feat: add browser execution workspaces

crates/worker-runtime/src/catalog.rs

@@ -89,6 +89,13 @@ pub struct ExecutionWorkspaceRequest {
     pub dirty_state_policy: DirtyStatePolicy,
 }
 
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
+pub struct ExecutionWorkspaceAllocationClaim {
+    pub allocation_id: String,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub relative_cwd: Option<String>,
+}
+
 #[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
 #[serde(rename_all = "snake_case")]
 pub enum ExecutionWorkspaceStatusKind {
@@ -108,6 +115,8 @@ pub struct ExecutionWorkspaceCleanupTarget {
 pub struct ExecutionWorkspaceSummary {
     pub allocation_id: String,
     pub repository_id: String,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub requested_selector: Option<String>,
     pub materializer_kind: MaterializerKind,
     pub dirty_state_policy: DirtyStatePolicy,
     #[serde(default, skip_serializing_if = "Option::is_none")]
@@ -144,6 +153,8 @@ pub struct CreateWorkerRequest {
     pub initial_input: Option<WorkerInput>,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub execution_workspace: Option<ExecutionWorkspaceRequest>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub execution_workspace_allocation: Option<ExecutionWorkspaceAllocationClaim>,
 }
 
 /// Worker lifecycle status for the in-memory embedded runtime.

crates/worker-runtime/src/execution_workspace.rs

@@ -6,16 +6,20 @@ use crate::catalog::{
 use crate::identity::WorkerRef;
 use serde::{Deserialize, Serialize};
 use std::fs;
-use std::path::{Path, PathBuf};
+use std::path::{Component, Path, PathBuf};
 use std::process::Command;
+use std::sync::atomic::{AtomicU64, Ordering};
 use std::time::{SystemTime, UNIX_EPOCH};
 
 const EXECUTION_WORKSPACES_DIR: &str = "execution-workspaces";
 const MATERIALIZATION_RECORD: &str = "materialization.json";
+static NEXT_ALLOCATION_SEQUENCE: AtomicU64 = AtomicU64::new(0);
 
 #[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
 pub struct ExecutionWorkspaceEvidence {
     pub repository_id: String,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub requested_selector: Option<String>,
     pub resolved_commit: String,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub resolved_tree: Option<String>,
@@ -40,6 +44,7 @@ impl ExecutionWorkspaceAllocation {
         ExecutionWorkspaceSummary {
             allocation_id: self.id.clone(),
             repository_id: self.repository_id.clone(),
+            requested_selector: self.evidence.requested_selector.clone(),
             materializer_kind: self.materializer_kind.clone(),
             dirty_state_policy: self.dirty_state_policy.clone(),
             resolved_commit: Some(self.evidence.resolved_commit.clone()),
@@ -114,6 +119,31 @@ pub trait ExecutionWorkspaceMaterializer: Send + Sync + 'static {
         request: &ExecutionWorkspaceRequest,
     ) -> Result<ExecutionWorkspaceBinding, ExecutionWorkspaceDiagnostic>;
 
+    fn preallocate(
+        &self,
+        request: &ExecutionWorkspaceRequest,
+    ) -> Result<ExecutionWorkspaceBinding, ExecutionWorkspaceDiagnostic>;
+
+    fn bind_allocation(
+        &self,
+        allocation_id: &str,
+        relative_cwd: Option<&str>,
+    ) -> Result<ExecutionWorkspaceBinding, ExecutionWorkspaceDiagnostic>;
+
+    fn list_allocations(
+        &self,
+    ) -> Result<Vec<ExecutionWorkspaceStatus>, ExecutionWorkspaceDiagnostic>;
+
+    fn allocation_status(
+        &self,
+        allocation_id: &str,
+    ) -> Result<ExecutionWorkspaceStatus, ExecutionWorkspaceDiagnostic>;
+
+    fn cleanup_allocation(
+        &self,
+        allocation_id: &str,
+    ) -> Result<ExecutionWorkspaceStatus, ExecutionWorkspaceDiagnostic>;
+
     fn cleanup(
         &self,
         binding: &ExecutionWorkspaceBinding,
@@ -174,14 +204,41 @@ impl LocalGitWorktreeMaterializer {
             )
         })
     }
+
+    fn read_binding(
+        &self,
+        allocation_id: &str,
+    ) -> Result<ExecutionWorkspaceBinding, ExecutionWorkspaceDiagnostic> {
+        let allocation_root = self.allocation_root(allocation_id);
+        let path = allocation_root.join(MATERIALIZATION_RECORD);
+        let raw = fs::read(&path).map_err(|_| {
+            ExecutionWorkspaceDiagnostic::new(
+                "execution_workspace_allocation_not_found",
+                "execution workspace allocation was not found",
+            )
+        })?;
+        let record: ExecutionWorkspaceMaterializationRecord = serde_json::from_slice(&raw).map_err(|_| {
+            ExecutionWorkspaceDiagnostic::new(
+                "execution_workspace_record_invalid",
+                "execution workspace allocation record is invalid; backend-private path details were omitted",
+            )
+        })?;
+        Ok(ExecutionWorkspaceBinding {
+            allocation: record.allocation,
+            workspace_root: record.workspace_root.clone(),
+            cwd: record.workspace_root,
+            allocation_root,
+            source_repository_path: record.source_repository_path,
+        })
     }
 
-impl ExecutionWorkspaceMaterializer for LocalGitWorktreeMaterializer {
+    fn materialize_with_allocation_id(
-    fn materialize(
         &self,
-        worker_ref: &WorkerRef,
+        allocation_id: String,
         request: &ExecutionWorkspaceRequest,
+        cleanup_policy: &str,
     ) -> Result<ExecutionWorkspaceBinding, ExecutionWorkspaceDiagnostic> {
+        validate_allocation_id(&allocation_id)?;
         if request.materializer != MaterializerKind::LocalGitWorktree {
             return Err(ExecutionWorkspaceDiagnostic::new(
                 "execution_workspace_materializer_unsupported",
@@ -248,7 +305,6 @@ impl ExecutionWorkspaceMaterializer for LocalGitWorktreeMaterializer {
             .map(|value| value.trim().to_string())
             .filter(|value| !value.is_empty());
 
-        let allocation_id = Self::allocation_id(worker_ref, &request.repository.id);
         let allocation_root = self.allocation_root(&allocation_id);
         let workspace_root = allocation_root
             .join("root")
@@ -256,7 +312,7 @@ impl ExecutionWorkspaceMaterializer for LocalGitWorktreeMaterializer {
         if workspace_root.exists() {
             return Err(ExecutionWorkspaceDiagnostic::new(
                 "execution_workspace_allocation_exists",
-                "execution workspace allocation target already exists; cleanup or choose a new Worker allocation",
+                "execution workspace allocation target already exists; cleanup or choose a new allocation",
             ));
         }
         fs::create_dir_all(workspace_root.parent().ok_or_else(|| {
@@ -285,12 +341,17 @@ impl ExecutionWorkspaceMaterializer for LocalGitWorktreeMaterializer {
         )?;
 
         let allocation = ExecutionWorkspaceAllocation {
-            id: allocation_id,
+            id: allocation_id.clone(),
             repository_id: request.repository.id.clone(),
             materializer_kind: MaterializerKind::LocalGitWorktree,
             dirty_state_policy: DirtyStatePolicy::CleanPointOnly,
             evidence: ExecutionWorkspaceEvidence {
                 repository_id: request.repository.id.clone(),
+                requested_selector: request
+                    .repository
+                    .selector
+                    .as_ref()
+                    .map(|selector| selector.as_ref().to_string()),
                 resolved_commit,
                 resolved_tree,
                 materializer_kind: MaterializerKind::LocalGitWorktree,
@@ -298,10 +359,10 @@ impl ExecutionWorkspaceMaterializer for LocalGitWorktreeMaterializer {
             },
             cleanup_target: ExecutionWorkspaceCleanupTarget {
                 kind: "git_worktree".to_string(),
-                allocation_id: Self::allocation_id(worker_ref, &request.repository.id),
+                allocation_id,
                 repository_id: request.repository.id.clone(),
             },
-            cleanup_policy: "remove_on_worker_stop".to_string(),
+            cleanup_policy: cleanup_policy.to_string(),
             status: ExecutionWorkspaceStatusKind::Active,
         };
         let binding = ExecutionWorkspaceBinding {
@@ -314,20 +375,128 @@ impl ExecutionWorkspaceMaterializer for LocalGitWorktreeMaterializer {
         self.write_record(&binding)?;
         Ok(binding)
     }
+}
+
+impl ExecutionWorkspaceMaterializer for LocalGitWorktreeMaterializer {
+    fn materialize(
+        &self,
+        worker_ref: &WorkerRef,
+        request: &ExecutionWorkspaceRequest,
+    ) -> Result<ExecutionWorkspaceBinding, ExecutionWorkspaceDiagnostic> {
+        let allocation_id = Self::allocation_id(worker_ref, &request.repository.id);
+        self.materialize_with_allocation_id(allocation_id, request, "remove_on_worker_stop")
+    }
+
+    fn preallocate(
+        &self,
+        request: &ExecutionWorkspaceRequest,
+    ) -> Result<ExecutionWorkspaceBinding, ExecutionWorkspaceDiagnostic> {
+        let allocation_id = next_allocation_id(&request.repository.id);
+        self.materialize_with_allocation_id(allocation_id, request, "manual_or_worker_stop")
+    }
+
+    fn bind_allocation(
+        &self,
+        allocation_id: &str,
+        relative_cwd: Option<&str>,
+    ) -> Result<ExecutionWorkspaceBinding, ExecutionWorkspaceDiagnostic> {
+        validate_allocation_id(allocation_id)?;
+        let binding = self.read_binding(allocation_id)?;
+        if binding.allocation.status != ExecutionWorkspaceStatusKind::Active {
+            return Err(ExecutionWorkspaceDiagnostic::new(
+                "execution_workspace_not_active",
+                "execution workspace allocation is not active",
+            ));
+        }
+        let cwd = validate_relative_cwd(binding.workspace_root(), relative_cwd)?;
+        Ok(ExecutionWorkspaceBinding { cwd, ..binding })
+    }
+
+    fn list_allocations(
+        &self,
+    ) -> Result<Vec<ExecutionWorkspaceStatus>, ExecutionWorkspaceDiagnostic> {
+        let root = self.runtime_root.join(EXECUTION_WORKSPACES_DIR);
+        let entries = match fs::read_dir(&root) {
+            Ok(entries) => entries,
+            Err(error) if error.kind() == std::io::ErrorKind::NotFound => return Ok(Vec::new()),
+            Err(_) => {
+                return Err(ExecutionWorkspaceDiagnostic::new(
+                    "execution_workspace_list_failed",
+                    "failed to list execution workspace allocations; backend-private path details were omitted",
+                ));
+            }
+        };
+        let mut statuses = Vec::new();
+        for entry in entries.flatten() {
+            let file_type = match entry.file_type() {
+                Ok(file_type) => file_type,
+                Err(_) => continue,
+            };
+            if !file_type.is_dir() {
+                continue;
+            }
+            let allocation_id = entry.file_name().to_string_lossy().to_string();
+            if validate_allocation_id(&allocation_id).is_err() {
+                continue;
+            }
+            if let Ok(status) = self.allocation_status(&allocation_id) {
+                statuses.push(status);
+            }
+        }
+        statuses
+            .sort_by(|left, right| left.summary.allocation_id.cmp(&right.summary.allocation_id));
+        Ok(statuses)
+    }
+
+    fn allocation_status(
+        &self,
+        allocation_id: &str,
+    ) -> Result<ExecutionWorkspaceStatus, ExecutionWorkspaceDiagnostic> {
+        validate_allocation_id(allocation_id)?;
+        Ok(self.read_binding(allocation_id)?.status())
+    }
+
+    fn cleanup_allocation(
+        &self,
+        allocation_id: &str,
+    ) -> Result<ExecutionWorkspaceStatus, ExecutionWorkspaceDiagnostic> {
+        validate_allocation_id(allocation_id)?;
+        let binding = self.read_binding(allocation_id)?;
+        self.cleanup(&binding)?;
+        self.allocation_status(allocation_id)
+    }
 
     fn cleanup(
         &self,
         binding: &ExecutionWorkspaceBinding,
     ) -> Result<(), ExecutionWorkspaceDiagnostic> {
         let mut allocation = binding.allocation.clone();
-        let workspace_root_arg = path_str(binding.workspace_root())?;
+        let allocation_root = binding.allocation_root.canonicalize().map_err(|_| {
+            ExecutionWorkspaceDiagnostic::new(
+                "execution_workspace_cleanup_target_invalid",
+                "execution workspace allocation root is unavailable; backend-private path details were omitted",
+            )
+        })?;
+        let workspace_root = binding.workspace_root.canonicalize().map_err(|_| {
+            ExecutionWorkspaceDiagnostic::new(
+                "execution_workspace_cleanup_target_invalid",
+                "execution workspace root is unavailable; backend-private path details were omitted",
+            )
+        })?;
+        if !workspace_root.starts_with(&allocation_root) {
+            return Err(ExecutionWorkspaceDiagnostic::new(
+                "execution_workspace_cleanup_escape_rejected",
+                "execution workspace cleanup target is outside the allocation root",
+            ));
+        }
+        let workspace_root_arg = path_str(&workspace_root)?;
         let remove_result = git_status(
             binding.source_repository_path(),
             ["worktree", "remove", "--force", workspace_root_arg.as_str()],
         )
         .or_else(|_| {
-            if binding.workspace_root.exists() {
+            if workspace_root.exists() {
-                fs::remove_dir_all(binding.workspace_root()).map_err(|_| {
+                fs::remove_dir_all(&workspace_root).map_err(|_| {
                     ExecutionWorkspaceDiagnostic::new(
                         "execution_workspace_cleanup_failed",
                         "failed to remove execution workspace; backend-private path details were omitted",
@@ -431,6 +600,80 @@ fn sanitize_path_component(value: &str) -> String {
     }
 }
 
+fn next_allocation_id(repository_id: &str) -> String {
+    let now = SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .map(|duration| duration.as_millis())
+        .unwrap_or_default();
+    let sequence = NEXT_ALLOCATION_SEQUENCE.fetch_add(1, Ordering::Relaxed);
+    format!(
+        "alloc-{now}-{sequence}-{}",
+        sanitize_path_component(repository_id)
+    )
+}
+
+fn validate_allocation_id(allocation_id: &str) -> Result<(), ExecutionWorkspaceDiagnostic> {
+    let sanitized = sanitize_path_component(allocation_id);
+    if allocation_id.is_empty()
+        || allocation_id != sanitized
+        || allocation_id.contains(std::path::MAIN_SEPARATOR)
+        || allocation_id.contains('/')
+        || allocation_id.contains('\\')
+    {
+        return Err(ExecutionWorkspaceDiagnostic::new(
+            "execution_workspace_allocation_id_invalid",
+            "execution workspace allocation id is invalid",
+        ));
+    }
+    Ok(())
+}
+
+fn validate_relative_cwd(
+    workspace_root: &Path,
+    relative_cwd: Option<&str>,
+) -> Result<PathBuf, ExecutionWorkspaceDiagnostic> {
+    let workspace_root = workspace_root.canonicalize().map_err(|_| {
+        ExecutionWorkspaceDiagnostic::new(
+            "execution_workspace_root_unavailable",
+            "execution workspace root is unavailable; backend-private path details were omitted",
+        )
+    })?;
+    let relative = relative_cwd.unwrap_or(".").trim();
+    if relative.is_empty() || relative == "." {
+        return Ok(workspace_root);
+    }
+    let relative_path = Path::new(relative);
+    if relative_path.is_absolute()
+        || relative_path.components().any(|component| {
+            matches!(
+                component,
+                Component::ParentDir | Component::RootDir | Component::Prefix(_)
+            )
+        })
+    {
+        return Err(ExecutionWorkspaceDiagnostic::new(
+            "execution_workspace_relative_cwd_invalid",
+            "execution workspace relative_cwd must be a relative path inside the allocation root",
+        ));
+    }
+    let target = workspace_root
+        .join(relative_path)
+        .canonicalize()
+        .map_err(|_| {
+            ExecutionWorkspaceDiagnostic::new(
+                "execution_workspace_relative_cwd_unavailable",
+                "execution workspace relative_cwd does not identify an existing directory",
+            )
+        })?;
+    if !target.starts_with(&workspace_root) || !target.is_dir() {
+        return Err(ExecutionWorkspaceDiagnostic::new(
+            "execution_workspace_relative_cwd_escape_rejected",
+            "execution workspace relative_cwd must resolve to a directory inside the allocation root",
+        ));
+    }
+    Ok(target)
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -575,6 +818,83 @@ mod tests {
         );
     }
 
+    #[test]
+    fn preallocated_allocation_binds_safe_relative_cwd_and_lists_without_paths() {
+        let repo = create_clean_repo();
+        fs::create_dir_all(repo.path().join("crates/yoi")).unwrap();
+        fs::write(repo.path().join("crates/yoi/lib.rs"), "// ok\n").unwrap();
+        git(repo.path(), &["add", "crates/yoi/lib.rs"]);
+        git(repo.path(), &["commit", "-m", "add crate"]);
+        let runtime_root = tempfile::tempdir().unwrap();
+        let materializer = LocalGitWorktreeMaterializer::new(runtime_root.path());
+        let allocation = materializer.preallocate(&request(repo.path())).unwrap();
+
+        let bound = materializer
+            .bind_allocation(&allocation.allocation.id, Some("crates/yoi"))
+            .unwrap();
+        assert_eq!(bound.cwd.file_name().unwrap(), "yoi");
+        let listed = materializer.list_allocations().unwrap();
+        assert_eq!(listed.len(), 1);
+        assert_eq!(listed[0].summary.allocation_id, allocation.allocation.id);
+        assert_eq!(
+            listed[0].summary.requested_selector.as_deref(),
+            Some("HEAD")
+        );
+    }
+
+    #[test]
+    fn relative_cwd_rejects_absolute_parent_nonexistent_file_and_symlink_escape() {
+        let repo = create_clean_repo();
+        fs::create_dir_all(repo.path().join("inside")).unwrap();
+        fs::write(repo.path().join("inside/file.txt"), "file\n").unwrap();
+        git(repo.path(), &["add", "inside/file.txt"]);
+        git(repo.path(), &["commit", "-m", "add inside"]);
+        let runtime_root = tempfile::tempdir().unwrap();
+        let materializer = LocalGitWorktreeMaterializer::new(runtime_root.path());
+        let allocation = materializer.preallocate(&request(repo.path())).unwrap();
+
+        assert_eq!(
+            materializer
+                .bind_allocation(&allocation.allocation.id, Some("/tmp"))
+                .unwrap_err()
+                .code,
+            "execution_workspace_relative_cwd_invalid"
+        );
+        assert_eq!(
+            materializer
+                .bind_allocation(&allocation.allocation.id, Some("../outside"))
+                .unwrap_err()
+                .code,
+            "execution_workspace_relative_cwd_invalid"
+        );
+        assert_eq!(
+            materializer
+                .bind_allocation(&allocation.allocation.id, Some("missing"))
+                .unwrap_err()
+                .code,
+            "execution_workspace_relative_cwd_unavailable"
+        );
+        assert_eq!(
+            materializer
+                .bind_allocation(&allocation.allocation.id, Some("inside/file.txt"))
+                .unwrap_err()
+                .code,
+            "execution_workspace_relative_cwd_escape_rejected"
+        );
+
+        #[cfg(unix)]
+        {
+            std::os::unix::fs::symlink("/tmp", allocation.workspace_root().join("escape")).unwrap();
+            assert_eq!(
+                materializer
+                    .bind_allocation(&allocation.allocation.id, Some("escape"))
+                    .unwrap_err()
+                    .code,
+                "execution_workspace_relative_cwd_escape_rejected"
+            );
+        }
+    }
+
     #[test]
     fn cleanup_removes_worktree_and_updates_record() {
         let repo = create_clean_repo();

crates/worker-runtime/src/http_server.rs

@@ -864,6 +864,7 @@ mod tests {
             },
             initial_input: None,
             execution_workspace: None,
+            execution_workspace_allocation: None,
         }
     }
 
@@ -1148,6 +1149,7 @@ mod ws_tests {
             },
             initial_input: None,
             execution_workspace: None,
+            execution_workspace_allocation: None,
         }
     }
 

crates/worker-runtime/src/runtime.rs

@@ -1594,6 +1594,7 @@ mod tests {
             },
             initial_input: None,
             execution_workspace: None,
+            execution_workspace_allocation: None,
         }
     }
 

crates/worker-runtime/src/worker_backend.rs

@@ -374,8 +374,17 @@ where
         }
 
         let mut request = request;
-        let execution_workspace = match request.request.execution_workspace.as_ref() {
+        let execution_workspace = match (
-            Some(workspace_request) => {
+            request.request.execution_workspace.as_ref(),
+            request.request.execution_workspace_allocation.as_ref(),
+        ) {
+            (Some(_), Some(_)) => {
+                return WorkerExecutionSpawnResult::Rejected(WorkerExecutionResult::rejected(
+                    WorkerExecutionOperation::Spawn,
+                    "worker spawn cannot specify both execution_workspace and execution_workspace_allocation",
+                ));
+            }
+            (Some(workspace_request), None) => {
                 let Some(materializer) = self.execution_workspace_materializer.as_ref() else {
                     return WorkerExecutionSpawnResult::Rejected(WorkerExecutionResult::rejected(
                         WorkerExecutionOperation::Spawn,
@@ -397,7 +406,32 @@ where
                     }
                 }
             }
-            None => None,
+            (None, Some(allocation)) => {
+                let Some(materializer) = self.execution_workspace_materializer.as_ref() else {
+                    return WorkerExecutionSpawnResult::Rejected(WorkerExecutionResult::rejected(
+                        WorkerExecutionOperation::Spawn,
+                        "execution workspace allocation requested, but no materializer is configured for this runtime backend",
+                    ));
+                };
+                match materializer.bind_allocation(
+                    &allocation.allocation_id,
+                    allocation.relative_cwd.as_deref(),
+                ) {
+                    Ok(binding) => {
+                        request.execution_workspace = Some(binding.clone());
+                        Some(binding)
+                    }
+                    Err(error) => {
+                        return WorkerExecutionSpawnResult::Rejected(
+                            WorkerExecutionResult::rejected(
+                                WorkerExecutionOperation::Spawn,
+                                error.to_string(),
+                            ),
+                        );
+                    }
+                }
+            }
+            (None, None) => None,
         };
 
         let factory = self.factory.clone();
@@ -747,6 +781,7 @@ mod tests {
             },
             initial_input: None,
             execution_workspace: None,
+            execution_workspace_allocation: None,
         }
     }
 

crates/workspace-server/src/companion.rs

@@ -389,6 +389,7 @@ fn spawn_companion_worker(runtime: &RuntimeRegistry) -> CompanionWorkerState {
             initial_input: None,
             execution_workspace: None,
             resolved_execution_workspace: None,
+            resolved_execution_workspace_allocation: None,
         },
     );
 

crates/workspace-server/src/hosts.rs

@@ -12,7 +12,8 @@ use std::{
     time::Duration,
 };
 use worker_runtime::catalog::{
-    ConfigBundleRef, CreateWorkerRequest, ExecutionWorkspaceRequest, ProfileSelector,
+    ConfigBundleRef, CreateWorkerRequest, ExecutionWorkspaceAllocationClaim,
+    ExecutionWorkspaceRequest, ExecutionWorkspaceSummary, ProfileSelector,
     WorkerDetail as EmbeddedWorkerDetail, WorkerStatus as EmbeddedWorkerStatus,
 };
 use worker_runtime::config_bundle::{
@@ -238,6 +239,8 @@ pub struct WorkerSummary {
     pub last_seen_at: Option<String>,
     pub implementation: WorkerImplementationSummary,
     pub capabilities: WorkerCapabilitySummary,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub execution_workspace: Option<ExecutionWorkspaceSummary>,
     pub diagnostics: Vec<RuntimeDiagnostic>,
 }
 
@@ -299,6 +302,8 @@ pub struct WorkerSpawnRequest {
     pub execution_workspace: Option<WorkerSpawnExecutionWorkspaceRequest>,
     #[serde(skip, default)]
     pub resolved_execution_workspace: Option<ExecutionWorkspaceRequest>,
+    #[serde(skip, default)]
+    pub resolved_execution_workspace_allocation: Option<ExecutionWorkspaceAllocationClaim>,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
@@ -1138,6 +1143,11 @@ impl EmbeddedWorkerRuntime {
                 can_stop: self.can_stop_embedded_worker(summary.status, &summary.execution),
                 can_spawn_followup: false,
             },
+            execution_workspace: summary
+                .execution
+                .execution_workspace
+                .clone()
+                .map(|status| status.summary),
             diagnostics: embedded_worker_projection_diagnostics(&summary.execution),
         }
     }
@@ -1167,6 +1177,11 @@ impl EmbeddedWorkerRuntime {
                 can_stop: self.can_stop_embedded_worker(detail.status, &detail.execution),
                 can_spawn_followup: false,
             },
+            execution_workspace: detail
+                .execution
+                .execution_workspace
+                .clone()
+                .map(|status| status.summary),
             diagnostics: embedded_worker_projection_diagnostics(&detail.execution),
         }
     }
@@ -1342,6 +1357,7 @@ impl WorkspaceWorkerRuntime for EmbeddedWorkerRuntime {
             config_bundle,
             initial_input: request.initial_input.clone(),
             execution_workspace: request.resolved_execution_workspace.clone(),
+            execution_workspace_allocation: request.resolved_execution_workspace_allocation.clone(),
         };
         match self.runtime.create_worker(create_request) {
             Ok(detail) => {
@@ -1817,6 +1833,7 @@ impl RemoteWorkerRuntime {
                 can_stop: runtime_worker_can_stop(true, summary.status, &summary.execution),
                 can_spawn_followup: false,
             },
+            execution_workspace: summary.execution.execution_workspace.clone().map(|status| status.summary),
             diagnostics: vec![diagnostic(
                 "remote_runtime_projection",
                 DiagnosticSeverity::Info,
@@ -1850,6 +1867,7 @@ impl RemoteWorkerRuntime {
                 can_stop: runtime_worker_can_stop(true, detail.status, &detail.execution),
                 can_spawn_followup: false,
             },
+            execution_workspace: detail.execution.execution_workspace.clone().map(|status| status.summary),
             diagnostics: vec![diagnostic(
                 "remote_runtime_projection",
                 DiagnosticSeverity::Info,
@@ -2015,6 +2033,7 @@ impl WorkspaceWorkerRuntime for RemoteWorkerRuntime {
             config_bundle,
             initial_input: request.initial_input.clone(),
             execution_workspace: request.resolved_execution_workspace.clone(),
+            execution_workspace_allocation: request.resolved_execution_workspace_allocation.clone(),
         };
         match self.post_json::<_, RuntimeHttpWorkerResponse>("/v1/workers", &create) {
             Ok(response) => WorkerSpawnResult {
@@ -2825,6 +2844,7 @@ pub fn placeholder_worker(host_id: impl Into<String>) -> WorkerSummary {
             can_stop: false,
             can_spawn_followup: false,
         },
+        execution_workspace: None,
         diagnostics: vec![diagnostic(
             "runtime_capability_unsupported",
             DiagnosticSeverity::Info,
@@ -3020,6 +3040,7 @@ mod tests {
                         can_stop: false,
                         can_spawn_followup: false,
                     },
+                    execution_workspace: None,
                     diagnostics: Vec::new(),
                 }],
             }
@@ -3172,6 +3193,7 @@ mod tests {
             initial_input: None,
             execution_workspace: None,
             resolved_execution_workspace: None,
+            resolved_execution_workspace_allocation: None,
         }
     }
 
@@ -3303,6 +3325,7 @@ mod tests {
                     initial_input: None,
                     execution_workspace: None,
                     resolved_execution_workspace: None,
+                    resolved_execution_workspace_allocation: None,
                 },
             )
             .unwrap();
@@ -3404,6 +3427,7 @@ mod tests {
                     initial_input: None,
                     execution_workspace: None,
                     resolved_execution_workspace: None,
+                    resolved_execution_workspace_allocation: None,
                 },
             )
             .unwrap();
@@ -3434,6 +3458,7 @@ mod tests {
                     initial_input: None,
                     execution_workspace: None,
                     resolved_execution_workspace: None,
+                    resolved_execution_workspace_allocation: None,
                 },
             )
             .unwrap();

crates/workspace-server/src/server.rs

@@ -12,7 +12,9 @@ use chrono::{SecondsFormat, Utc};
 use futures::StreamExt;
 use serde::{Deserialize, Serialize};
 use tokio::net::TcpListener;
-use worker_runtime::execution_workspace::LocalGitWorktreeMaterializer;
+use worker_runtime::execution_workspace::{
+    ExecutionWorkspaceMaterializer, LocalGitWorktreeMaterializer,
+};
 use worker_runtime::worker_backend::WorkerRuntimeExecutionBackend;
 
 use crate::companion::{
@@ -43,7 +45,8 @@ use crate::repositories::{
 use crate::store::{ControlPlaneStore, WorkspaceRecord};
 use crate::{Error, Result};
 use worker_runtime::catalog::{
-    ConfigBundleRef, DirtyStatePolicy, ExecutionWorkspaceRepository, ExecutionWorkspaceRequest,
+    ConfigBundleRef, DirtyStatePolicy, ExecutionWorkspaceAllocationClaim,
+    ExecutionWorkspaceRepository, ExecutionWorkspaceRequest, ExecutionWorkspaceSummary,
     MaterializerKind, ProfileSelector, RepositorySelector as RuntimeRepositorySelector,
 };
 use worker_runtime::config_bundle::ConfigBundle;
@@ -151,10 +154,14 @@ pub struct WorkspaceApi {
     runtime: Arc<RuntimeRegistry>,
     companion: Arc<CompanionConsole>,
     observation_proxy: BackendObservationProxy,
+    execution_workspace_materializer: Arc<LocalGitWorktreeMaterializer>,
 }
 
 impl WorkspaceApi {
     pub async fn new(config: ServerConfig, store: Arc<dyn ControlPlaneStore>) -> Result<Self> {
+        let materializer = Arc::new(LocalGitWorktreeMaterializer::new(
+            config.embedded_runtime_store_root.clone(),
+        ));
         let execution_backend =
             WorkerRuntimeExecutionBackend::from_workspace(config.workspace_root.clone())
                 .map_err(|err| {
@@ -162,9 +169,7 @@ impl WorkspaceApi {
                         "failed to initialize embedded Worker backend: {err}"
                     ))
                 })?
-                .with_execution_workspace_materializer(LocalGitWorktreeMaterializer::new(
+                .with_execution_workspace_materializer((*materializer).clone());
-                    config.embedded_runtime_store_root.clone(),
-                ));
         Self::new_with_execution_backend(config, store, Arc::new(execution_backend)).await
     }
 
@@ -199,6 +204,9 @@ impl WorkspaceApi {
         let runtime = Arc::new(runtime);
         let companion = Arc::new(CompanionConsole::new(runtime.clone()));
         let observation_proxy = BackendObservationProxy::new(config.runtime_event_sources.clone());
+        let execution_workspace_materializer = Arc::new(LocalGitWorktreeMaterializer::new(
+            config.embedded_runtime_store_root.clone(),
+        ));
         Ok(Self {
             records: LocalProjectRecordReader::new(config.workspace_root.clone()),
             config,
@@ -206,6 +214,7 @@ impl WorkspaceApi {
             runtime,
             companion,
             observation_proxy,
+            execution_workspace_materializer,
         })
     }
 
@@ -261,6 +270,14 @@ pub fn build_router(api: WorkspaceApi) -> Router {
         )
         .route("/api/hosts", get(list_hosts))
         .route("/api/w/{workspace_id}/hosts", get(scoped_list_hosts))
+        .route(
+            "/api/w/{workspace_id}/execution-workspaces",
+            get(scoped_list_execution_workspaces).post(scoped_create_execution_workspace),
+        )
+        .route(
+            "/api/w/{workspace_id}/execution-workspaces/{allocation_id}",
+            get(scoped_execution_workspace_detail).delete(scoped_cleanup_execution_workspace),
+        )
         .route("/api/runtimes", get(list_runtimes))
         .route("/api/w/{workspace_id}/runtimes", get(scoped_list_runtimes))
         .route(
@@ -530,6 +547,8 @@ pub struct WorkerLaunchOptionsResponse {
     pub workspace_id: String,
     pub runtimes: Vec<WorkerLaunchRuntimeOption>,
     pub profiles: Vec<WorkerLaunchProfileCandidate>,
+    pub repositories: Vec<ExecutionWorkspaceRepositoryOption>,
+    pub execution_workspaces: Vec<ExecutionWorkspaceSummary>,
     pub diagnostics: Vec<RuntimeDiagnostic>,
 }
 
@@ -550,6 +569,68 @@ pub struct WorkerLaunchProfileCandidate {
     pub description: String,
 }
 
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ExecutionWorkspaceRepositoryOption {
+    pub id: String,
+    pub display_name: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub default_selector: Option<String>,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, Default)]
+pub struct BrowserExecutionWorkspaceCreatePolicy {
+    #[serde(default)]
+    pub dirty_state: BrowserExecutionWorkspaceDirtyStatePolicy,
+    #[serde(default)]
+    pub cleanup: BrowserExecutionWorkspaceCleanupPolicy,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, Default)]
+#[serde(rename_all = "snake_case")]
+pub enum BrowserExecutionWorkspaceDirtyStatePolicy {
+    #[default]
+    CleanPointOnly,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, Default)]
+#[serde(rename_all = "snake_case")]
+pub enum BrowserExecutionWorkspaceCleanupPolicy {
+    #[default]
+    ManualOrWorkerStop,
+}
+
+#[derive(Debug, Deserialize)]
+#[serde(deny_unknown_fields)]
+pub struct BrowserExecutionWorkspaceCreateRequest {
+    pub repository_id: String,
+    #[serde(default)]
+    pub selector: Option<String>,
+    #[serde(default)]
+    pub policy: BrowserExecutionWorkspaceCreatePolicy,
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+pub struct BrowserExecutionWorkspaceListResponse {
+    pub workspace_id: String,
+    pub items: Vec<ExecutionWorkspaceSummary>,
+    pub diagnostics: Vec<RuntimeDiagnostic>,
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+pub struct BrowserExecutionWorkspaceDetailResponse {
+    pub workspace_id: String,
+    pub item: ExecutionWorkspaceSummary,
+    pub diagnostics: Vec<RuntimeDiagnostic>,
+}
+
+#[derive(Debug, Deserialize)]
+#[serde(deny_unknown_fields)]
+pub struct BrowserWorkerExecutionWorkspaceSelection {
+    pub allocation_id: String,
+    #[serde(default)]
+    pub relative_cwd: Option<String>,
+}
+
 #[derive(Debug, Deserialize)]
 #[serde(deny_unknown_fields)]
 pub struct BrowserCreateWorkerRequest {
@@ -558,7 +639,7 @@ pub struct BrowserCreateWorkerRequest {
     pub profile: String,
     pub initial_text: String,
     #[serde(default)]
-    pub repository_id: Option<String>,
+    pub execution_workspace: Option<BrowserWorkerExecutionWorkspaceSelection>,
 }
 
 #[derive(Debug, Serialize, Deserialize)]
@@ -660,6 +741,12 @@ struct ScopedRuntimePath {
     runtime_id: String,
 }
 
+#[derive(Debug, Deserialize)]
+struct ScopedExecutionWorkspacePath {
+    workspace_id: String,
+    allocation_id: String,
+}
+
 #[derive(Debug, Deserialize)]
 struct ScopedConfigBundlePath {
     workspace_id: String,
@@ -797,6 +884,87 @@ async fn scoped_get_worker_launch_options(
     get_worker_launch_options(State(api)).await
 }
 
+async fn scoped_list_execution_workspaces(
+    State(api): State<WorkspaceApi>,
+    AxumPath(path): AxumPath<ScopedWorkspacePath>,
+) -> ApiResult<Json<BrowserExecutionWorkspaceListResponse>> {
+    validate_workspace_scope(&api, &path.workspace_id)?;
+    let items = execution_workspace_summaries(&api)?;
+    Ok(Json(BrowserExecutionWorkspaceListResponse {
+        workspace_id: api.config.workspace_id.clone(),
+        items,
+        diagnostics: Vec::new(),
+    }))
+}
+
+async fn scoped_create_execution_workspace(
+    State(api): State<WorkspaceApi>,
+    AxumPath(path): AxumPath<ScopedWorkspacePath>,
+    Json(request): Json<BrowserExecutionWorkspaceCreateRequest>,
+) -> ApiResult<Json<BrowserExecutionWorkspaceDetailResponse>> {
+    validate_workspace_scope(&api, &path.workspace_id)?;
+    let workspace_request = execution_workspace_request_for_browser(&api, request)?;
+    let binding = api
+        .execution_workspace_materializer
+        .preallocate(&workspace_request)
+        .map_err(|diagnostic| {
+            ApiError::from(Error::RuntimeOperationFailed {
+                runtime_id: EMBEDDED_WORKER_RUNTIME_ID.to_string(),
+                code: diagnostic.code,
+                message: diagnostic.message,
+            })
+        })?;
+    Ok(Json(BrowserExecutionWorkspaceDetailResponse {
+        workspace_id: api.config.workspace_id.clone(),
+        item: binding.status().summary,
+        diagnostics: Vec::new(),
+    }))
+}
+
+async fn scoped_execution_workspace_detail(
+    State(api): State<WorkspaceApi>,
+    AxumPath(path): AxumPath<ScopedExecutionWorkspacePath>,
+) -> ApiResult<Json<BrowserExecutionWorkspaceDetailResponse>> {
+    validate_workspace_scope(&api, &path.workspace_id)?;
+    let status = api
+        .execution_workspace_materializer
+        .allocation_status(&path.allocation_id)
+        .map_err(|diagnostic| {
+            ApiError::from(Error::RuntimeOperationFailed {
+                runtime_id: EMBEDDED_WORKER_RUNTIME_ID.to_string(),
+                code: diagnostic.code,
+                message: diagnostic.message,
+            })
+        })?;
+    Ok(Json(BrowserExecutionWorkspaceDetailResponse {
+        workspace_id: api.config.workspace_id.clone(),
+        item: status.summary,
+        diagnostics: Vec::new(),
+    }))
+}
+
+async fn scoped_cleanup_execution_workspace(
+    State(api): State<WorkspaceApi>,
+    AxumPath(path): AxumPath<ScopedExecutionWorkspacePath>,
+) -> ApiResult<Json<BrowserExecutionWorkspaceDetailResponse>> {
+    validate_workspace_scope(&api, &path.workspace_id)?;
+    let status = api
+        .execution_workspace_materializer
+        .cleanup_allocation(&path.allocation_id)
+        .map_err(|diagnostic| {
+            ApiError::from(Error::RuntimeOperationFailed {
+                runtime_id: EMBEDDED_WORKER_RUNTIME_ID.to_string(),
+                code: diagnostic.code,
+                message: diagnostic.message,
+            })
+        })?;
+    Ok(Json(BrowserExecutionWorkspaceDetailResponse {
+        workspace_id: api.config.workspace_id.clone(),
+        item: status.summary,
+        diagnostics: Vec::new(),
+    }))
+}
+
 async fn scoped_get_runtime_connection_settings(
     State(api): State<WorkspaceApi>,
     AxumPath(path): AxumPath<ScopedWorkspacePath>,
@@ -1428,35 +1596,6 @@ fn configured_execution_workspace_request(
     ))
 }
 
-fn default_execution_workspace_request(
-    config: &ServerConfig,
-    repository_id: Option<&str>,
-) -> Result<Option<ExecutionWorkspaceRequest>> {
-    let repository = match repository_id {
-        Some(id) => config
-            .repositories
-            .iter()
-            .find(|repository| repository.id == id)
-            .ok_or_else(|| {
-                Error::Config(format!(
-                    "unknown repository id `{id}` for Worker execution workspace"
-                ))
-            })?,
-        None => match config.repositories.as_slice() {
-            [] => return Ok(None),
-            [repository] => repository,
-            repositories => repositories
-                .iter()
-                .find(|repository| repository.id == "main")
-                .unwrap_or(&repositories[0]),
-        },
-    };
-
-    Ok(Some(execution_workspace_request_from_repository(
-        repository, None,
-    )))
-}
-
 async fn create_workspace_worker(
     State(api): State<WorkspaceApi>,
     Json(request): Json<BrowserCreateWorkerRequest>,
@@ -1482,8 +1621,23 @@ async fn create_workspace_worker(
             content: initial_text,
         })
     };
-    let execution_workspace =
+    let resolved_execution_workspace_allocation =
-        default_execution_workspace_request(&api.config, request.repository_id.as_deref())?;
+        request
+            .execution_workspace
+            .map(|selection| ExecutionWorkspaceAllocationClaim {
+                allocation_id: selection.allocation_id,
+                relative_cwd: selection.relative_cwd,
+            });
+    if resolved_execution_workspace_allocation.is_some()
+        && request.runtime_id != EMBEDDED_WORKER_RUNTIME_ID
+    {
+        return Err(Error::RuntimeOperationFailed {
+            runtime_id: request.runtime_id.clone(),
+            code: "execution_workspace_runtime_unsupported".to_string(),
+            message: "preallocated execution workspaces are only supported by the embedded local runtime in v0".to_string(),
+        }
+        .into());
+    }
     let result = api
         .runtime
         .spawn_worker(
@@ -1497,7 +1651,8 @@ async fn create_workspace_worker(
                 profile: Some(profile_selector),
                 initial_input,
                 execution_workspace: None,
-                resolved_execution_workspace: execution_workspace,
+                resolved_execution_workspace: None,
+                resolved_execution_workspace_allocation,
             },
         )
         .map_err(|err| err.into_error())?;
@@ -2523,10 +2678,75 @@ fn worker_launch_options_response(api: &WorkspaceApi) -> WorkerLaunchOptionsResp
         workspace_id: api.config.workspace_id.clone(),
         runtimes,
         profiles: worker_profile_candidates(),
+        repositories: execution_workspace_repository_options(api),
+        execution_workspaces: execution_workspace_summaries(api).unwrap_or_default(),
         diagnostics: Vec::new(),
     }
 }
 
+fn execution_workspace_repository_options(
+    api: &WorkspaceApi,
+) -> Vec<ExecutionWorkspaceRepositoryOption> {
+    api.config
+        .repositories
+        .iter()
+        .map(|repository| ExecutionWorkspaceRepositoryOption {
+            id: repository.id.clone(),
+            display_name: repository
+                .display_name
+                .clone()
+                .unwrap_or_else(|| repository.id.clone()),
+            default_selector: repository.default_selector.clone(),
+        })
+        .collect()
+}
+
+fn execution_workspace_summaries(api: &WorkspaceApi) -> ApiResult<Vec<ExecutionWorkspaceSummary>> {
+    api.execution_workspace_materializer
+        .list_allocations()
+        .map(|items| items.into_iter().map(|status| status.summary).collect())
+        .map_err(|diagnostic| {
+            ApiError::from(Error::RuntimeOperationFailed {
+                runtime_id: EMBEDDED_WORKER_RUNTIME_ID.to_string(),
+                code: diagnostic.code,
+                message: diagnostic.message,
+            })
+        })
+}
+
+fn execution_workspace_request_for_browser(
+    api: &WorkspaceApi,
+    request: BrowserExecutionWorkspaceCreateRequest,
+) -> ApiResult<ExecutionWorkspaceRequest> {
+    let repository = api
+        .config
+        .repositories
+        .iter()
+        .find(|repository| repository.id == request.repository_id)
+        .ok_or_else(|| Error::UnknownRepository(request.repository_id.clone()))?;
+    let selector = request
+        .selector
+        .or_else(|| repository.default_selector.clone())
+        .filter(|selector| !selector.trim().is_empty());
+    match request.policy.dirty_state {
+        BrowserExecutionWorkspaceDirtyStatePolicy::CleanPointOnly => {}
+    }
+    match request.policy.cleanup {
+        BrowserExecutionWorkspaceCleanupPolicy::ManualOrWorkerStop => {}
+    }
+    Ok(ExecutionWorkspaceRequest {
+        repository: ExecutionWorkspaceRepository {
+            id: repository.id.clone(),
+            provider: "git".to_string(),
+            uri: repository.path.to_string_lossy().to_string(),
+            local_path: Some(repository.path.clone()),
+            selector: selector.map(RuntimeRepositorySelector),
+        },
+        materializer: MaterializerKind::LocalGitWorktree,
+        dirty_state_policy: DirtyStatePolicy::CleanPointOnly,
+    })
+}
+
 fn worker_profile_candidates() -> Vec<WorkerLaunchProfileCandidate> {
     vec![
         WorkerLaunchProfileCandidate {
@@ -3092,6 +3312,40 @@ mod tests {
         config
     }
 
+    fn init_clean_git_workspace(path: &std::path::Path) {
+        for args in [
+            vec!["init"],
+            vec!["config", "user.email", "test@example.invalid"],
+            vec!["config", "user.name", "Yoi Test"],
+        ] {
+            let status = std::process::Command::new("git")
+                .arg("-C")
+                .arg(path)
+                .args(args)
+                .status()
+                .unwrap();
+            assert!(status.success());
+        }
+        std::fs::write(path.join("README.md"), "clean\n").unwrap();
+        std::fs::write(
+            path.join(".gitignore"),
+            ".yoi/\n.test-embedded-runtime-store/\n",
+        )
+        .unwrap();
+        for args in [
+            vec!["add", "README.md", ".gitignore"],
+            vec!["commit", "-m", "init"],
+        ] {
+            let status = std::process::Command::new("git")
+                .arg("-C")
+                .arg(path)
+                .args(args)
+                .status()
+                .unwrap();
+            assert!(status.success());
+        }
+    }
+
     async fn test_app(workspace_root: impl Into<PathBuf>) -> Router {
         let store = SqliteWorkspaceStore::in_memory().unwrap();
         let api = WorkspaceApi::new_with_execution_backend(
@@ -3136,6 +3390,7 @@ mod tests {
             },
             initial_input: None,
             execution_workspace: None,
+            execution_workspace_allocation: None,
         }
     }
 
@@ -3150,6 +3405,45 @@ mod tests {
         (runtime, worker.worker_ref)
     }
 
+    #[tokio::test]
+    async fn browser_execution_workspace_preallocate_list_detail_and_cleanup_are_path_safe() {
+        let dir = tempfile::tempdir().unwrap();
+        init_clean_git_workspace(dir.path());
+        let app = test_app(dir.path()).await;
+        let workspace_path = format!("/api/w/{TEST_WORKSPACE_ID}/execution-workspaces");
+
+        let created = post_json(
+            app.clone(),
+            &workspace_path,
+            serde_json::json!({
+                "repository_id": TEST_REPOSITORY_ID,
+                "selector": "HEAD",
+                "policy": { "dirty_state": "clean_point_only", "cleanup": "manual_or_worker_stop" }
+            }),
+        )
+        .await;
+        let allocation_id = created["item"]["allocation_id"]
+            .as_str()
+            .unwrap()
+            .to_string();
+        assert_eq!(created["item"]["repository_id"], TEST_REPOSITORY_ID);
+        assert_eq!(created["item"]["requested_selector"], "HEAD");
+        assert_eq!(created["item"]["status"], "active");
+        let projected = serde_json::to_string(&created).unwrap();
+        assert!(!projected.contains(dir.path().to_string_lossy().as_ref()));
+
+        let list = get_json(app.clone(), &workspace_path).await;
+        assert_eq!(list["items"].as_array().unwrap().len(), 1);
+        assert_eq!(list["items"][0]["allocation_id"], allocation_id);
+
+        let detail_path = format!("{workspace_path}/{allocation_id}");
+        let detail = get_json(app.clone(), &detail_path).await;
+        assert_eq!(detail["item"]["allocation_id"], allocation_id);
+
+        let removed = request_json(app, "DELETE", &detail_path, None, StatusCode::OK).await;
+        assert_eq!(removed["item"]["status"], "removed");
+    }
+
     #[tokio::test]
     async fn runtime_connection_settings_add_delete_apply_live_registry() {
         let dir = tempfile::tempdir().unwrap();
@@ -4005,6 +4299,7 @@ mod tests {
                     initial_input: None,
                     execution_workspace: None,
                     resolved_execution_workspace: None,
+                    resolved_execution_workspace_allocation: None,
                 },
             )
             .expect("spawn worker");

web/workspace/src/lib/workspace-sidebar/WorkersNavSection.svelte

@@ -4,6 +4,7 @@
   import { buildBrowserCreateWorkerRequest, defaultWorkerLaunchForm } from './worker-launch';
   import type {
     BrowserCreateWorkerResponse,
+    BrowserExecutionWorkspaceCreateResponse,
     ListResponse,
     Worker,
     WorkerLaunchOptionsResponse,
@@ -35,6 +36,11 @@
   let runtimeId = $state('');
   let profile = $state('builtin:coder');
   let initialText = $state('');
+  let executionWorkspaceAllocationId = $state('');
+  let executionWorkspaceRepositoryId = $state('');
+  let executionWorkspaceSelector = $state('HEAD');
+  let relativeCwd = $state('');
+  let creatingWorkspace = $state(false);
 
   $effect(() => {
     if (!workspaceId) {
@@ -96,10 +102,18 @@
         display_name: displayName,
         profile,
         initial_text: initialText,
+        execution_workspace_allocation_id: executionWorkspaceAllocationId,
+        execution_workspace_repository_id: executionWorkspaceRepositoryId,
+        execution_workspace_selector: executionWorkspaceSelector,
+        relative_cwd: relativeCwd,
       });
       runtimeId = form.runtime_id;
       displayName = form.display_name;
       profile = form.profile;
+      executionWorkspaceAllocationId = form.execution_workspace_allocation_id;
+      executionWorkspaceRepositoryId = form.execution_workspace_repository_id;
+      executionWorkspaceSelector = form.execution_workspace_selector;
+      relativeCwd = form.relative_cwd;
     } catch (err) {
       if (err instanceof DOMException && err.name === 'AbortError') {
         return;
@@ -108,6 +122,39 @@
     }
   }
 
+  async function createExecutionWorkspace() {
+    if (!executionWorkspaceRepositoryId) {
+      submitError = 'select a repository before creating an execution workspace';
+      return;
+    }
+    creatingWorkspace = true;
+    submitError = null;
+    try {
+      const response = await fetch(workerApiPath('/execution-workspaces'), {
+        method: 'POST',
+        headers: { 'content-type': 'application/json' },
+        body: JSON.stringify({
+          repository_id: executionWorkspaceRepositoryId,
+          selector: executionWorkspaceSelector || null,
+          policy: { dirty_state: 'clean_point_only', cleanup: 'manual_or_worker_stop' },
+        }),
+      });
+      if (!response.ok) {
+        throw new Error(await responseErrorMessage(response, 'execution workspace create failed'));
+      }
+      const payload = (await response.json()) as BrowserExecutionWorkspaceCreateResponse;
+      const items = options?.execution_workspaces ?? [];
+      options = options
+        ? { ...options, execution_workspaces: [...items.filter((item) => item.allocation_id !== payload.item.allocation_id), payload.item] }
+        : options;
+      executionWorkspaceAllocationId = payload.item.allocation_id;
+    } catch (err) {
+      submitError = err instanceof Error ? err.message : 'execution workspace create failed';
+    } finally {
+      creatingWorkspace = false;
+    }
+  }
+
   async function createWorker() {
     if (!workspaceId) {
       submitError = 'workspace id is unavailable';
@@ -125,6 +172,10 @@
           display_name: displayName,
           profile,
           initial_text: initialText,
+          execution_workspace_allocation_id: executionWorkspaceAllocationId,
+          execution_workspace_repository_id: executionWorkspaceRepositoryId,
+          execution_workspace_selector: executionWorkspaceSelector,
+          relative_cwd: relativeCwd,
         })),
       });
       if (!response.ok) {
@@ -200,6 +251,43 @@
           {/if}
         </select>
       </label>
+      <fieldset class="worker-execution-workspace">
+        <legend>Execution workspace</legend>
+        <label>
+          <span>Allocation</span>
+          <select bind:value={executionWorkspaceAllocationId}>
+            <option value="">No allocation selected</option>
+            {#each options?.execution_workspaces ?? [] as workspace}
+              <option value={workspace.allocation_id} disabled={workspace.status !== 'active'}>
+                {workspace.repository_id} · {workspace.requested_selector ?? 'HEAD'} · {workspace.resolved_commit.slice(0, 12)} · {workspace.status}
+              </option>
+            {/each}
+          </select>
+        </label>
+        <label>
+          <span>Repository for new allocation</span>
+          <select bind:value={executionWorkspaceRepositoryId}>
+            {#if options?.repositories.length}
+              {#each options.repositories as repository}
+                <option value={repository.id}>{repository.display_name}</option>
+              {/each}
+            {:else}
+              <option value="" disabled>No configured repositories</option>
+            {/if}
+          </select>
+        </label>
+        <label>
+          <span>Selector</span>
+          <input bind:value={executionWorkspaceSelector} autocomplete="off" placeholder="HEAD" />
+        </label>
+        <button type="button" disabled={creatingWorkspace || !executionWorkspaceRepositoryId} onclick={() => void createExecutionWorkspace()}>
+          {creatingWorkspace ? 'Allocating…' : 'Create execution workspace'}
+        </button>
+        <label>
+          <span>Relative cwd</span>
+          <input bind:value={relativeCwd} autocomplete="off" placeholder="Optional path inside allocation" />
+        </label>
+      </fieldset>
       <label>
         <span>Initial text</span>
         <textarea bind:value={initialText} rows="3" placeholder="Optional first instruction"></textarea>
@@ -210,7 +298,7 @@
       {#if submitError}
         <p class="section-state error">{submitError}</p>
       {/if}
-      <button type="submit" disabled={submitting || !runtimeId || !profile}>
+      <button type="submit" disabled={submitting || !runtimeId || !profile || !executionWorkspaceAllocationId}>
         {submitting ? 'Starting…' : 'Start Coding Worker'}
       </button>
     </form>
@@ -234,6 +322,7 @@
             </span>
             <span class="item-meta">
               {worker.role ? `${worker.role} · ` : ''}{worker.state} · {worker.status} · 🖥 {worker.host_id}
+              {worker.execution_workspace ? ` · ws:${worker.execution_workspace.repository_id}@${worker.execution_workspace.resolved_commit.slice(0, 8)}` : ''}
             </span>
           </a>
         </li>

web/workspace/src/lib/workspace-sidebar/types.ts

@@ -88,6 +88,7 @@ export type Worker = {
   last_seen_at?: string | null;
   implementation: { kind: string; display_hint: string };
   capabilities: WorkerCapabilities;
+  execution_workspace?: ExecutionWorkspaceSummary | null;
   diagnostics: Diagnostic[];
 };
 
@@ -108,10 +109,61 @@ export type WorkerLaunchProfileCandidate = {
   description: string;
 };
 
+export type ExecutionWorkspaceRepositoryOption = {
+  id: string;
+  display_name: string;
+  default_selector?: string | null;
+};
+
+export type ExecutionWorkspaceSummary = {
+  allocation_id: string;
+  repository_id: string;
+  requested_selector?: string | null;
+  materializer_kind: string;
+  dirty_state_policy: string;
+  resolved_commit: string;
+  resolved_tree?: string | null;
+  status: string;
+  cleanup_policy: string;
+  cleanup_target: {
+    kind: string;
+    allocation_id: string;
+    repository_id: string;
+  };
+};
+
+export type BrowserExecutionWorkspaceCreateResponse = {
+  workspace_id: string;
+  item: ExecutionWorkspaceSummary;
+  diagnostics: Diagnostic[];
+};
+
+export type BrowserExecutionWorkspaceListResponse = {
+  workspace_id: string;
+  items: ExecutionWorkspaceSummary[];
+  diagnostics: Diagnostic[];
+};
+
+export type BrowserWorkerExecutionWorkspaceSelection = {
+  allocation_id: string;
+  relative_cwd?: string | null;
+};
+
+export type BrowserExecutionWorkspaceCreateRequest = {
+  repository_id: string;
+  selector?: string | null;
+  policy?: {
+    dirty_state?: 'clean_point_only';
+    cleanup?: 'manual_or_worker_stop';
+  };
+};
+
 export type WorkerLaunchOptionsResponse = {
   workspace_id: string;
   runtimes: WorkerLaunchRuntimeOption[];
   profiles: WorkerLaunchProfileCandidate[];
+  repositories: ExecutionWorkspaceRepositoryOption[];
+  execution_workspaces: ExecutionWorkspaceSummary[];
   diagnostics: Diagnostic[];
 };
 

web/workspace/src/lib/workspace-sidebar/worker-launch.test.ts

@@ -1,18 +1,15 @@
-import {
+import { buildBrowserCreateWorkerRequest, defaultWorkerLaunchForm } from './worker-launch.ts';
-  buildBrowserCreateWorkerRequest,
-  defaultWorkerLaunchForm,
-  type WorkerLaunchFormState,
-} from './worker-launch.ts';
-
 import type { WorkerLaunchOptionsResponse } from './types.ts';
 
 declare const Deno: {
-  test(name: string, fn: () => void): void;
+  test(name: string, fn: () => Promise<void> | void): void;
 };
 
-function assert(condition: unknown, message: string): asserts condition {
+function assertEquals<T>(actual: T, expected: T): void {
-  if (!condition) {
+  const actualJson = JSON.stringify(actual);
-    throw new Error(message);
+  const expectedJson = JSON.stringify(expected);
+  if (actualJson !== expectedJson) {
+    throw new Error(`Expected ${expectedJson}, got ${actualJson}`);
   }
 }
 
@@ -20,64 +17,86 @@ const options: WorkerLaunchOptionsResponse = {
   workspace_id: 'workspace',
   runtimes: [
     {
-      runtime_id: 'remote-runtime',
+      runtime_id: 'remote',
-      display_name: 'Remote Runtime',
+      display_name: 'Remote',
-      built_in: false,
-      can_spawn_worker: false,
       status: 'active',
+      can_spawn_worker: true,
+      built_in: false,
       diagnostics: [],
     },
     {
-      runtime_id: 'embedded-worker-runtime',
+      runtime_id: 'embedded',
-      display_name: 'Embedded Runtime',
+      display_name: 'Embedded',
-      built_in: true,
-      can_spawn_worker: true,
       status: 'active',
+      can_spawn_worker: true,
+      built_in: false,
       diagnostics: [],
     },
   ],
   profiles: [
+    { id: 'builtin:companion', label: 'Companion', description: 'chat' },
+    { id: 'builtin:coder', label: 'Coder', description: 'code' },
+  ],
+  repositories: [
+    { id: 'repo', display_name: 'Repo', default_selector: 'HEAD' },
+  ],
+  execution_workspaces: [
     {
-      id: 'runtime_default',
+      allocation_id: 'alloc-1-repo',
-      label: 'Runtime default',
+      repository_id: 'repo',
-      description: 'Runtime default profile.',
+      requested_selector: 'HEAD',
-    },
+      materializer_kind: 'local_git_worktree',
-    {
+      dirty_state_policy: 'clean_point_only',
-      id: 'builtin:coder',
+      resolved_commit: '0123456789abcdef',
-      label: 'Coding Worker',
+      status: 'active',
-      description: 'Coding role.',
+      cleanup_policy: 'manual_or_worker_stop',
+      cleanup_target: { kind: 'git_worktree', allocation_id: 'alloc-1-repo', repository_id: 'repo' },
     },
   ],
   diagnostics: [],
 };
 
-Deno.test('new worker form defaults to backend-published runtime and profile candidates', () => {
+Deno.test('defaultWorkerLaunchForm chooses active runtime, coder profile, repository, and workspace', () => {
-  const current: WorkerLaunchFormState = {
+  const form = defaultWorkerLaunchForm(options, {
     runtime_id: '',
     display_name: '',
-    profile: 'free-text-profile',
+    profile: '',
-    initial_text: 'start here',
+    initial_text: 'hello',
-  };
+    execution_workspace_allocation_id: '',
-
+    execution_workspace_repository_id: '',
-  const form = defaultWorkerLaunchForm(options, current);
+    execution_workspace_selector: '',
-  assert(form.runtime_id === 'embedded-worker-runtime', 'should choose spawn-capable runtime');
+    relative_cwd: '',
-  assert(form.profile === 'builtin:coder', 'should choose backend-published coder profile');
-  assert(form.display_name === 'Coding Worker', 'should derive default display name');
-  assert(form.initial_text === 'start here', 'should preserve initial text');
   });
 
-Deno.test('new worker submit payload exposes only browser contract fields', () => {
+  assertEquals(form.runtime_id, 'remote');
+  assertEquals(form.display_name, 'Coding Worker');
+  assertEquals(form.profile, 'builtin:coder');
+  assertEquals(form.initial_text, 'hello');
+  assertEquals(form.execution_workspace_allocation_id, 'alloc-1-repo');
+  assertEquals(form.execution_workspace_repository_id, 'repo');
+  assertEquals(form.execution_workspace_selector, 'HEAD');
+});
+
+Deno.test('buildBrowserCreateWorkerRequest sends allocation id and relative cwd only', () => {
   const request = buildBrowserCreateWorkerRequest({
-    runtime_id: 'embedded-worker-runtime',
+    runtime_id: 'embedded',
-    display_name: 'Coding Worker',
+    display_name: 'Worker',
     profile: 'builtin:coder',
-    initial_text: 'implement ticket',
+    initial_text: 'go',
+    execution_workspace_allocation_id: 'alloc-1-repo',
+    execution_workspace_repository_id: 'repo',
+    execution_workspace_selector: 'main',
+    relative_cwd: 'crates/yoi',
   });
 
-  assert(
+  assertEquals(request, {
-    JSON.stringify(Object.keys(request).sort()) ===
+    runtime_id: 'embedded',
-      JSON.stringify(['display_name', 'initial_text', 'profile', 'runtime_id'].sort()),
+    display_name: 'Worker',
-    'submit payload should contain only Browser-facing worker create fields',
+    profile: 'builtin:coder',
-  );
+    initial_text: 'go',
-  assert(!('kind' in request), 'kind must not be exposed as a Browser request field');
+    execution_workspace: {
+      allocation_id: 'alloc-1-repo',
+      relative_cwd: 'crates/yoi',
+    },
+  });
 });

web/workspace/src/lib/workspace-sidebar/worker-launch.ts

@@ -1,13 +1,23 @@
-import type { WorkerLaunchOptionsResponse } from './types';
+import type { BrowserWorkerExecutionWorkspaceSelection, WorkerLaunchOptionsResponse } from './types';
 
 export type WorkerLaunchFormState = {
   runtime_id: string;
   display_name: string;
   profile: string;
   initial_text: string;
+  execution_workspace_allocation_id: string;
+  execution_workspace_repository_id: string;
+  execution_workspace_selector: string;
+  relative_cwd: string;
 };
 
-export type BrowserCreateWorkerRequest = WorkerLaunchFormState;
+export type BrowserCreateWorkerRequest = {
+  runtime_id: string;
+  display_name: string;
+  profile: string;
+  initial_text: string;
+  execution_workspace?: BrowserWorkerExecutionWorkspaceSelection;
+};
 
 export function defaultWorkerLaunchForm(
   options: WorkerLaunchOptionsResponse | null,
@@ -18,6 +28,10 @@ export function defaultWorkerLaunchForm(
     ?? options?.runtimes[0];
   const preferredProfile = options?.profiles.find((candidate) => candidate.id === 'builtin:coder')
     ?? options?.profiles[0];
+  const preferredExecutionWorkspace = options?.execution_workspaces.find((workspace) => workspace.status === 'active')
+    ?? options?.execution_workspaces[0];
+  const preferredRepository = options?.repositories.find((repository) => repository.id === current.execution_workspace_repository_id)
+    ?? options?.repositories[0];
 
   return {
     runtime_id: current.runtime_id || preferredRuntime?.runtime_id || '',
@@ -26,16 +40,34 @@ export function defaultWorkerLaunchForm(
       ? current.profile
       : preferredProfile?.id || '',
     initial_text: current.initial_text,
+    execution_workspace_allocation_id: options?.execution_workspaces.some(
+      (workspace) => workspace.allocation_id === current.execution_workspace_allocation_id,
+    )
+      ? current.execution_workspace_allocation_id
+      : preferredExecutionWorkspace?.allocation_id || '',
+    execution_workspace_repository_id: current.execution_workspace_repository_id || preferredRepository?.id || '',
+    execution_workspace_selector: current.execution_workspace_selector || preferredRepository?.default_selector || 'HEAD',
+    relative_cwd: current.relative_cwd,
   };
 }
 
 export function buildBrowserCreateWorkerRequest(
   form: WorkerLaunchFormState,
 ): BrowserCreateWorkerRequest {
-  return {
+  const request: BrowserCreateWorkerRequest = {
     runtime_id: form.runtime_id,
     display_name: form.display_name,
     profile: form.profile,
     initial_text: form.initial_text,
   };
+  if (form.execution_workspace_allocation_id) {
+    request.execution_workspace = {
+      allocation_id: form.execution_workspace_allocation_id,
+    };
+    const relativeCwd = form.relative_cwd.trim();
+    if (relativeCwd) {
+      request.execution_workspace.relative_cwd = relativeCwd;
+    }
+  }
+  return request;
 }