+            .generate_credential("workspace-a", request, "owner-a")
+            .unwrap();
+        let public_key = service
+            .credential_public_key("workspace-a", "workspace-key")
+            .unwrap()
+            .unwrap();
+
+        assert_eq!(replayed, created);
+        assert_eq!(public_key.current_revision, created.current_revision);
+        assert_eq!(
+            public_key.public_key_fingerprint,
+            created.public_key_fingerprint
+        );
+        assert!(public_key.public_key.starts_with("ssh-ed25519 "));
+        assert!(!public_key.public_key.contains("PRIVATE KEY"));
+        assert!(
+            service
+                .credential_public_key("workspace-b", "workspace-key")
+                .unwrap()
+                .is_none()
+        );
+    }
+
     #[test]
     fn credential_create_rotate_replay_and_cross_workspace_scope_keep_secrets_write_only() {
         let (_dir, store, service) = test_service();
@@ -1964,6 +2325,86 @@ mod tests {
         );
     }
 
+    #[test]
+    fn default_binding_resolves_unique_host_trust_for_url_and_scp_ssh_sources() {
+        let (_dir, _store, service) = test_service();
+        assert!(
+            service
+                .default_ssh_binding_for_repository(
+                    "workspace-a",
+                    "main",
+                    "git@example.test:org/main.git",
+                )
+                .unwrap()
+                .is_none()
+        );
+        let (_, host_key) = test_private_key(10);
+        service
+            .put_host_trust(
+                "workspace-a",
+                PutRepositorySshHostTrustRequest {
+                    operation_id: "host-default".to_string(),
+                    host_trust_id: "example".to_string(),
+                    hostname: "example.test".to_string(),
+                    port: 22,
+                    host_key,
+                    expected_revision: None,
+                },
+                "owner-a",
+            )
+            .unwrap();
+
+        for uri in [
+            "ssh://git@example.test/org/main.git",
+            "git@example.test:org/main.git",
+        ] {
+            let binding = service
+                .default_ssh_binding_for_repository("workspace-a", "main", uri)
+                .unwrap()
+                .unwrap();
+            assert_eq!(
+                binding.credential_id,
+                WORKSPACE_DEFAULT_REPOSITORY_SSH_CREDENTIAL_ID
+            );
+            assert_eq!(binding.host_trust_id, "example");
+            assert_eq!(binding.access, RepositoryAccessMode::ReadOnly);
+        }
+        assert!(
+            service
+                .credential_public_key(
+                    "workspace-a",
+                    WORKSPACE_DEFAULT_REPOSITORY_SSH_CREDENTIAL_ID,
+                )
+                .unwrap()
+                .is_some()
+        );
+
+        let (_, second_host_key) = test_private_key(11);
+        service
+            .put_host_trust(
+                "workspace-a",
+                PutRepositorySshHostTrustRequest {
+                    operation_id: "host-default-second".to_string(),
+                    host_trust_id: "example-second".to_string(),
+                    hostname: "example.test".to_string(),
+                    port: 22,
+                    host_key: second_host_key,
+                    expected_revision: None,
+                },
+                "owner-a",
+            )
+            .unwrap();
+        assert!(
+            service
+                .default_ssh_binding_for_repository(
+                    "workspace-a",
+                    "main",
+                    "git@example.test:org/main.git",
+                )
+                .is_err()
+        );
+    }
+
     #[test]
     fn referenced_resources_cannot_be_deleted() {
         let (_dir, _store, service) = test_service();

crates/workspace-server/src/resource_broker.rs

@@ -397,7 +397,13 @@ mod tests {
                 "1",
                 i64::MAX,
                 RepositorySshAccessSecret {
+                    credential_candidates: vec![
+                        worker_runtime::resource::RepositorySshAccessSecretCandidate {
+                            credential_id: "credential-test".to_string(),
+                            credential_revision: 1,
                             private_key: "private-key-bytes".to_string(),
+                        },
+                    ],
                     known_hosts_entry: "known-hosts-entry".to_string(),
                 },
             )
@@ -419,7 +425,10 @@ mod tests {
         assert!(!debug.contains("private-key-bytes"));
         assert!(debug.contains("REDACTED"));
         let secret: RepositorySshAccessSecret = serde_json::from_slice(&response.bytes).unwrap();
-        assert_eq!(secret.private_key, "private-key-bytes");
+        assert_eq!(
+            secret.credential_candidates[0].private_key,
+            "private-key-bytes"
+        );
         assert!(matches!(
             broker.fetch_resource(request(handle, "runtime-test", None)),
             Err(BackendResourceError::MissingResource)

crates/workspace-server/src/server.rs

@@ -70,28 +70,32 @@ use worker_runtime::workspace_issuer::{
 use workspace_api::{
     ActorAuthMethod, AuthBootstrapUserRequest, AuthPublicConfig, AuthUserResponse,
     AuthenticatedUser, BrowserCreateWorkerResponse, BrowserWorkspaceOrchestratorResponse,
-    CreateRemoteRuntimeRequest, CreateRepositorySshCredentialRequest,
+    ConfirmRepositorySshHostTrustRequest, CreateRemoteRuntimeRequest,
-    CreateWorkspaceRepositoryRequest, CreateWorkspaceRepositoryResponse,
+    CreateRepositorySshCredentialRequest, CreateWorkspaceRepositoryRequest,
-    CreateWorkspaceWorkerRequest, CreateWorkspaceWorkerTicketAssignmentRequest,
+    CreateWorkspaceRepositoryResponse, CreateWorkspaceWorkerRequest,
-    DeleteRepositorySshCredentialRequest, DeleteRepositorySshHostTrustRequest,
+    CreateWorkspaceWorkerTicketAssignmentRequest, DeleteRepositorySshCredentialRequest,
-    DeviceAccessTokenType, DeviceLoginApprovalStatus, DeviceLoginApproveRequest,
+    DeleteRepositorySshHostTrustRequest, DeviceAccessTokenType, DeviceLoginApprovalStatus,
-    DeviceLoginApproveResponse, DeviceLoginPollRequest, DeviceLoginPollResponse,
+    DeviceLoginApproveRequest, DeviceLoginApproveResponse, DeviceLoginPollRequest,
-    DeviceLoginPollStatus, DeviceLoginStartRequest, DeviceLoginStartResponse, LogoutResponse,
+    DeviceLoginPollResponse, DeviceLoginPollStatus, DeviceLoginStartRequest,
-    LogoutStatus, MemoryDocumentResponse, MemoryStagingListResponse, ObjectiveCreateRequest,
+    DeviceLoginStartResponse, GenerateRepositorySshCredentialRequest, LogoutResponse, LogoutStatus,
+    MemoryDocumentResponse, MemoryStagingListResponse, ObjectiveCreateRequest,
     ObjectiveEditRequest, ObjectiveLinkTicketRequest, ObjectiveStateRequest,
     PasskeyLoginCompleteRequest, PasskeyLoginOptionsRequest, PasskeyLoginOptionsResponse,
     PasskeyRegistrationCompleteRequest, PasskeyRegistrationOptionsRequest,
     PasskeyRegistrationOptionsResponse, ProfileSettingsResponse, PutRepositorySshHostTrustRequest,
     RepositoryAccessProjection, RepositoryDetailResponse, RepositoryListResponse,
-    RepositoryLogResponse, RepositorySshCredential, RepositorySshHostTrust, RequestActor,
+    RepositoryLogResponse, RepositorySshConnectionProbeRequest,
-    RevokeRuntimeTrustKeyRequest, RotateRepositorySshCredentialRequest,
+    RepositorySshConnectionProbeResponse, RepositorySshConnectionTrustState,
-    RuntimeConnectionDisplayState, RuntimeConnectionTestFailureKind, RuntimeConnectionTestResponse,
+    RepositorySshCredential, RepositorySshHostKeyCandidate, RepositorySshHostTrust,
-    RuntimeConnectionTestStatus, RuntimeManagementSummary, RuntimeTrustAuditAction,
+    RepositorySshPublicKey, RequestActor, RevokeRuntimeTrustKeyRequest,
-    RuntimeTrustAuditEntry, RuntimeTrustConflictKind, RuntimeTrustConflictResponse,
+    RotateRepositorySshCredentialRequest, RuntimeConnectionDisplayState,
-    RuntimeTrustKeyRevealResponse, RuntimeTrustKeyState, RuntimeTrustKeyStatus,
+    RuntimeConnectionTestFailureKind, RuntimeConnectionTestResponse, RuntimeConnectionTestStatus,
-    TICKET_ORCHESTRATION_PLANS_QUERY_PATH, TICKET_RELATIONS_QUERY_PATH,
+    RuntimeManagementSummary, RuntimeTrustAuditAction, RuntimeTrustAuditEntry,
-    UpdateWorkspaceMetadataRequest, WhoamiResponse, WorkerLaunchOptionsResponse,
+    RuntimeTrustConflictKind, RuntimeTrustConflictResponse, RuntimeTrustKeyRevealResponse,
-    WorkerLaunchProfileCandidate, WorkerLaunchRuntimeOption, WorkerLaunchWorkerSummary,
+    RuntimeTrustKeyState, RuntimeTrustKeyStatus, TICKET_ORCHESTRATION_PLANS_QUERY_PATH,
+    TICKET_RELATIONS_QUERY_PATH, UpdateWorkspaceMetadataRequest, WhoamiResponse,
+    WorkerLaunchOptionsResponse, WorkerLaunchProfileCandidate, WorkerLaunchRuntimeOption,
+    WorkerLaunchWorkerSummary,
     WorkingDirectoryCreateRequest as BrowserWorkingDirectoryCreateRequest,
     WorkingDirectoryCreateResponse as BrowserWorkingDirectoryCreateResponse,
     WorkingDirectoryDetailResponse as BrowserWorkingDirectoryDetailResponse,
@@ -188,8 +192,8 @@ use crate::{Error, Result};
 use worker_runtime::catalog::{
     ConfigBundleRef, ProfileSelector, RepositoryMaterializationContext, RepositoryRefObservation,
     RepositoryRefObservationRequest, RepositorySelector as RuntimeRepositorySelector,
-    RepositorySshMaterializationAccess, SensitiveString, WorkingDirectoryClaim,
+    RepositorySshCredentialCandidate, RepositorySshMaterializationAccess, SensitiveString,
-    WorkingDirectoryRepository, WorkingDirectoryRequest, WorkspaceApiRef,
+    WorkingDirectoryClaim, WorkingDirectoryRepository, WorkingDirectoryRequest, WorkspaceApiRef,
 };
 use worker_runtime::config_bundle::ConfigBundle;
 use worker_runtime::http_server::MAX_WORKER_FILE_UPLOAD_BYTES;
@@ -1860,6 +1864,19 @@ async fn enforce_server_cookie_mutation_origin(
     next.run(request).await
 }
 
+fn workspace_request_requires_mutation_lock(
+    method: &Method,
+    path: &str,
+    workspace_id: &str,
+) -> bool {
+    if matches!(*method, Method::GET | Method::HEAD | Method::OPTIONS) {
+        return false;
+    }
+    // Fetching a one-time Runtime resource consumes only an in-memory broker handle. It is a
+    // callback required to finish an already-gated mutation, not a Workspace state mutation.
+    path != format!("/api/runtime/v1/workspaces/{workspace_id}/resources/fetch")
+}
+
 async fn dispatch_workspace_request(
     State(api): State<WorkspaceServerApi>,
     mut request: Request,
@@ -1867,10 +1884,8 @@ async fn dispatch_workspace_request(
     let path = request.uri().path().to_owned();
     let workspace_id = scoped_workspace_id(&path);
     let _mutation_guard = if let Some(workspace_id) = workspace_id
-        && !matches!(
+        && workspace_request_requires_mutation_lock(request.method(), &path, workspace_id)
-            *request.method(),
+    {
-            Method::GET | Method::HEAD | Method::OPTIONS
-        ) {
         Some(api.mutation_lock(workspace_id).await.lock_owned().await)
     } else {
         None
@@ -3053,11 +3068,19 @@ fn build_inner_router(api: WorkspaceApi) -> Router {
             get(scoped_list_repository_ssh_credentials)
                 .post(scoped_create_repository_ssh_credential),
         )
+        .route(
+            "/api/w/{workspace_id}/settings/repository-access/credentials/generate",
+            post(scoped_generate_repository_ssh_credential),
+        )
         .route(
             "/api/w/{workspace_id}/settings/repository-access/credentials/{credential_id}",
             get(scoped_get_repository_ssh_credential)
                 .delete(scoped_delete_repository_ssh_credential),
         )
+        .route(
+            "/api/w/{workspace_id}/settings/repository-access/credentials/{credential_id}/public-key",
+            get(scoped_get_repository_ssh_public_key),
+        )
         .route(
             "/api/w/{workspace_id}/settings/repository-access/credentials/{credential_id}/rotate",
             post(scoped_rotate_repository_ssh_credential),
@@ -3342,6 +3365,11 @@ fn build_inner_router(api: WorkspaceApi) -> Router {
             "/api/w/{workspace_id}/repositories/{repository_key}",
             get(scoped_repository_detail),
         )
+        .route(
+            "/api/w/{workspace_id}/repositories/{repository_key}/ssh-connection-test",
+            post(scoped_probe_repository_ssh_connection)
+                .put(scoped_confirm_repository_ssh_host_trust),
+        )
         .route("/api/repositories/{repository_key}/log", get(repository_log))
         .route(
             "/api/w/{workspace_id}/repositories/{repository_key}/log",
@@ -4449,6 +4477,8 @@ async fn scoped_list_repository_ssh_credentials(
     Extension(actor): Extension<RequestActor>,
 ) -> ApiResult<Json<Vec<RepositorySshCredential>>> {
     require_manage_repository_secrets(&api, &path.workspace_id, &actor).await?;
+    api.repository_secrets
+        .ensure_workspace_default_credential(&path.workspace_id)?;
     let projection = active_repository_access_projection(&api, &path.workspace_id)?;
     Ok(Json(
         api.repository_secrets
@@ -4472,6 +4502,19 @@ async fn scoped_get_repository_ssh_credential(
     Ok(Json(credential))
 }
 
+async fn scoped_get_repository_ssh_public_key(
+    State(api): State<WorkspaceApi>,
+    AxumPath(path): AxumPath<ScopedRepositoryCredentialPath>,
+    Extension(actor): Extension<RequestActor>,
+) -> ApiResult<Json<RepositorySshPublicKey>> {
+    require_manage_repository_secrets(&api, &path.workspace_id, &actor).await?;
+    let public_key = api
+        .repository_secrets
+        .credential_public_key(&path.workspace_id, &path.credential_id)?
+        .ok_or_else(|| Error::InvalidRecordId(path.credential_id.clone()))?;
+    Ok(Json(public_key))
+}
+
 async fn scoped_create_repository_ssh_credential(
     State(api): State<WorkspaceApi>,
     AxumPath(path): AxumPath<ScopedWorkspacePath>,
@@ -4479,12 +4522,43 @@ async fn scoped_create_repository_ssh_credential(
     Json(request): Json<CreateRepositorySshCredentialRequest>,
 ) -> ApiResult<(StatusCode, Json<RepositorySshCredential>)> {
     require_manage_repository_secrets(&api, &path.workspace_id, &actor).await?;
+    if request.credential_id
+        == crate::repository_access::WORKSPACE_DEFAULT_REPOSITORY_SSH_CREDENTIAL_ID
+    {
+        return Err(Error::InvalidInput(
+            "Workspace default SSH credential id is reserved".to_string(),
+        )
+        .into());
+    }
     let credential =
         api.repository_secrets
             .create_credential(&path.workspace_id, request, &actor.account_id)?;
     Ok((StatusCode::CREATED, Json(credential)))
 }
 
+async fn scoped_generate_repository_ssh_credential(
+    State(api): State<WorkspaceApi>,
+    AxumPath(path): AxumPath<ScopedWorkspacePath>,
+    Extension(actor): Extension<RequestActor>,
+    Json(request): Json<GenerateRepositorySshCredentialRequest>,
+) -> ApiResult<(StatusCode, Json<RepositorySshCredential>)> {
+    require_manage_repository_secrets(&api, &path.workspace_id, &actor).await?;
+    if request.credential_id
+        == crate::repository_access::WORKSPACE_DEFAULT_REPOSITORY_SSH_CREDENTIAL_ID
+    {
+        return Err(Error::InvalidInput(
+            "Workspace default SSH credential id is reserved".to_string(),
+        )
+        .into());
+    }
+    let credential = api.repository_secrets.generate_credential(
+        &path.workspace_id,
+        request,
+        &actor.account_id,
+    )?;
+    Ok((StatusCode::CREATED, Json(credential)))
+}
+
 async fn scoped_rotate_repository_ssh_credential(
     State(api): State<WorkspaceApi>,
     AxumPath(path): AxumPath<ScopedRepositoryCredentialPath>,
@@ -9270,6 +9344,148 @@ async fn scoped_repository_detail(
     repository_detail(State(api), AxumPath(path.repository_key)).await
 }
 
+async fn scoped_probe_repository_ssh_connection(
+    State(api): State<WorkspaceApi>,
+    AxumPath(path): AxumPath<ScopedRepositoryPath>,
+    Extension(actor): Extension<RequestActor>,
+    Json(request): Json<RepositorySshConnectionProbeRequest>,
+) -> ApiResult<Json<RepositorySshConnectionProbeResponse>> {
+    require_manage_repository_secrets(&api, &path.workspace_id, &actor).await?;
+    require_active_workspace_runtime_binding(&api, &request.runtime_id).await?;
+    probe_repository_ssh_connection(&api, &path, &request.runtime_id).map(Json)
+}
+
+async fn scoped_confirm_repository_ssh_host_trust(
+    State(api): State<WorkspaceApi>,
+    AxumPath(path): AxumPath<ScopedRepositoryPath>,
+    Extension(actor): Extension<RequestActor>,
+    Json(request): Json<ConfirmRepositorySshHostTrustRequest>,
+) -> ApiResult<Json<RepositorySshHostTrust>> {
+    require_manage_repository_secrets(&api, &path.workspace_id, &actor).await?;
+    require_active_workspace_runtime_binding(&api, &request.runtime_id).await?;
+    let probe = probe_repository_ssh_connection(&api, &path, &request.runtime_id)?;
+    let candidate = probe
+        .candidates
+        .iter()
+        .find(|candidate| candidate.host_key == request.host_key)
+        .ok_or_else(|| {
+            settings_bad_request(
+                "repository_ssh_host_key_not_observed",
+                "Selected SSH host key was not presented by the target Runtime",
+            )
+        })?;
+    if request.expected_host_trust_revision != probe.expected_host_trust_revision {
+        return Err(ApiError::from(Error::WorkspaceConfigConflict(
+            "SSH host trust revision changed after the connection test".to_string(),
+        )));
+    }
+    let host_trust = api.repository_secrets.put_host_trust(
+        &path.workspace_id,
+        PutRepositorySshHostTrustRequest {
+            operation_id: request.operation_id,
+            host_trust_id: probe.host_trust_id,
+            hostname: probe.hostname,
+            port: probe.port,
+            host_key: candidate.host_key.clone(),
+            expected_revision: probe.expected_host_trust_revision,
+        },
+        &actor.account_id,
+    )?;
+    Ok(Json(host_trust))
+}
+
+fn repository_ssh_connection_trust_state(
+    candidates: &[RepositorySshHostKeyCandidate],
+    existing_fingerprint: Option<&str>,
+) -> RepositorySshConnectionTrustState {
+    match existing_fingerprint {
+        None => RepositorySshConnectionTrustState::Untrusted,
+        Some(fingerprint)
+            if candidates
+                .iter()
+                .any(|candidate| candidate.fingerprint == fingerprint) =>
+        {
+            RepositorySshConnectionTrustState::Verified
+        }
+        Some(_) => RepositorySshConnectionTrustState::Changed,
+    }
+}
+
+fn probe_repository_ssh_connection(
+    api: &WorkspaceApi,
+    path: &ScopedRepositoryPath,
+    runtime_id: &str,
+) -> ApiResult<RepositorySshConnectionProbeResponse> {
+    validate_workspace_scope(api, &path.workspace_id)?;
+    let repository = api.require_configured_workspace_repository_by_key(&path.repository_key)?;
+    let (hostname, port) = crate::repository_access::repository_ssh_endpoint(
+        &path.repository_key,
+        &repository.source.uri,
+    )?
+    .ok_or_else(|| {
+        settings_bad_request(
+            "repository_ssh_connection_test_not_applicable",
+            "Repository does not use an SSH source",
+        )
+    })?;
+    let observed = api
+        .runtime
+        .probe_ssh_host_keys(
+            runtime_id,
+            worker_runtime::ssh_host_key_probe::SshHostKeyProbeRequest {
+                hostname: hostname.clone(),
+                port,
+            },
+        )
+        .map_err(|error| error.into_error())?;
+    let candidates = observed
+        .candidates
+        .into_iter()
+        .map(|candidate| RepositorySshHostKeyCandidate {
+            algorithm: candidate.algorithm,
+            host_key: candidate.public_key,
+            fingerprint: candidate.fingerprint,
+        })
+        .collect::<Vec<_>>();
+    if candidates.is_empty() {
+        return Err(settings_bad_request(
+            "repository_ssh_host_key_not_observed",
+            "Target Runtime did not observe an SSH Ed25519 host key",
+        ));
+    }
+    let matches =
+        api.repository_secrets
+            .host_trusts_for_endpoint(&path.workspace_id, &hostname, port)?;
+    if matches.len() > 1 {
+        return Err(ApiError::from(Error::WorkspaceConfigConflict(
+            "Multiple SSH host trust records match this Repository endpoint".to_string(),
+        )));
+    }
+    let existing = matches.first();
+    let trust_state = repository_ssh_connection_trust_state(
+        &candidates,
+        existing.map(|host_trust| host_trust.fingerprint.as_str()),
+    );
+    Ok(RepositorySshConnectionProbeResponse {
+        workspace_id: path.workspace_id.clone(),
+        repository_key: path.repository_key.clone(),
+        runtime_id: runtime_id.to_string(),
+        hostname: hostname.clone(),
+        port,
+        trust_state,
+        host_trust_id: existing.map_or_else(
+            || {
+                crate::repository_access::RepositorySecretService::automatic_host_trust_id(
+                    &hostname, port,
+                )
+            },
+            |host_trust| host_trust.host_trust_id.clone(),
+        ),
+        expected_host_trust_revision: existing.map(|host_trust| host_trust.current_revision),
+        candidates,
+    })
+}
+
 async fn scoped_repository_log(
     State(api): State<WorkspaceApi>,
     AxumPath(path): AxumPath<ScopedRepositoryPath>,
@@ -10921,12 +11137,31 @@ fn working_directory_detail_for_runtime(
     runtime_id: &str,
     working_directory_id: &str,
 ) -> ApiResult<Json<BrowserWorkingDirectoryDetailResponse>> {
+    let existing = api
+        .store
+        .get_workdir_registry(&api.config.workspace_id, working_directory_id)?
+        .ok_or_else(|| {
+            ApiError::with_diagnostics(
+                Error::RuntimeOperationFailed {
+                    runtime_id: "workspace-backend".to_string(),
+                    code: "working_directory_not_found".to_string(),
+                    message: format!("Unknown Workdir `{working_directory_id}`"),
+                },
+                Vec::new(),
+            )
+        })?;
+    if existing.runtime_id != runtime_id {
+        return Err(ApiError::from(Error::WorkspacePermissionDenied(
+            "Workdir does not belong to the requested Runtime".to_string(),
+        )));
+    }
     let result = api
         .runtime
         .working_directory(runtime_id, working_directory_id)
         .map_err(|err| err.into_error())?;
     if let Some(working_directory) = result.working_directory {
-        let record = workdir_record_from_summary(&api, runtime_id, &working_directory.summary);
+        let mut record = workdir_record_from_summary(&api, runtime_id, &working_directory.summary);
+        preserve_workdir_identity_for_corrupted_summary(&mut record, Some(&existing));
         api.store.upsert_workdir_registry(&record)?;
         let summary = projected_workdir_summary_from_record(&api, &record)?;
         return Ok(Json(BrowserWorkingDirectoryDetailResponse {
@@ -10936,25 +11171,12 @@ fn working_directory_detail_for_runtime(
             diagnostics: working_directory_diagnostics(result.diagnostics),
         }));
     }
-    if let Some(record) = api
+    Ok(Json(BrowserWorkingDirectoryDetailResponse {
-        .store
-        .get_workdir_registry(&api.config.workspace_id, working_directory_id)?
-    {
-        return Ok(Json(BrowserWorkingDirectoryDetailResponse {
         workspace_id: api.config.workspace_id.clone(),
         runtime_id: runtime_id.to_string(),
-            item: projected_workdir_summary_from_record(&api, &record)?,
+        item: projected_workdir_summary_from_record(&api, &existing)?,
         diagnostics: working_directory_diagnostics(result.diagnostics),
-        }));
+    }))
-    }
-    Err(ApiError::with_diagnostics(
-        Error::RuntimeOperationFailed {
-            runtime_id: runtime_id.to_string(),
-            code: "workspace_working_directory_lookup_failed".to_string(),
-            message: "Runtime did not return working directory".to_string(),
-        },
-        result.diagnostics,
-    ))
 }
 
 fn workdir_removal_response(
@@ -14555,6 +14777,7 @@ fn backend_resource_error_status(error: &BackendResourceError) -> StatusCode {
         | BackendResourceError::Oversized { .. }
         | BackendResourceError::ContentTypeMismatch { .. }
         | BackendResourceError::InvalidResponse { .. } => StatusCode::BAD_REQUEST,
+        BackendResourceError::Timeout => StatusCode::GATEWAY_TIMEOUT,
         BackendResourceError::Transport { .. } => StatusCode::BAD_GATEWAY,
     }
 }
@@ -16904,6 +17127,35 @@ fn upsert_pending_backend_workdir(
     Ok(workdir_id)
 }
 
+fn reconcile_runtime_workdir_observations(
+    api: &WorkspaceApi,
+    runtime_id: &str,
+    items: &[worker_runtime::catalog::WorkingDirectoryStatus],
+) -> ApiResult<std::collections::BTreeSet<String>> {
+    let mut observed = std::collections::BTreeSet::new();
+    for status in items {
+        let Some(existing) = api.store.get_workdir_registry(
+            &api.config.workspace_id,
+            &status.summary.working_directory_id,
+        )?
+        else {
+            continue;
+        };
+        if existing.runtime_id != runtime_id {
+            continue;
+        }
+        observed.insert(status.summary.working_directory_id.clone());
+        if status.summary.status == WorkingDirectoryStatusKind::NotFound {
+            persist_workdir_not_found(api, existing)?;
+            continue;
+        }
+        let mut record = workdir_record_from_summary(api, runtime_id, &status.summary);
+        preserve_workdir_identity_for_corrupted_summary(&mut record, Some(&existing));
+        api.store.upsert_workdir_registry(&record)?;
+    }
+    Ok(observed)
+}
+
 fn sync_runtime_workdir_observations(
     api: &WorkspaceApi,
     runtime_id: &str,
@@ -16912,26 +17164,7 @@ fn sync_runtime_workdir_observations(
         .runtime
         .list_working_directories(runtime_id)
         .map_err(|err| err.into_error())?;
-    let mut observed = std::collections::BTreeSet::new();
+    let observed = reconcile_runtime_workdir_observations(api, runtime_id, &response.items)?;
-    for status in &response.items {
-        observed.insert(status.summary.working_directory_id.clone());
-        if status.summary.status == WorkingDirectoryStatusKind::NotFound {
-            if let Some(record) = api.store.get_workdir_registry(
-                &api.config.workspace_id,
-                &status.summary.working_directory_id,
-            )? {
-                persist_workdir_not_found(api, record)?;
-            }
-            continue;
-        }
-        let existing = api.store.get_workdir_registry(
-            &api.config.workspace_id,
-            &status.summary.working_directory_id,
-        )?;
-        let mut record = workdir_record_from_summary(api, runtime_id, &status.summary);
-        preserve_workdir_identity_for_corrupted_summary(&mut record, existing.as_ref());
-        api.store.upsert_workdir_registry(&record)?;
-    }
     for mut record in api
         .store
         .list_workdir_registry(&api.config.workspace_id, 500)?
@@ -17295,6 +17528,30 @@ fn validate_working_directory_claim_for_browser(
     Ok(())
 }
 
+fn repository_ssh_lease_candidates(
+    api: &WorkspaceApi,
+    primary: crate::repository_access::LeasedRepositorySshAccess,
+) -> ApiResult<Vec<crate::repository_access::LeasedRepositorySshAccess>> {
+    let workspace_default = api
+        .repository_secrets
+        .ensure_workspace_default_credential(&api.config.workspace_id)?;
+    if primary.credential_id
+        == crate::repository_access::WORKSPACE_DEFAULT_REPOSITORY_SSH_CREDENTIAL_ID
+    {
+        return Ok(vec![primary]);
+    }
+    let workspace_default = api
+        .repository_secrets
+        .lease_ssh_materialization_access_revision(
+            &api.config.workspace_id,
+            crate::repository_access::WORKSPACE_DEFAULT_REPOSITORY_SSH_CREDENTIAL_ID,
+            workspace_default.current_revision,
+            &primary.host_trust_id,
+            primary.host_trust_revision,
+        )?;
+    Ok(vec![primary, workspace_default])
+}
+
 fn authorize_repository_materialization_operation(
     api: &WorkspaceApi,
     operation: &WorkdirCreateOperationRecord,
@@ -17324,6 +17581,16 @@ fn authorize_repository_materialization_operation(
                     host_trust_id,
                     host_trust_revision,
                 )?;
+            let leases = repository_ssh_lease_candidates(api, lease)?;
+            let primary_lease = leases.first().ok_or_else(|| {
+                settings_bad_request(
+                    "working_directory_repository_access_invalid",
+                    "Repository SSH access has no credential candidates",
+                )
+            })?;
+            let primary_host_trust_id = primary_lease.host_trust_id.clone();
+            let primary_host_trust_revision = primary_lease.host_trust_revision;
+            let known_hosts_entry = primary_lease.known_hosts_entry.clone();
             let access = match access_mode {
                 "read_only" => workspace_api::RepositoryAccessMode::ReadOnly,
                 "read_write" => workspace_api::RepositoryAccessMode::ReadWrite,
@@ -17342,13 +17609,30 @@ fn authorize_repository_materialization_operation(
                     &operation.resolved_runtime_id,
                     format!("repository-ssh-access:{}", operation.operation_id),
                     format!(
-                        "credential:{}:host-trust:{}",
+                        "credentials:{}:host-trust:{}",
-                        lease.credential_revision, lease.host_trust_revision
+                        leases
+                            .iter()
+                            .map(|lease| format!(
+                                "{}:{}",
+                                lease.credential_id, lease.credential_revision
+                            ))
+                            .collect::<Vec<_>>()
+                            .join(","),
+                        primary_host_trust_revision
                     ),
                     i64::try_from(expires_at_epoch_seconds).unwrap_or(i64::MAX),
                     worker_runtime::resource::RepositorySshAccessSecret {
+                        credential_candidates: leases
+                            .iter()
+                            .map(|lease| {
+                                worker_runtime::resource::RepositorySshAccessSecretCandidate {
+                                    credential_id: lease.credential_id.clone(),
+                                    credential_revision: lease.credential_revision,
                                     private_key: lease.private_key.as_str().to_string(),
-                        known_hosts_entry: lease.known_hosts_entry.clone(),
+                                }
+                            })
+                            .collect(),
+                        known_hosts_entry: known_hosts_entry.clone(),
                     },
                 )
                 .map_err(|_| {
@@ -17365,17 +17649,22 @@ fn authorize_repository_materialization_operation(
                 config_projection_digest: operation.config_projection_digest.clone(),
                 cache_generation: operation.cache_generation,
                 ssh: Some(RepositorySshMaterializationAccess {
+                    credential_candidates: leases
+                        .into_iter()
+                        .map(|lease| RepositorySshCredentialCandidate {
                             credential_id: lease.credential_id,
                             credential_revision: lease.credential_revision,
-                    host_trust_id: lease.host_trust_id,
+                            private_key: SensitiveString::default(),
-                    host_trust_revision: lease.host_trust_revision,
+                        })
+                        .collect(),
+                    host_trust_id: primary_host_trust_id,
+                    host_trust_revision: primary_host_trust_revision,
                     access,
                     expires_at_epoch_seconds,
                     repository_id: request.repository.id.clone(),
                     repository_source_fingerprint: request.repository.source_fingerprint.clone(),
                     repository_uri: request.repository.source.uri.clone(),
                     secret_resource,
-                    private_key: SensitiveString::default(),
                     known_hosts_entry: SensitiveString::default(),
                 }),
             }
@@ -17408,12 +17697,18 @@ fn authorize_repository_materialization_operation(
                     "SSH Repository access authority is unavailable",
                 )
             })?;
+            let primary_credential = ssh.credential_candidates.first().ok_or_else(|| {
+                settings_bad_request(
+                    "working_directory_repository_access_invalid",
+                    "Repository SSH access has no credential candidates",
+                )
+            })?;
             api.config_store.bind_workdir_create_repository_access(
                 &api.config.workspace_id,
                 &operation.operation_id,
                 request_fingerprint,
-                &ssh.credential_id,
+                &primary_credential.credential_id,
-                ssh.credential_revision,
+                primary_credential.credential_revision,
                 &ssh.host_trust_id,
                 ssh.host_trust_revision,
                 match ssh.access {
@@ -17473,19 +17768,40 @@ fn authorize_repository_materialization(
         .map(|repository| repository.repository_key.as_str())
         .ok_or_else(|| Error::UnknownRepository(request.repository.id.clone()))?;
     let ssh = if request.repository.source.kind == workspace_api::RepositorySourceKind::Ssh {
-        let binding = projection
+        let binding = match projection
             .bindings
             .iter()
             .find(|binding| binding.repository_key == repository_key)
+            .cloned()
+        {
+            Some(binding) => binding,
+            None => api
+                .repository_secrets
+                .default_ssh_binding_for_repository(
+                    &api.config.workspace_id,
+                    repository_key,
+                    &request.repository.source.uri,
+                )?
                 .ok_or_else(|| {
                     settings_bad_request(
-                    "working_directory_remote_repository_access_required",
+                        "working_directory_remote_repository_host_trust_required",
-                    "SSH Repository has no active Workspace credential and host-trust binding",
+                        "SSH Repository has no pinned host trust matching its URI",
                     )
-            })?;
+                })?,
+        };
         let lease = api
             .repository_secrets
-            .lease_ssh_materialization_access(&api.config.workspace_id, binding)?;
+            .lease_ssh_materialization_access(&api.config.workspace_id, &binding)?;
+        let leases = repository_ssh_lease_candidates(api, lease)?;
+        let primary_lease = leases.first().ok_or_else(|| {
+            settings_bad_request(
+                "working_directory_repository_access_invalid",
+                "Repository SSH access has no credential candidates",
+            )
+        })?;
+        let primary_host_trust_id = primary_lease.host_trust_id.clone();
+        let primary_host_trust_revision = primary_lease.host_trust_revision;
+        let known_hosts_entry = primary_lease.known_hosts_entry.clone();
         let expires_at_epoch_seconds = repository_access_expiry();
         let secret_resource = api
             .resource_broker
@@ -17494,13 +17810,30 @@ fn authorize_repository_materialization(
                 runtime_id,
                 format!("repository-ssh-access:{operation_id}"),
                 format!(
-                    "credential:{}:host-trust:{}",
+                    "credentials:{}:host-trust:{}",
-                    lease.credential_revision, lease.host_trust_revision
+                    leases
+                        .iter()
+                        .map(|lease| format!(
+                            "{}:{}",
+                            lease.credential_id, lease.credential_revision
+                        ))
+                        .collect::<Vec<_>>()
+                        .join(","),
+                    primary_host_trust_revision
                 ),
                 i64::try_from(expires_at_epoch_seconds).unwrap_or(i64::MAX),
                 worker_runtime::resource::RepositorySshAccessSecret {
+                    credential_candidates: leases
+                        .iter()
+                        .map(
+                            |lease| worker_runtime::resource::RepositorySshAccessSecretCandidate {
+                                credential_id: lease.credential_id.clone(),
+                                credential_revision: lease.credential_revision,
                                 private_key: lease.private_key.as_str().to_string(),
-                    known_hosts_entry: lease.known_hosts_entry.clone(),
+                            },
+                        )
+                        .collect(),
+                    known_hosts_entry: known_hosts_entry.clone(),
                 },
             )
             .map_err(|_| {
@@ -17510,17 +17843,22 @@ fn authorize_repository_materialization(
                 )
             })?;
         Some(RepositorySshMaterializationAccess {
+            credential_candidates: leases
+                .into_iter()
+                .map(|lease| RepositorySshCredentialCandidate {
                     credential_id: lease.credential_id,
                     credential_revision: lease.credential_revision,
-            host_trust_id: lease.host_trust_id,
+                    private_key: SensitiveString::default(),
-            host_trust_revision: lease.host_trust_revision,
+                })
+                .collect(),
+            host_trust_id: primary_host_trust_id,
+            host_trust_revision: primary_host_trust_revision,
             access: binding.access,
             expires_at_epoch_seconds,
             repository_id: request.repository.id.clone(),
             repository_source_fingerprint: request.repository.source_fingerprint.clone(),
             repository_uri: request.repository.source.uri.clone(),
             secret_resource,
-            private_key: SensitiveString::default(),
             known_hosts_entry: SensitiveString::default(),
         })
     } else {
@@ -18151,6 +18489,14 @@ mod tests {
         SqliteWorkspaceStore, UserRecord, WorkspaceRecord, WorkspaceRuntimeBinding,
     };
 
+    #[test]
+    fn backend_resource_timeout_maps_to_gateway_timeout() {
+        assert_eq!(
+            backend_resource_error_status(&BackendResourceError::Timeout),
+            StatusCode::GATEWAY_TIMEOUT
+        );
+    }
+
     #[test]
     fn browser_worker_console_href_uses_logical_worker_route() {
         let href = browser_worker_console_href("workspace/one", "W-7");
@@ -18158,6 +18504,25 @@ mod tests {
         assert!(!href.contains("/runtimes/"));
     }
 
+    #[test]
+    fn runtime_resource_fetch_bypasses_workspace_mutation_lock() {
+        assert!(!workspace_request_requires_mutation_lock(
+            &Method::POST,
+            "/api/runtime/v1/workspaces/workspace-a/resources/fetch",
+            "workspace-a"
+        ));
+        assert!(workspace_request_requires_mutation_lock(
+            &Method::POST,
+            "/api/w/workspace-a/working-directories",
+            "workspace-a"
+        ));
+        assert!(!workspace_request_requires_mutation_lock(
+            &Method::GET,
+            "/api/w/workspace-a/working-directories",
+            "workspace-a"
+        ));
+    }
+
     #[tokio::test]
     async fn workspace_mutation_gate_serializes_deletion_with_active_mutations() {
         let locks = Arc::new(AsyncMutex::new(HashMap::new()));
@@ -19161,6 +19526,106 @@ mod tests {
         );
     }
 
+    #[test]
+    fn repository_ssh_probe_distinguishes_untrusted_verified_and_changed_keys() {
+        let candidates = vec![RepositorySshHostKeyCandidate {
+            algorithm: "ssh-ed25519".to_string(),
+            host_key: "ssh-ed25519 AAAA".to_string(),
+            fingerprint: "SHA256:observed".to_string(),
+        }];
+
+        assert_eq!(
+            repository_ssh_connection_trust_state(&candidates, None),
+            RepositorySshConnectionTrustState::Untrusted
+        );
+        assert_eq!(
+            repository_ssh_connection_trust_state(&candidates, Some("SHA256:observed")),
+            RepositorySshConnectionTrustState::Verified
+        );
+        assert_eq!(
+            repository_ssh_connection_trust_state(&candidates, Some("SHA256:old")),
+            RepositorySshConnectionTrustState::Changed
+        );
+    }
+
+    #[tokio::test]
+    async fn repository_ssh_clone_leases_specific_then_workspace_default_credentials() {
+        let dir = tempfile::tempdir().unwrap();
+        let api = test_api(dir.path()).await;
+        let specific = api
+            .repository_secrets
+            .generate_credential(
+                &api.config.workspace_id,
+                GenerateRepositorySshCredentialRequest {
+                    operation_id: "generate-repository-specific".to_string(),
+                    credential_id: "repository-specific".to_string(),
+                    name: "Repository specific".to_string(),
+                },
+                "owner-account",
+            )
+            .unwrap();
+        let host_public_key = api
+            .repository_secrets
+            .credential_public_key(&api.config.workspace_id, &specific.credential_id)
+            .unwrap()
+            .unwrap()
+            .public_key;
+        let host_trust = api
+            .repository_secrets
+            .put_host_trust(
+                &api.config.workspace_id,
+                PutRepositorySshHostTrustRequest {
+                    operation_id: "trust-example-host".to_string(),
+                    host_trust_id: "example-host".to_string(),
+                    hostname: "example.test".to_string(),
+                    port: 22,
+                    host_key: host_public_key,
+                    expected_revision: None,
+                },
+                "owner-account",
+            )
+            .unwrap();
+        let binding = workspace_api::RepositorySshAccessBinding {
+            repository_key: "test-repository".to_string(),
+            credential_id: specific.credential_id.clone(),
+            host_trust_id: host_trust.host_trust_id,
+            access: workspace_api::RepositoryAccessMode::ReadOnly,
+        };
+        let primary = api
+            .repository_secrets
+            .lease_ssh_materialization_access(&api.config.workspace_id, &binding)
+            .unwrap();
+
+        let candidates = repository_ssh_lease_candidates(&api, primary).unwrap();
+
+        assert_eq!(candidates.len(), 2);
+        assert_eq!(candidates[0].credential_id, "repository-specific");
+        assert_eq!(
+            candidates[1].credential_id,
+            crate::repository_access::WORKSPACE_DEFAULT_REPOSITORY_SSH_CREDENTIAL_ID
+        );
+        assert_ne!(
+            candidates[0].private_key.as_str(),
+            candidates[1].private_key.as_str()
+        );
+        assert_eq!(
+            candidates[0].known_hosts_entry,
+            candidates[1].known_hosts_entry
+        );
+
+        let default_binding = workspace_api::RepositorySshAccessBinding {
+            credential_id: crate::repository_access::WORKSPACE_DEFAULT_REPOSITORY_SSH_CREDENTIAL_ID
+                .to_string(),
+            ..binding
+        };
+        let primary_default = api
+            .repository_secrets
+            .lease_ssh_materialization_access(&api.config.workspace_id, &default_binding)
+            .unwrap();
+        let default_only = repository_ssh_lease_candidates(&api, primary_default).unwrap();
+        assert_eq!(default_only.len(), 1);
+    }
+
     #[tokio::test]
     async fn repository_bound_ticket_flow_and_workdir_launches_fail_closed_across_workspaces() {
         let dir = tempfile::tempdir().unwrap();
@@ -19270,7 +19735,13 @@ mod tests {
                 "1",
                 i64::MAX,
                 worker_runtime::resource::RepositorySshAccessSecret {
+                    credential_candidates: vec![
+                        worker_runtime::resource::RepositorySshAccessSecretCandidate {
+                            credential_id: "credential-1".to_string(),
+                            credential_revision: 1,
                             private_key: "private-key-bytes".to_string(),
+                        },
+                    ],
                     known_hosts_entry: "known-hosts-entry".to_string(),
                 },
             )
@@ -19290,8 +19761,13 @@ mod tests {
                 cache_generation: 0,
                 ssh: Some(
                     worker_runtime::catalog::RepositorySshMaterializationAccess {
+                        credential_candidates: vec![
+                            worker_runtime::catalog::RepositorySshCredentialCandidate {
                                 credential_id: "credential-1".to_string(),
                                 credential_revision: 1,
+                                private_key: worker_runtime::catalog::SensitiveString::default(),
+                            },
+                        ],
                         host_trust_id: "host-trust-1".to_string(),
                         host_trust_revision: 1,
                         access: workspace_api::RepositoryAccessMode::ReadOnly,
@@ -19303,7 +19779,6 @@ mod tests {
                             .clone(),
                         repository_uri: working_directory.repository.source.uri.clone(),
                         secret_resource,
-                        private_key: worker_runtime::catalog::SensitiveString::default(),
                         known_hosts_entry: worker_runtime::catalog::SensitiveString::default(),
                     },
                 ),
@@ -21007,6 +21482,60 @@ mod tests {
         assert_eq!(response.status(), StatusCode::NOT_FOUND);
     }
 
+    #[tokio::test]
+    async fn runtime_workdir_inventory_does_not_adopt_unknown_workspace_rows() {
+        let dir = tempfile::tempdir().unwrap();
+        let api = test_api(dir.path()).await;
+        let foreign = WorkdirRegistryRecord {
+            workspace_id: "other-workspace".to_string(),
+            workdir_id: "foreign-workdir".to_string(),
+            runtime_id: EMBEDDED_WORKER_RUNTIME_ID.to_string(),
+            repository_id: "foreign-repository".to_string(),
+            creation_selector: None,
+            creation_ref: None,
+            creation_tree: None,
+            current_selector: None,
+            current_ref: None,
+            current_tree: None,
+            observed_at_epoch_seconds: None,
+            materialization_status: "present".to_string(),
+            cleanliness: "clean".to_string(),
+            created_at: "1".to_string(),
+            updated_at: "1".to_string(),
+        };
+        let items = [worker_runtime::catalog::WorkingDirectoryStatus {
+            summary: runtime_workdir_summary_from_record(&foreign),
+        }];
+
+        let observed =
+            reconcile_runtime_workdir_observations(&api, EMBEDDED_WORKER_RUNTIME_ID, &items)
+                .unwrap();
+
+        assert!(observed.is_empty());
+        assert!(
+            api.store
+                .get_workdir_registry(TEST_WORKSPACE_ID, "foreign-workdir")
+                .unwrap()
+                .is_none()
+        );
+    }
+
+    #[tokio::test]
+    async fn runtime_workdir_detail_rejects_unknown_workspace_row() {
+        let dir = tempfile::tempdir().unwrap();
+        let api = test_api(dir.path()).await;
+
+        let response = working_directory_detail_for_runtime(
+            api,
+            EMBEDDED_WORKER_RUNTIME_ID,
+            "foreign-workdir",
+        )
+        .unwrap_err()
+        .into_response();
+
+        assert_eq!(response.status(), StatusCode::BAD_REQUEST);
+    }
+
     #[test]
     fn runtime_binding_summary_omits_stale_verification_revision() {
         let binding = WorkspaceRuntimeBinding {

web/workspace/deno.json

@@ -6,7 +6,7 @@
     "dev": "deno run -A npm:vite@7.2.7 dev",
     "dev:backend": "cd ../.. && cargo run -p yoi-workspace-server --bin yoi-server -- serve --listen 127.0.0.1:8787",
     "check": "deno run -A npm:@sveltejs/kit@2.49.4 sync && deno run -A npm:svelte-check@4.3.4 --tsconfig ./tsconfig.json",
-    "test": "deno test --allow-read=src,test,tests --allow-env=LOG,VSCODE_TEXTMATE_DEBUG,NODE_ENV tests/workspace-model.test.ts tests/workspace-catalog.test.ts tests/profile-api.test.ts tests/skill-api.test.ts src/lib/workspace/auth/model.test.ts tests/auth-api.test.ts src/lib/workspace/api/http.test.ts src/lib/workspace/api/workers.test.ts src/lib/workspace/header/breadcrumb-model.test.ts src/lib/workspace/console/chat-submit.test.ts src/lib/workspace/console/composer-delivery.test.ts test/composer-history.test.ts tests/composer-paste.test.ts src/lib/workspace/console/composer-command.test.ts src/lib/workspace/console/composer-draft.test.ts src/lib/workspace/console/composer-completion.test.ts src/lib/workspace/console/markdown.test.ts test/console/ansi.test.ts src/lib/workspace/console/model.test.ts src/lib/workspace/companion/api.test.ts tests/workdir-api.test.ts src/lib/workspace/console/tasks.test.ts test/ticket-detail-route-reuse.test.ts test/repositories/ui.test.ts src/lib/workspace/console/worker-console.ui.test.ts src/lib/workspace/settings/model.test.ts tests/runtime-connection.test.ts tests/runtime-management.test.ts tests/runtime-management-source.test.ts src/lib/workspace/sidebar/override-stack.test.ts src/lib/workspace/sidebar/workers.test.ts src/lib/workspace/sidebar/workspace-switcher.test.ts src/lib/workspace/sidebar/worker-subscription.test.ts src/lib/workspace/sidebar/worker-launch.test.ts test/sidebar/worker-actions.test.ts src/lib/workspace/tickets/merge-request-resources.test.ts src/lib/workspace/tickets/ticket-panel.test.ts test/merge-request-status.test.ts test/config-source/decodal-grammar.test.ts test/config-source/editor-state.test.ts test/config-source/fixed-schema-wrapper.test.ts test/config-source/toolchain.test.ts test/config-source/wasm-parity.test.ts test/repository-access/api.test.ts test/repository-access/loader.test.ts test/repository-access/ui.test.ts",
+    "test": "deno test --allow-read=src,test,tests --allow-env=LOG,VSCODE_TEXTMATE_DEBUG,NODE_ENV tests/workspace-model.test.ts tests/workspace-catalog.test.ts tests/profile-api.test.ts tests/skill-api.test.ts src/lib/workspace/auth/model.test.ts tests/auth-api.test.ts src/lib/workspace/api/http.test.ts src/lib/workspace/api/workers.test.ts src/lib/workspace/header/breadcrumb-model.test.ts src/lib/workspace/console/chat-submit.test.ts src/lib/workspace/console/composer-delivery.test.ts test/composer-history.test.ts tests/composer-paste.test.ts src/lib/workspace/console/composer-command.test.ts src/lib/workspace/console/composer-draft.test.ts src/lib/workspace/console/composer-completion.test.ts src/lib/workspace/console/markdown.test.ts test/console/ansi.test.ts src/lib/workspace/console/model.test.ts src/lib/workspace/companion/api.test.ts tests/workdir-api.test.ts src/lib/workspace/console/tasks.test.ts test/ticket-detail-route-reuse.test.ts test/repositories/ui.test.ts src/lib/workspace/console/worker-console.ui.test.ts src/lib/workspace/settings/model.test.ts tests/runtime-connection.test.ts tests/runtime-management.test.ts tests/runtime-management-source.test.ts src/lib/workspace/sidebar/override-stack.test.ts src/lib/workspace/sidebar/workers.test.ts src/lib/workspace/sidebar/workspace-switcher.test.ts src/lib/workspace/sidebar/worker-subscription.test.ts src/lib/workspace/sidebar/worker-launch.test.ts test/sidebar/worker-actions.test.ts src/lib/workspace/tickets/merge-request-resources.test.ts src/lib/workspace/tickets/ticket-panel.test.ts test/merge-request-status.test.ts test/config-source/decodal-grammar.test.ts test/config-source/editor-state.test.ts test/config-source/fixed-schema-wrapper.test.ts test/config-source/toolchain.test.ts test/config-source/wasm-parity.test.ts test/repository-access/api.test.ts test/repository-access/loader.test.ts test/repository-access/ui.test.ts test/repository-ssh-connection-ui.test.ts",
     "build": "deno run -A npm:vite@7.2.7 build",
     "preview": "deno run -A npm:vite@7.2.7 preview"
   },

web/workspace/src/lib/generated/repository-access-api.ts

@@ -22,6 +22,20 @@ export type CreateRepositorySshCredentialRequest = {
   passphrase: string | null;
 };
 
+export type GenerateRepositorySshCredentialRequest = {
+  operation_id: string;
+  credential_id: string;
+  name: string;
+};
+
+export type RepositorySshPublicKey = {
+  credential_id: string;
+  current_revision: number;
+  public_key_algorithm: string;
+  public_key_fingerprint: string;
+  public_key: string;
+};
+
 export type RotateRepositorySshCredentialRequest = {
   operation_id: string;
   expected_revision: number;

web/workspace/src/lib/generated/workspace-api.ts

@@ -307,6 +307,38 @@ export type RepositoryDetailResponse = {
   source: string;
 };
 
+export type RepositorySshConnectionProbeRequest = { runtime_id: string };
+
+export type RepositorySshHostKeyCandidate = {
+  algorithm: string;
+  host_key: string;
+  fingerprint: string;
+};
+
+export type RepositorySshConnectionTrustState =
+  | "untrusted"
+  | "verified"
+  | "changed";
+
+export type RepositorySshConnectionProbeResponse = {
+  workspace_id: string;
+  repository_key: string;
+  runtime_id: string;
+  hostname: string;
+  port: number;
+  trust_state: RepositorySshConnectionTrustState;
+  host_trust_id: string;
+  expected_host_trust_revision: number | null;
+  candidates: Array<RepositorySshHostKeyCandidate>;
+};
+
+export type ConfirmRepositorySshHostTrustRequest = {
+  operation_id: string;
+  runtime_id: string;
+  host_key: string;
+  expected_host_trust_revision: number | null;
+};
+
 export type RepositoryLogResponse = {
   workspace_id: string;
   repository_key: string;

web/workspace/src/lib/workspace/api/repository-access.ts

@@ -2,6 +2,7 @@ import type {
   RepositoryAccessProjection,
   RepositorySshCredential,
   RepositorySshHostTrust,
+  RepositorySshPublicKey,
 } from "../../generated/repository-access-api.ts";
 
 export class RepositoryAccessSchemaError extends Error {
@@ -50,6 +51,25 @@ export function parseRepositorySshCredential(
   return record as RepositorySshCredential;
 }
 
+export function parseRepositorySshPublicKey(
+  value: unknown,
+  path = "public_key",
+): RepositorySshPublicKey {
+  const record = readRecord(value, path, [
+    "credential_id",
+    "current_revision",
+    "public_key_algorithm",
+    "public_key_fingerprint",
+    "public_key",
+  ]);
+  readString(record, "credential_id", path);
+  readRevision(record, "current_revision", path);
+  readString(record, "public_key_algorithm", path);
+  readString(record, "public_key_fingerprint", path);
+  readString(record, "public_key", path);
+  return record as RepositorySshPublicKey;
+}
+
 export function parseRepositorySshHostTrusts(
   value: unknown,
 ): RepositorySshHostTrust[] {

web/workspace/src/lib/workspace/api/workspace-model.ts

@@ -10,6 +10,9 @@ import type {
   RepositoryLogResponse,
   RepositorySource,
   RepositorySourceKind,
+  RepositorySshConnectionProbeResponse,
+  RepositorySshConnectionTrustState,
+  RepositorySshHostKeyCandidate,
   RepositorySummary,
   WorkspaceAuthConfig,
   WorkspaceCatalogListResponse,
@@ -35,6 +38,8 @@ export type {
   RepositoryDetailResponse,
   RepositoryListResponse,
   RepositoryLogResponse,
+  RepositorySshConnectionProbeResponse,
+  RepositorySshHostKeyCandidate,
   RepositorySummary,
   WorkspaceCatalogListResponse,
   WorkspaceCreateResponse,
@@ -583,6 +588,98 @@ export function parseRepositoryDetailResponse(
   };
 }
 
+const SSH_CONNECTION_TRUST_STATES = new Set<RepositorySshConnectionTrustState>([
+  "untrusted",
+  "verified",
+  "changed",
+]);
+
+function repositorySshHostKeyCandidate(
+  value: unknown,
+  path: string,
+): RepositorySshHostKeyCandidate {
+  const candidate = object(value, path);
+  exactKeys(candidate, ["algorithm", "host_key", "fingerprint"], path);
+  return {
+    algorithm: string(candidate.algorithm, `${path}.algorithm`),
+    host_key: string(candidate.host_key, `${path}.host_key`),
+    fingerprint: string(candidate.fingerprint, `${path}.fingerprint`),
+  };
+}
+
+export function parseRepositorySshConnectionProbeResponse(
+  value: unknown,
+): RepositorySshConnectionProbeResponse {
+  const response = object(value, "repository SSH connection probe response");
+  exactKeys(
+    response,
+    [
+      "workspace_id",
+      "repository_key",
+      "runtime_id",
+      "hostname",
+      "port",
+      "trust_state",
+      "host_trust_id",
+      "expected_host_trust_revision",
+      "candidates",
+    ],
+    "repository SSH connection probe response",
+  );
+  const trustState = string(
+    response.trust_state,
+    "repository SSH connection probe response.trust_state",
+  ) as RepositorySshConnectionTrustState;
+  if (!SSH_CONNECTION_TRUST_STATES.has(trustState)) {
+    throw new Error(
+      "repository SSH connection probe response.trust_state is invalid",
+    );
+  }
+  return {
+    workspace_id: string(
+      response.workspace_id,
+      "repository SSH connection probe response.workspace_id",
+    ),
+    repository_key: string(
+      response.repository_key,
+      "repository SSH connection probe response.repository_key",
+    ),
+    runtime_id: string(
+      response.runtime_id,
+      "repository SSH connection probe response.runtime_id",
+    ),
+    hostname: string(
+      response.hostname,
+      "repository SSH connection probe response.hostname",
+    ),
+    port: integer(
+      response.port,
+      "repository SSH connection probe response.port",
+    ),
+    trust_state: trustState,
+    host_trust_id: string(
+      response.host_trust_id,
+      "repository SSH connection probe response.host_trust_id",
+    ),
+    expected_host_trust_revision: response.expected_host_trust_revision === null
+      ? null
+      : integer(
+        response.expected_host_trust_revision,
+        "repository SSH connection probe response.expected_host_trust_revision",
+      ),
+    candidates: array(
+      response.candidates,
+      "repository SSH connection probe response.candidates",
+    ).map(
+      (candidate, index) =>
+        repositorySshHostKeyCandidate(
+          candidate,
+          `repository SSH connection probe response.candidates[${index}]`,
+        ),
+    ),
+  };
+}
+
 const WORKSPACE_DELETION_MAX_OPERATION_ID_BYTES = 128;
 const WORKSPACE_DELETION_MAX_REVISION_BYTES = 128;
 const WORKSPACE_DELETION_MAX_BLOCKERS = 1024;

web/workspace/src/lib/workspace/repositories/ssh-connection.ts

@@ -0,0 +1,13 @@
+import type { WorkspaceRuntimeResource } from "$lib/generated/workspace-api";
+
+export function repositorySshProbeRuntimes(
+  runtimes: readonly WorkspaceRuntimeResource[],
+): WorkspaceRuntimeResource[] {
+  return runtimes.filter((runtime) =>
+    runtime.kind === "remote_worker_runtime" &&
+    runtime.management.endpoint_configured &&
+    runtime.management.binding !== undefined &&
+    runtime.management.binding !== null &&
+    runtime.management.binding.state !== "revoked"
+  );
+}

web/workspace/src/routes/w/[workspaceId]/repositories/[repositoryKey]/+page.svelte

@@ -1,8 +1,88 @@
 <script lang="ts">
-  import { formatDate } from '$lib/workspace/api/http';
+  import type {
+    ConfirmRepositorySshHostTrustRequest,
+    RepositorySshConnectionProbeRequest,
+    RepositorySshConnectionProbeResponse
+  } from '$lib/generated/workspace-api';
+  import { parseRepositorySshHostTrust } from '$lib/workspace/api/repository-access';
+  import { formatDate, workspaceApiPath } from '$lib/workspace/api/http';
+  import { parseRepositorySshConnectionProbeResponse } from '$lib/workspace/api/workspace-model';
+  import { repositorySshProbeRuntimes } from '$lib/workspace/repositories/ssh-connection';
   import type { PageProps } from './$types';
 
   let { data }: PageProps = $props();
+  let selectedRuntimeId = $state('');
+  let probe = $state<RepositorySshConnectionProbeResponse | null>(null);
+  let selectedHostKey = $state('');
+  let pending = $state(false);
+  let connectionMessage = $state<string | null>(null);
+  const probeRuntimes = $derived(data.runtimes ? repositorySshProbeRuntimes(data.runtimes.items) : []);
+
+  $effect(() => {
+    if (!selectedRuntimeId) {
+      selectedRuntimeId = probeRuntimes[0]?.runtime_id ?? '';
+    }
+  });
+
+  async function requestConnectionTest(method: 'POST' | 'PUT', body: unknown): Promise<unknown> {
+    const response = await fetch(
+      workspaceApiPath(
+        data.repository?.workspace_id ?? '',
+        `/repositories/${encodeURIComponent(data.repositoryKey)}/ssh-connection-test`
+      ),
+      {
+        method,
+        headers: { accept: 'application/json', 'content-type': 'application/json' },
+        body: JSON.stringify(body)
+      }
+    );
+    const value = await response.json();
+    if (!response.ok) {
+      const record = value && typeof value === 'object' ? value as Record<string, unknown> : null;
+      throw new Error(typeof record?.message === 'string' ? record.message : `SSH connection test failed with status ${response.status}`);
+    }
+    return value;
+  }
+
+  async function runConnectionTest() {
+    pending = true;
+    connectionMessage = null;
+    probe = null;
+    selectedHostKey = '';
+    try {
+      const body: RepositorySshConnectionProbeRequest = { runtime_id: selectedRuntimeId };
+      probe = parseRepositorySshConnectionProbeResponse(await requestConnectionTest('POST', body));
+      selectedHostKey = probe.candidates[0]?.host_key ?? '';
+      connectionMessage = probe.trust_state === 'verified'
+        ? 'The observed SSH host key matches the Workspace trust record.'
+        : 'Review the observed fingerprint before trusting this SSH host.';
+    } catch (error) {
+      connectionMessage = error instanceof Error ? error.message : 'SSH connection test failed';
+    } finally {
+      pending = false;
+    }
+  }
+
+  async function confirmHostTrust() {
+    if (!probe || !selectedHostKey) return;
+    pending = true;
+    connectionMessage = null;
+    try {
+      const body: ConfirmRepositorySshHostTrustRequest = {
+        operation_id: `repository-ssh-confirm-${crypto.randomUUID()}`,
+        runtime_id: probe.runtime_id,
+        host_key: selectedHostKey,
+        expected_host_trust_revision: probe.expected_host_trust_revision
+      };
+      parseRepositorySshHostTrust(await requestConnectionTest('PUT', body));
+      probe = { ...probe, trust_state: 'verified' };
+      connectionMessage = 'SSH host trust saved. Future connections must present this key.';
+    } catch (error) {
+      connectionMessage = error instanceof Error ? error.message : 'Failed to save SSH host trust';
+    } finally {
+      pending = false;
+    }
+  }
 </script>
 
 <svelte:head>
@@ -78,6 +158,47 @@
   {/if}
 </section>
 
+{#if data.repository?.item.source.kind === 'ssh'}
+  <section class="card repository-detail-card">
+    <h2>SSH connection test</h2>
+    <p>Observe the SSH host key from the same Runtime that will clone this Repository. Nothing is trusted until you confirm a fingerprint below.</p>
+    {#if data.runtimesError}
+      <p class="section-state error">{data.runtimesError}</p>
+    {:else if data.runtimes}
+      <label>
+        <span>Runtime</span>
+        <select bind:value={selectedRuntimeId} disabled={pending}>
+          {#each probeRuntimes as runtime}
+            <option value={runtime.runtime_id}>{runtime.label} · {runtime.runtime_id}</option>
+          {/each}
+        </select>
+      </label>
+      {#if probeRuntimes.length === 0}
+        <p class="section-state error">No configured remote Runtime is available for this connection test.</p>
+      {/if}
+      <button type="button" disabled={pending || !selectedRuntimeId} onclick={() => void runConnectionTest()}>
+        {pending ? 'Checking…' : 'Check SSH connection'}
+      </button>
+    {/if}
+
+    {#if probe}
+      <p><strong>{probe.hostname}:{probe.port}</strong> · {probe.trust_state}</p>
+      {#each probe.candidates as candidate}
+        <label class="repository-host-key-candidate">
+          <input type="radio" name="repository-host-key" bind:group={selectedHostKey} value={candidate.host_key} />
+          <span><code>{candidate.algorithm}</code> <code>{candidate.fingerprint}</code></span>
+        </label>
+      {/each}
+      {#if probe.trust_state !== 'verified'}
+        <button type="button" class="danger" disabled={pending || !selectedHostKey} onclick={() => void confirmHostTrust()}>
+          Confirm and trust selected host key
+        </button>
+      {/if}
+    {/if}
+    {#if connectionMessage}<p class="section-state" class:error={probe === null}>{connectionMessage}</p>{/if}
+  </section>
+{/if}
+
 <section class="card repository-log-card">
   <h2>Recent commits</h2>
   {#if data.repositoryLog}

web/workspace/src/routes/w/[workspaceId]/repositories/[repositoryKey]/+page.ts

@@ -1,4 +1,5 @@
 import { loadJson, workspaceApiPath } from "$lib/workspace/api/http";
+import { parseWorkspaceRuntimeList } from "$lib/workspace/api/runtime-management";
 import {
   parseRepositoryDetailResponse,
   parseRepositoryLogResponse,
@@ -8,7 +9,7 @@ import type { PageLoad } from "./$types";
 export const load: PageLoad = async ({ fetch, params }) => {
   const workspaceId = params.workspaceId;
   const repositoryKey = params.repositoryKey;
-  const [repositoryResult, logResult] = await Promise.all([
+  const [repositoryResult, logResult, runtimesResult] = await Promise.all([
     loadJson<unknown>(
       fetch,
       workspaceApiPath(
@@ -23,6 +24,10 @@ export const load: PageLoad = async ({ fetch, params }) => {
         `/repositories/${encodeURIComponent(repositoryKey)}/log`,
       ),
     ),
+    loadJson<unknown>(
+      fetch,
+      workspaceApiPath(workspaceId, "/runtimes"),
+    ),
   ]);
 
   let repository = null;
@@ -49,11 +54,25 @@ export const load: PageLoad = async ({ fetch, params }) => {
     }
   }
 
+  let runtimes = null;
+  let runtimesError = runtimesResult.error;
+  if (runtimesResult.data !== null) {
+    try {
+      runtimes = parseWorkspaceRuntimeList(runtimesResult.data);
+    } catch (cause) {
+      runtimesError = cause instanceof Error
+        ? cause.message
+        : "invalid Runtime summary response";
+    }
+  }
+
   return {
     repositoryKey,
     repository,
     repositoryError,
     repositoryLog: log,
     repositoryLogError: logError,
+    runtimes,
+    runtimesError,
   };
 };

web/workspace/src/routes/w/[workspaceId]/settings/repository-access/+page.svelte

@@ -4,24 +4,33 @@
     CreateRepositorySshCredentialRequest,
     DeleteRepositorySshCredentialRequest,
     DeleteRepositorySshHostTrustRequest,
+    GenerateRepositorySshCredentialRequest,
     PutRepositorySshHostTrustRequest,
     RepositorySshCredential,
     RepositorySshHostTrust,
+    RepositorySshPublicKey,
     RotateRepositorySshCredentialRequest,
   } from '$lib/generated/repository-access-api';
   import {
     parseRepositorySshCredential,
     parseRepositorySshHostTrust,
+    parseRepositorySshPublicKey,
   } from '$lib/workspace/api/repository-access';
   import type { PageProps } from './$types';
 
   let { data }: PageProps = $props();
   let credentials = $state<RepositorySshCredential[]>(untrack(() => data.credentials));
+  let publicKeys = $state<Record<string, RepositorySshPublicKey>>(
+    Object.fromEntries(untrack(() => data.publicKeys).map((key) => [key.credential_id, key]))
+  );
   let hostTrusts = $state<RepositorySshHostTrust[]>(untrack(() => data.hostTrusts));
   const accessProjection = untrack(() => data.accessProjection);
   let message = $state<string | null>(null);
   let pending = $state(false);
+  let copiedCredentialId = $state<string | null>(null);
 
+  let generateCredentialId = $state('');
+  let generateCredentialName = $state('');
   let credentialId = $state('');
   let credentialName = $state('');
   let privateKey = $state('');
@@ -37,6 +46,7 @@
   let hostExpectedRevision = $state<number | null>(null);
 
   const base = $derived(`/api/w/${encodeURIComponent(data.workspaceId)}/settings/repository-access`);
+  const workspaceDefaultCredentialId = 'workspace-default';
 
   function operationId(prefix: string): string {
     return `${prefix}-${crypto.randomUUID()}`;
@@ -71,6 +81,55 @@
     return parse(payload);
   }
 
+  async function loadPublicKey(credentialId: string): Promise<RepositorySshPublicKey> {
+    const response = await fetch(
+      `${base}/credentials/${encodeURIComponent(credentialId)}/public-key`,
+      { headers: { accept: 'application/json' } }
+    );
+    const body = await response.json();
+    if (!response.ok) {
+      throw new Error(`Repository Access request failed with status ${response.status}.`);
+    }
+    return parseRepositorySshPublicKey(body);
+  }
+
+  async function generateCredential() {
+    pending = true;
+    message = null;
+    try {
+      const body: GenerateRepositorySshCredentialRequest = {
+        operation_id: operationId('credential-generate'),
+        credential_id: generateCredentialId,
+        name: generateCredentialName
+      };
+      const created = await request('/credentials/generate', 'POST', body, parseRepositorySshCredential);
+      const publicKey = await loadPublicKey(created.credential_id);
+      credentials = [...credentials.filter((item) => item.credential_id !== created.credential_id), created];
+      publicKeys = { ...publicKeys, [created.credential_id]: publicKey };
+      generateCredentialId = '';
+      generateCredentialName = '';
+      message = `Generated SSH credential ${created.credential_id}`;
+    } catch (error) {
+      message = error instanceof Error ? error.message : 'Failed to generate SSH credential';
+    } finally {
+      pending = false;
+    }
+  }
+
+  async function copyPublicKey(credentialId: string) {
+    const publicKey = publicKeys[credentialId]?.public_key;
+    if (!publicKey) return;
+    try {
+      await navigator.clipboard.writeText(publicKey);
+      copiedCredentialId = credentialId;
+      window.setTimeout(() => {
+        if (copiedCredentialId === credentialId) copiedCredentialId = null;
+      }, 1500);
+    } catch {
+      message = 'Failed to copy the public key';
+    }
+  }
+
   async function createCredential() {
     pending = true;
     message = null;
@@ -88,7 +147,9 @@
         body,
         parseRepositorySshCredential
       );
+      const publicKey = await loadPublicKey(created.credential_id);
       credentials = [...credentials, created].sort((a, b) => a.credential_id.localeCompare(b.credential_id));
+      publicKeys = { ...publicKeys, [created.credential_id]: publicKey };
       credentialId = '';
       credentialName = '';
       message = `Credential ${created.credential_id} created. Pasted secret fields were cleared.`;
@@ -117,7 +178,9 @@
         body,
         parseRepositorySshCredential
       );
+      const publicKey = await loadPublicKey(rotated.credential_id);
       credentials = credentials.map((entry) => entry.credential_id === rotated.credential_id ? rotated : entry);
+      publicKeys = { ...publicKeys, [rotated.credential_id]: publicKey };
       rotateCredentialId = null;
       message = `Credential ${rotated.credential_id} rotated to revision ${rotated.current_revision}. Pasted secret fields were cleared.`;
     } catch (error) {
@@ -145,6 +208,9 @@
         null
       );
       credentials = credentials.filter((entry) => entry.credential_id !== credential.credential_id);
+      const remainingPublicKeys = { ...publicKeys };
+      delete remainingPublicKeys[credential.credential_id];
+      publicKeys = remainingPublicKeys;
       message = `Credential ${credential.credential_id} deleted.`;
     } catch (error) {
       message = error instanceof Error ? error.message : 'Credential deletion failed';
@@ -227,7 +293,7 @@
     <div><p class="eyebrow">owner only</p><h2>Repository Access</h2></div>
     <span class="badge success">encrypted</span>
   </header>
-  <p>Manage Workspace-scoped SSH credentials and pinned host keys. Private keys and passphrases are write-only and never returned by this page.</p>
+  <p>The Workspace default SSH key is generated separately from the Runtime authentication identity and is always offered during SSH clone. Without an explicit Repository binding, a unique pinned host trust matching the Repository URI is used with this default key. A binding can add one dedicated credential; OpenSSH receives both candidates and tries them through one operation-scoped agent. Private keys and passphrases remain write-only.</p>
   {#if message}<p class="status-message">{message}</p>{/if}
 
   <div class="settings-runtime-list">
@@ -237,7 +303,7 @@
     {#each accessProjection.bindings as binding (binding.repository_key)}
       <div class="card">
         <strong>{binding.repository_key}</strong>
-        <p>{binding.access} · credential <code>{binding.credential_id}</code> · host trust <code>{binding.host_trust_id}</code></p>
+        <p>{binding.access} · additional credential <code>{binding.credential_id}</code> · always includes <code>{workspaceDefaultCredentialId}</code> · host trust <code>{binding.host_trust_id}</code></p>
       </div>
     {/each}
   </div>
@@ -248,12 +314,19 @@
     {#each credentials as credential (credential.credential_id)}
       <div class="card">
         <strong>{credential.name}</strong> <code>{credential.credential_id}</code>
+        {#if credential.credential_id === workspaceDefaultCredentialId}<span class="badge success">Workspace default</span>{/if}
         <p>{credential.public_key_algorithm} · {credential.public_key_fingerprint} · revision {credential.current_revision}</p>
-        <p>References: {credential.referenced_repositories.join(', ') || 'none'}</p>
+        {#if publicKeys[credential.credential_id]}
+          <label><span>Public key</span><textarea readonly rows="3" value={publicKeys[credential.credential_id].public_key}></textarea></label>
+          <button type="button" onclick={() => void copyPublicKey(credential.credential_id)}>{copiedCredentialId === credential.credential_id ? 'Copied' : 'Copy public key'}</button>
+        {/if}
+        <p>References: {credential.credential_id === workspaceDefaultCredentialId ? 'all SSH repository operations' : credential.referenced_repositories.join(', ') || 'none'}</p>
+        {#if credential.credential_id !== workspaceDefaultCredentialId}
           <div class="settings-action-row">
             <button type="button" onclick={() => (rotateCredentialId = rotateCredentialId === credential.credential_id ? null : credential.credential_id)}>Rotate</button>
             <button type="button" class="danger" disabled={pending || credential.referenced_repositories.length > 0} onclick={() => void deleteCredential(credential)}>Delete</button>
           </div>
+        {/if}
         {#if rotateCredentialId === credential.credential_id}
           <form class="settings-runtime-form" onsubmit={(event) => { event.preventDefault(); void rotateCredential(credential); }}>
             <label><span>New private key</span><textarea bind:value={rotatePrivateKey} required rows="8" autocomplete="off"></textarea></label>
@@ -264,8 +337,16 @@
       </div>
     {/each}
 
+    <form class="settings-runtime-form" onsubmit={(event) => { event.preventDefault(); void generateCredential(); }}>
+      <h3>Generate Repository SSH credential</h3>
+      <p>Create an additional Ed25519 key for a Repository binding. The Workspace default SSH key is already generated automatically and is included separately.</p>
+      <label><span>Credential id</span><input bind:value={generateCredentialId} placeholder="repository-deploy" required pattern="[A-Za-z0-9_.-]+" maxlength="128" /></label>
+      <label><span>Name</span><input bind:value={generateCredentialName} placeholder="Repository deploy key" required maxlength="200" /></label>
+      <button type="submit" disabled={pending}>Generate credential</button>
+    </form>
+
     <form class="settings-runtime-form" onsubmit={(event) => { event.preventDefault(); void createCredential(); }}>
-      <h3>Add SSH credential</h3>
+      <h3>Import existing SSH credential</h3>
       <label><span>Credential id</span><input bind:value={credentialId} required pattern="[A-Za-z0-9_.-]+" maxlength="128" /></label>
       <label><span>Name</span><input bind:value={credentialName} required maxlength="200" /></label>
       <label><span>OpenSSH private key (ssh-ed25519)</span><textarea bind:value={privateKey} required rows="10" autocomplete="off"></textarea></label>

web/workspace/src/routes/w/[workspaceId]/settings/repository-access/+page.ts

@@ -3,6 +3,7 @@ import {
   parseRepositoryAccessProjection,
   parseRepositorySshCredentials,
   parseRepositorySshHostTrusts,
+  parseRepositorySshPublicKey,
 } from "$lib/workspace/api/repository-access";
 import { loadRepositoryAccessJson } from "$lib/workspace/api/repository-access-loader";
 import type { PageLoad } from "./$types";
@@ -27,9 +28,25 @@ export const load: PageLoad = async ({ fetch, params }) => {
     ),
   ]);
 
+  const publicKeys = await Promise.all(
+    credentials.map((credential) =>
+      loadRepositoryAccessJson(
+        fetch,
+        workspaceApiPath(
+          workspaceId,
+          `/settings/repository-access/credentials/${
+            encodeURIComponent(credential.credential_id)
+          }/public-key`,
+        ),
+        parseRepositorySshPublicKey,
+      )
+    ),
+  );
+
   return {
     workspaceId,
     credentials,
+    publicKeys,
     hostTrusts,
     accessProjection,
   };

web/workspace/test/repository-access/api.test.ts

@@ -2,6 +2,7 @@ import {
   parseRepositoryAccessProjection,
   parseRepositorySshCredentials,
   parseRepositorySshHostTrusts,
+  parseRepositorySshPublicKey,
   RepositoryAccessSchemaError,
 } from "../../src/lib/workspace/api/repository-access.ts";
 
@@ -59,6 +60,22 @@ const hostTrust = {
 
 Deno.test("Repository Access parsers accept generated response contracts", () => {
   assertEquals(parseRepositorySshCredentials([credential]), [credential]);
+  assertEquals(
+    parseRepositorySshPublicKey({
+      credential_id: "deploy-key",
+      current_revision: 2,
+      public_key_algorithm: "ssh-ed25519",
+      public_key_fingerprint: "SHA256:credential",
+      public_key: "ssh-ed25519 AAAA",
+    }),
+    {
+      credential_id: "deploy-key",
+      current_revision: 2,
+      public_key_algorithm: "ssh-ed25519",
+      public_key_fingerprint: "SHA256:credential",
+      public_key: "ssh-ed25519 AAAA",
+    },
+  );
   assertEquals(parseRepositorySshHostTrusts([hostTrust]), [hostTrust]);
   assertEquals(
     parseRepositoryAccessProjection({

web/workspace/test/repository-access/ui.test.ts

@@ -28,6 +28,7 @@ test("Repository Access Web code consumes workspace-api generated DTOs", () => {
   assert(
     loaderSource.includes("parseRepositorySshCredentials") &&
       loaderSource.includes("parseRepositorySshHostTrusts") &&
+      loaderSource.includes("parseRepositorySshPublicKey") &&
       loaderSource.includes("parseRepositoryAccessProjection"),
     "loader should validate unknown JSON before exposing generated DTOs to Svelte",
   );
@@ -66,6 +67,29 @@ test("Repository Access renders the shared access projection fields", () => {
   }
 });
 
+test("Repository Access generates and copies selectable public keys", () => {
+  for (
+    const token of [
+      "/credentials/generate",
+      "/public-key",
+      "Generate Repository SSH credential",
+      "navigator.clipboard.writeText",
+      "publicKeys[credential.credential_id]",
+      "workspace-default",
+      "always offered during SSH clone",
+    ]
+  ) {
+    assert(
+      source.includes(token),
+      `missing generated public key flow ${token}`,
+    );
+  }
+  assert(
+    source.includes("binding.credential_id"),
+    "Repository bindings should identify the selected credential",
+  );
+});
+
 test("Repository credential submissions clear write-only fields in finally blocks", () => {
   const createStart = source.indexOf("async function createCredential()");
   const rotateStart = source.indexOf("async function rotateCredential(");

web/workspace/test/repository-ssh-connection-ui.test.ts

@@ -0,0 +1,106 @@
+import { assert, assertEquals } from "jsr:@std/assert";
+import type { WorkspaceRuntimeResource } from "../src/lib/generated/workspace-api.ts";
+import { parseRepositorySshConnectionProbeResponse } from "../src/lib/workspace/api/workspace-model.ts";
+import { repositorySshProbeRuntimes } from "../src/lib/workspace/repositories/ssh-connection.ts";
+
+const root = new URL("../", import.meta.url);
+const pageSource = await Deno.readTextFile(
+  new URL(
+    "./src/routes/w/[workspaceId]/repositories/[repositoryKey]/+page.svelte",
+    root,
+  ),
+);
+const loaderSource = await Deno.readTextFile(
+  new URL(
+    "./src/routes/w/[workspaceId]/repositories/[repositoryKey]/+page.ts",
+    root,
+  ),
+);
+
+Deno.test("Repository SSH probe parser preserves the confirmation contract", () => {
+  const response = {
+    workspace_id: "workspace-a",
+    repository_key: "main",
+    runtime_id: "runtime-a",
+    hostname: "example.test",
+    port: 22,
+    trust_state: "untrusted" as const,
+    host_trust_id: "tofu-example.test-22",
+    expected_host_trust_revision: null,
+    candidates: [
+      {
+        algorithm: "ssh-ed25519",
+        host_key: "ssh-ed25519 AAAA",
+        fingerprint: "SHA256:host",
+      },
+    ],
+  };
+
+  assertEquals(parseRepositorySshConnectionProbeResponse(response), response);
+});
+
+Deno.test("Repository SSH probe offers configured remote Runtimes regardless of worker-style status", () => {
+  const configured = {
+    runtime_id: "arcadia",
+    label: "Arcadia",
+    kind: "remote_worker_runtime",
+    status: "idle",
+    diagnostics: [],
+    management: {
+      endpoint_configured: true,
+      endpoint_display: "https://arcadia.example",
+      binding: {
+        state: "verified",
+      },
+    },
+  } as unknown as WorkspaceRuntimeResource;
+  const embedded = {
+    ...configured,
+    runtime_id: "embedded-worker-runtime",
+    kind: "embedded_worker_runtime",
+  } as unknown as WorkspaceRuntimeResource;
+  const revoked = {
+    ...configured,
+    runtime_id: "revoked",
+    management: {
+      ...configured.management,
+      binding: { state: "revoked" },
+    },
+  } as unknown as WorkspaceRuntimeResource;
+  const unbound = {
+    ...configured,
+    runtime_id: "unbound",
+    management: {
+      ...configured.management,
+      binding: undefined,
+    },
+  } as unknown as WorkspaceRuntimeResource;
+
+  assertEquals(
+    repositorySshProbeRuntimes([embedded, configured, revoked, unbound]).map((
+      runtime,
+    ) => runtime.runtime_id),
+    ["arcadia"],
+  );
+});
+
+Deno.test("Repository SSH connection test requires an explicit host-key confirmation", () => {
+  for (
+    const token of [
+      "Check SSH connection",
+      "selectedRuntimeId",
+      "candidate.fingerprint",
+      "Confirm and trust selected host key",
+      "expected_host_trust_revision",
+      "requestConnectionTest('POST'",
+      "requestConnectionTest('PUT'",
+    ]
+  ) {
+    assert(pageSource.includes(token), `missing SSH connection flow ${token}`);
+  }
+});
+
+Deno.test("Repository detail loads configured Workspace Runtimes for the connection test", () => {
+  assert(loaderSource.includes('workspaceApiPath(workspaceId, "/runtimes")'));
+  assert(loaderSource.includes("parseWorkspaceRuntimeList"));
+});