Merge branch 'work/00001KY8KRJKK-virtual-config-tree' into develop

Cargo.lock

@@ -589,6 +589,31 @@ dependencies = [
  "static_assertions",
 ]
 
+[[package]]
+name = "config-source"
+version = "0.1.0"
+dependencies = [
+ "decodal",
+ "decodal-language-service",
+ "decodal-language-tools",
+ "pretty_assertions",
+ "serde",
+ "serde_json",
+ "sha2 0.11.0",
+ "thiserror 2.0.18",
+ "ts-rs",
+]
+
+[[package]]
+name = "config-source-wasm"
+version = "0.1.0"
+dependencies = [
+ "config-source",
+ "serde",
+ "serde-wasm-bindgen",
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "const-oid"
 version = "0.10.2"
@@ -961,9 +986,29 @@ checksum = "092966b41edc516079bdf31ec78a2e0588d1d0c08f78b91d8307215928642b2b"
 
 [[package]]
 name = "decodal"
-version = "0.1.1"
+version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4291c87ce887fafc0acf9f40f4bc17e111457e9d62f1b1530113be6b7a7f1a21"
+checksum = "2b6e47d6bc66cd3cd42c8df8ff77a994a7743e889045c6b762a6dbc360ad8494"
+
+[[package]]
+name = "decodal-language-service"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f25e462dce7c86743bd229ba91b831daf7928d524de9cef4ef861257ca156aa8"
+dependencies = [
+ "decodal",
+]
+
+[[package]]
+name = "decodal-language-tools"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "08d8e3eb978cb1c2259df838ba2a8102bc45553d7b415216c80fc5b6a3f378c6"
+dependencies = [
+ "decodal",
+ "serde_json",
+ "wasm-bindgen",
+]
 
 [[package]]
 name = "deltae"
@@ -3748,6 +3793,17 @@ dependencies = [
  "serde_derive",
 ]
 
+[[package]]
+name = "serde-wasm-bindgen"
+version = "0.6.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8302e169f0eddcc139c70f139d19d6467353af16f9fce27e8c30158036a1e16b"
+dependencies = [
+ "js-sys",
+ "serde",
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "serde_cbor_2"
 version = "0.13.0"
@@ -6172,6 +6228,7 @@ dependencies = [
  "async-trait",
  "axum",
  "chrono",
+ "config-source",
  "flow",
  "futures",
  "manifest",

Cargo.toml

@@ -19,6 +19,8 @@ members = [
     "crates/tools",
     "crates/fs-operation",
     "crates/flow",
+    "crates/config-source",
+    "crates/config-source-wasm",
     "crates/workdir",
     "crates/tui",
     "crates/memory",
@@ -47,6 +49,8 @@ default-members = [
     "crates/tools",
     "crates/fs-operation",
     "crates/flow",
+    "crates/config-source",
+    "crates/config-source-wasm",
     "crates/workdir",
     "crates/tui",
     "crates/memory",
@@ -82,6 +86,7 @@ session-analytics = { path = "crates/session-analytics" }
 session-store = { path = "crates/session-store" }
 secrets = { path = "crates/secrets" }
 tools = { path = "crates/tools" }
+config-source = { path = "crates/config-source" }
 fs-operation = { path = "crates/fs-operation" }
 workdir = { path = "crates/workdir" }
 tui = { path = "crates/tui" }
@@ -93,7 +98,9 @@ yoi-workspace-server = { path = "crates/workspace-server" }
 async-trait = "0.1"
 axum = "0.8"
 base64 = "0.22.1"
-decodal = "0.1.1"
+decodal = "0.2.0"
+decodal-language-service = "0.2.0"
+decodal-language-tools = "0.2.0"
 fs4 = "0.13"
 futures = "0.3"
 libc = "0.2"

crates/config-source-wasm/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "config-source-wasm"
+version = "0.1.0"
+edition.workspace = true
+license.workspace = true
+publish = false
+
+[lib]
+crate-type = ["cdylib", "rlib"]
+
+[dependencies]
+config-source.workspace = true
+serde.workspace = true
+serde-wasm-bindgen = "0.6.5"
+wasm-bindgen = "0.2.105"

crates/config-source-wasm/src/lib.rs

@@ -0,0 +1,172 @@
+use config_source::{
+    ConfigTreeChange, ConfigTreeSnapshot, EvaluationResult, SnapshotEnvironment, ToolchainContract,
+    VirtualPath,
+};
+use serde_wasm_bindgen::{Serializer, from_value};
+use std::cell::RefCell;
+use wasm_bindgen::prelude::*;
+
+thread_local! {
+    static SESSION: RefCell<Option<ConfigTreeSnapshot>> = const { RefCell::new(None) };
+}
+
+#[wasm_bindgen]
+pub fn set_snapshot(snapshot: JsValue) -> Result<(), JsValue> {
+    let snapshot: ConfigTreeSnapshot = decode(snapshot)?;
+    SESSION.with(|session| session.replace(Some(snapshot)));
+    Ok(())
+}
+
+#[wasm_bindgen]
+pub fn apply_changes(changes: JsValue) -> Result<JsValue, JsValue> {
+    let changes: Vec<ConfigTreeChange> = decode(changes)?;
+    SESSION.with(|session| {
+        let mut session = session.borrow_mut();
+        let snapshot = session
+            .as_ref()
+            .ok_or_else(|| JsValue::from_str("config source snapshot is not initialized"))?
+            .apply(&changes)
+            .map_err(js_error)?;
+        *session = Some(snapshot.clone());
+        encode(snapshot)
+    })
+}
+
+#[wasm_bindgen]
+pub fn changes_between(base: JsValue, candidate: JsValue) -> Result<JsValue, JsValue> {
+    let base: ConfigTreeSnapshot = decode(base)?;
+    let candidate: ConfigTreeSnapshot = decode(candidate)?;
+    encode(base.changes_to(&candidate))
+}
+
+#[wasm_bindgen]
+pub fn evaluate_current(contract: JsValue) -> Result<JsValue, JsValue> {
+    let contract: ToolchainContract = decode(contract)?;
+    SESSION.with(|session| {
+        let session = session.borrow();
+        let snapshot = session
+            .as_ref()
+            .ok_or_else(|| JsValue::from_str("config source snapshot is not initialized"))?;
+        encode(
+            SnapshotEnvironment::new(snapshot.clone())
+                .evaluate_contract(&contract)
+                .map_err(|diagnostics| {
+                    encode(&diagnostics).unwrap_or_else(|_| JsValue::from_str("evaluation failed"))
+                })?,
+        )
+    })
+}
+
+#[derive(serde::Serialize)]
+struct WasmCompletionResult {
+    from: usize,
+    items: Vec<WasmCompletionItem>,
+}
+
+#[derive(serde::Serialize)]
+struct WasmCompletionItem {
+    label: String,
+    kind: String,
+    detail: Option<String>,
+    priority: i32,
+}
+
+#[wasm_bindgen]
+pub fn complete_current(
+    entrypoint: String,
+    source: String,
+    utf16_offset: usize,
+    explicit: bool,
+) -> Result<JsValue, JsValue> {
+    let entrypoint = VirtualPath::parse(entrypoint).map_err(js_error)?;
+    SESSION.with(|session| {
+        let session = session.borrow();
+        let snapshot = session
+            .as_ref()
+            .ok_or_else(|| JsValue::from_str("config source snapshot is not initialized"))?;
+        let utf8_byte_offset = utf16_to_utf8_offset(&source, utf16_offset)?;
+        let result = SnapshotEnvironment::new(snapshot.clone())
+            .complete(&entrypoint, &source, utf8_byte_offset, explicit)
+            .map_err(|error| JsValue::from_str(&format!("{error:?}")))?
+            .map(|result| WasmCompletionResult {
+                from: result.from,
+                items: result
+                    .items
+                    .into_iter()
+                    .map(|item| WasmCompletionItem {
+                        label: item.label,
+                        kind: format!("{:?}", item.kind).to_lowercase(),
+                        detail: item.detail,
+                        priority: item.priority,
+                    })
+                    .collect(),
+            });
+        encode(result)
+    })
+}
+
+#[wasm_bindgen]
+pub fn evaluate_snapshot(snapshot: JsValue, contract: JsValue) -> Result<JsValue, JsValue> {
+    let snapshot: ConfigTreeSnapshot = decode(snapshot)?;
+    let contract: ToolchainContract = decode(contract)?;
+    encode(
+        SnapshotEnvironment::new(snapshot)
+            .evaluate_contract(&contract)
+            .map_err(|diagnostics| {
+                encode(&diagnostics).unwrap_or_else(|_| JsValue::from_str("evaluation failed"))
+            })?,
+    )
+}
+
+#[wasm_bindgen]
+pub fn analyze_snapshot(
+    snapshot: JsValue,
+    entrypoint: String,
+    source_override: Option<String>,
+) -> Result<JsValue, JsValue> {
+    let snapshot: ConfigTreeSnapshot = decode(snapshot)?;
+    let entrypoint = VirtualPath::parse(entrypoint).map_err(js_error)?;
+    encode(SnapshotEnvironment::new(snapshot).analyze(&entrypoint, source_override.as_deref()))
+}
+
+#[wasm_bindgen]
+pub fn format_source(source: String) -> Result<String, JsValue> {
+    SnapshotEnvironment::new(ConfigTreeSnapshot::empty())
+        .format(&source)
+        .map_err(|error| JsValue::from_str(&error))
+}
+
+fn utf16_to_utf8_offset(source: &str, utf16_offset: usize) -> Result<usize, JsValue> {
+    let mut units = 0usize;
+    for (byte_offset, character) in source.char_indices() {
+        if units == utf16_offset {
+            return Ok(byte_offset);
+        }
+        units += character.len_utf16();
+        if units > utf16_offset {
+            return Err(JsValue::from_str("UTF-16 offset splits a surrogate pair"));
+        }
+    }
+    if units == utf16_offset {
+        Ok(source.len())
+    } else {
+        Err(JsValue::from_str("UTF-16 offset is outside the source"))
+    }
+}
+
+fn decode<T: serde::de::DeserializeOwned>(value: JsValue) -> Result<T, JsValue> {
+    from_value(value).map_err(|error| JsValue::from_str(&error.to_string()))
+}
+
+fn encode<T: serde::Serialize>(value: T) -> Result<JsValue, JsValue> {
+    value
+        .serialize(&Serializer::json_compatible())
+        .map_err(|error| JsValue::from_str(&error.to_string()))
+}
+
+fn js_error(error: impl std::fmt::Display) -> JsValue {
+    JsValue::from_str(&error.to_string())
+}
+
+#[allow(dead_code)]
+fn _assert_serializable(_: EvaluationResult) {}

crates/config-source/Cargo.toml

@@ -0,0 +1,19 @@
+[package]
+name = "config-source"
+version = "0.1.0"
+edition.workspace = true
+license.workspace = true
+publish = false
+
+[dependencies]
+decodal.workspace = true
+decodal-language-service.workspace = true
+decodal-language-tools.workspace = true
+serde = { workspace = true, features = ["derive"] }
+serde_json.workspace = true
+sha2.workspace = true
+thiserror.workspace = true
+ts-rs = "12.0.1"
+
+[dev-dependencies]
+pretty_assertions = "1"

crates/flow/src/definition.rs

@@ -2,7 +2,7 @@ use std::collections::{BTreeMap, BTreeSet, VecDeque};
 use std::fmt;
 use std::fmt::Write as _;
 
-use decodal::{Engine, LoadedSource, SourceLoader};
+use decodal::{Engine, ImportLoader, LoadedImport};
 use serde::{Deserialize, Serialize};
 use sha2::{Digest, Sha256};
 
@@ -527,12 +527,12 @@ fn content_digest(content: &str) -> String {
 
 struct RejectImports;
 
-impl SourceLoader for RejectImports {
+impl ImportLoader for RejectImports {
     fn load(
         &mut self,
         _current_key: Option<&str>,
         specifier: &str,
-    ) -> decodal::Result<LoadedSource> {
+    ) -> decodal::Result<LoadedImport> {
         Err(decodal::Diagnostic::new(
             decodal::DiagnosticKind::Import,
             decodal::Span::default(),

crates/worker-runtime/src/profile_archive.rs

@@ -1,4 +1,4 @@
-use decodal::{Engine, LoadedSource, SourceLoader};
+use decodal::{Engine, ImportLoader, LoadedImport};
 use manifest::{ProfileSource, WorkerManifest, resolve_profile_artifact_value};
 use serde::{Deserialize, Serialize};
 use sha2::{Digest, Sha256};
@@ -424,12 +424,12 @@ impl<'a> ArchiveSourceLoader<'a> {
     }
 }
 
-impl SourceLoader for ArchiveSourceLoader<'_> {
+impl ImportLoader for ArchiveSourceLoader<'_> {
     fn load(
         &mut self,
         current_key: Option<&str>,
         specifier: &str,
-    ) -> decodal::Result<LoadedSource> {
+    ) -> decodal::Result<LoadedImport> {
         let path =
             archive_import_map_lookup(&self.archive.manifest.imports, current_key, specifier)
                 .map_err(import_diagnostic)?;
@@ -453,11 +453,7 @@ impl SourceLoader for ArchiveSourceLoader<'_> {
                 format!("archive source missing: {path}"),
             )
         })?;
-        Ok(LoadedSource {
+        Ok(LoadedImport::source(path.clone(), path, source.clone()))
-            key: path.clone(),
-            name: path.clone(),
-            source: source.clone(),
-        })
     }
 }
 
@@ -746,7 +742,12 @@ mod tests {
         let loaded = loader
             .load(Some("profiles/main.dcdl"), "./shared.dcdl")
             .unwrap();
-        assert_eq!(loaded.key, "profiles/shared.dcdl");
+        match loaded {
+            LoadedImport::Source(source) => {
+                assert_eq!(source.key, "profiles/shared.dcdl");
+            }
+            LoadedImport::Value(_) => panic!("expected source import"),
+        }
     }
 
     #[test]

crates/workspace-server/Cargo.toml

@@ -19,6 +19,7 @@ async-trait.workspace = true
 axum = { workspace = true, features = ["ws"] }
 chrono = { version = "0.4", default-features = false, features = ["clock"] }
 futures.workspace = true
+config-source.workspace = true
 flow = { path = "../flow" }
 manifest.workspace = true
 protocol = { workspace = true }

crates/workspace-server/src/config_source.rs

@@ -0,0 +1,619 @@
+use chrono::{SecondsFormat, Utc};
+use config_source::{
+    ConfigContentType, ConfigEntry, ConfigTreeChange, ConfigTreeSnapshot, DECODAL_VERSION,
+    DEFAULT_IMPORT_POLICY_VERSION, DEFAULT_SCHEMA_VERSION, EvaluationResult, SnapshotEnvironment,
+    ToolchainContract, VirtualPath,
+};
+use rusqlite::{OptionalExtension, TransactionBehavior, params};
+use serde::{Deserialize, Serialize};
+
+use crate::{Error, Result, SqliteWorkspaceStore};
+
+pub const DEFAULT_CONFIG_ENTRYPOINT: &str = "workspace.dcdl";
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize, ts_rs::TS)]
+#[ts(export)]
+pub struct WorkspaceConfigState {
+    pub snapshot: ConfigTreeSnapshot,
+    pub contract: ToolchainContract,
+    pub projection_digest: String,
+}
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize, ts_rs::TS)]
+#[ts(export)]
+pub struct EvaluatedConfigCandidate {
+    #[ts(type = "number")]
+    pub base_revision: u64,
+    pub base_digest: String,
+    pub snapshot: ConfigTreeSnapshot,
+    pub contract: ToolchainContract,
+    pub evaluation: EvaluationResult,
+}
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize, ts_rs::TS)]
+#[ts(export)]
+pub struct ConfigCommitRequest {
+    #[ts(type = "number")]
+    pub base_revision: u64,
+    pub base_digest: String,
+    pub changes: Vec<ConfigTreeChange>,
+    pub entrypoints: Vec<VirtualPath>,
+    pub toolchain_fingerprint: String,
+}
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize, ts_rs::TS)]
+#[ts(export)]
+pub struct ConfigPreviewRequest {
+    pub changes: Vec<ConfigTreeChange>,
+    pub entrypoints: Vec<VirtualPath>,
+}
+
+impl SqliteWorkspaceStore {
+    pub fn load_workspace_config(
+        &self,
+        workspace_id: &str,
+    ) -> Result<Option<WorkspaceConfigState>> {
+        self.with_conn(|conn| load_state(conn, workspace_id))
+    }
+
+    pub fn load_workspace_config_revision(
+        &self,
+        workspace_id: &str,
+        revision: u64,
+    ) -> Result<Option<ConfigTreeSnapshot>> {
+        self.with_conn(|conn| {
+            let manifest = conn
+                .query_row(
+                    "SELECT tree_digest, manifest_json FROM workspace_config_tree_revisions WHERE workspace_id = ?1 AND revision = ?2",
+                    params![workspace_id, revision as i64],
+                    |row| Ok((row.get::<_, String>(0)?, row.get::<_, String>(1)?)),
+                )
+                .optional()?;
+            let Some((stored_digest, manifest_json)) = manifest else {
+                return Ok(None);
+            };
+            let entries: std::collections::BTreeMap<VirtualPath, ConfigEntry> =
+                serde_json::from_str(&manifest_json)
+                    .map_err(|error| Error::RegistryInconsistency(error.to_string()))?;
+            let snapshot = ConfigTreeSnapshot::from_entries(revision, entries.into_values())
+                .map_err(config_error)?;
+            if snapshot.digest != stored_digest {
+                return Err(Error::RegistryInconsistency(format!(
+                    "virtual config revision digest mismatch for Workspace {workspace_id} revision {revision}"
+                )));
+            }
+            Ok(Some(snapshot))
+        })
+    }
+
+    pub fn evaluate_workspace_config_candidate(
+        &self,
+        workspace_id: &str,
+        request: &ConfigCommitRequest,
+    ) -> Result<EvaluatedConfigCandidate> {
+        let current = self
+            .load_workspace_config(workspace_id)?
+            .unwrap_or_else(empty_state);
+        if current.snapshot.revision != request.base_revision
+            || current.snapshot.digest != request.base_digest
+        {
+            return Err(config_conflict(format!(
+                "base revision/digest mismatch; current revision is {}",
+                current.snapshot.revision
+            )));
+        }
+        let expected_contract = ToolchainContract::new(
+            DEFAULT_SCHEMA_VERSION,
+            request.entrypoints.clone(),
+            DEFAULT_IMPORT_POLICY_VERSION,
+        );
+        if expected_contract.fingerprint != request.toolchain_fingerprint {
+            return Err(config_conflict(format!(
+                "toolchain fingerprint mismatch; current fingerprint is {}",
+                expected_contract.fingerprint
+            )));
+        }
+        evaluate_candidate(current, &request.changes, request.entrypoints.clone())
+    }
+
+    pub fn preview_workspace_config(
+        &self,
+        workspace_id: &str,
+        request: &ConfigPreviewRequest,
+    ) -> Result<EvaluatedConfigCandidate> {
+        let current = self
+            .load_workspace_config(workspace_id)?
+            .unwrap_or_else(empty_state);
+        evaluate_candidate(current, &request.changes, request.entrypoints.clone())
+    }
+
+    pub fn commit_evaluated_workspace_config(
+        &self,
+        workspace_id: &str,
+        candidate: &EvaluatedConfigCandidate,
+    ) -> Result<WorkspaceConfigState> {
+        self.with_conn_mut(|conn| {
+            let tx = conn.transaction_with_behavior(TransactionBehavior::Immediate)?;
+            let workspace_exists: bool = tx.query_row(
+                "SELECT EXISTS(SELECT 1 FROM workspaces WHERE workspace_id = ?1)",
+                [workspace_id],
+                |row| row.get(0),
+            )?;
+            if !workspace_exists {
+                return Err(Error::WorkspaceIdMismatch);
+            }
+            let current = load_state(&tx, workspace_id)?.unwrap_or_else(empty_state);
+            if current.snapshot.revision != candidate.base_revision
+                || current.snapshot.digest != candidate.base_digest
+            {
+                return Err(config_conflict(format!(
+                    "base revision/digest mismatch; current revision is {}",
+                    current.snapshot.revision
+                )));
+            }
+            let next_revision = current.snapshot.revision + 1;
+            let mut snapshot = candidate.snapshot.clone();
+            snapshot.revision = next_revision;
+            let now = Utc::now().to_rfc3339_opts(SecondsFormat::Millis, true);
+            tx.execute(
+                r#"INSERT INTO workspace_config_trees (
+                    workspace_id, revision, tree_digest, schema_version, entrypoints_json,
+                    decodal_version, import_policy_version, toolchain_fingerprint,
+                    projection_digest, updated_at
+                ) VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8, ?9, ?10)
+                ON CONFLICT(workspace_id) DO UPDATE SET
+                    revision = excluded.revision,
+                    tree_digest = excluded.tree_digest,
+                    schema_version = excluded.schema_version,
+                    decodal_version = excluded.decodal_version,
+                    import_policy_version = excluded.import_policy_version,
+                    toolchain_fingerprint = excluded.toolchain_fingerprint,
+                    projection_digest = excluded.projection_digest,
+                    updated_at = excluded.updated_at"#,
+                params![
+                    workspace_id,
+                    next_revision as i64,
+                    snapshot.digest,
+                    candidate.contract.schema_version,
+                    serde_json::to_string(&candidate.contract.entrypoints)
+                        .map_err(|error| Error::Store(error.to_string()))?,
+                    candidate.contract.decodal_version,
+                    candidate.contract.import_policy_version,
+                    candidate.contract.fingerprint,
+                    candidate.evaluation.projection_digest,
+                    now,
+                ],
+            )?;
+            tx.execute(
+                "DELETE FROM workspace_config_entries WHERE workspace_id = ?1",
+                [workspace_id],
+            )?;
+            for entry in snapshot.entries.values() {
+                tx.execute(
+                    r#"INSERT INTO workspace_config_entries (
+                        workspace_id, path, content_type, content, content_digest
+                    ) VALUES (?1, ?2, ?3, ?4, ?5)"#,
+                    params![
+                        workspace_id,
+                        entry.path.as_str(),
+                        content_type_label(entry.content_type),
+                        entry.content,
+                        entry.content_digest,
+                    ],
+                )?;
+            }
+            let manifest_json = serde_json::to_string(&snapshot.entries)
+                .map_err(|error| Error::Store(error.to_string()))?;
+            tx.execute(
+                r#"INSERT INTO workspace_config_tree_revisions (
+                    workspace_id, revision, tree_digest, toolchain_fingerprint,
+                    projection_digest, manifest_json, created_at
+                ) VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7)"#,
+                params![
+                    workspace_id,
+                    next_revision as i64,
+                    snapshot.digest,
+                    candidate.contract.fingerprint,
+                    candidate.evaluation.projection_digest,
+                    manifest_json,
+                    now,
+                ],
+            )?;
+            tx.commit()?;
+            Ok(WorkspaceConfigState {
+                snapshot,
+                contract: candidate.contract.clone(),
+                projection_digest: candidate.evaluation.projection_digest.clone(),
+            })
+        })
+    }
+
+    pub fn evaluate_and_commit_workspace_config(
+        &self,
+        workspace_id: &str,
+        request: &ConfigCommitRequest,
+    ) -> Result<WorkspaceConfigState> {
+        let candidate = self.evaluate_workspace_config_candidate(workspace_id, request)?;
+        self.commit_evaluated_workspace_config(workspace_id, &candidate)
+    }
+}
+
+fn evaluate_candidate(
+    current: WorkspaceConfigState,
+    changes: &[ConfigTreeChange],
+    entrypoints: Vec<VirtualPath>,
+) -> Result<EvaluatedConfigCandidate> {
+    let snapshot = current.snapshot.apply(changes).map_err(config_error)?;
+    let contract = ToolchainContract::new(
+        DEFAULT_SCHEMA_VERSION,
+        entrypoints,
+        DEFAULT_IMPORT_POLICY_VERSION,
+    );
+    let evaluation = SnapshotEnvironment::new(snapshot.clone())
+        .evaluate_contract(&contract)
+        .map_err(|diagnostics| {
+            Error::InvalidInput(
+                serde_json::to_string(&diagnostics)
+                    .unwrap_or_else(|_| "virtual config evaluation failed".to_string()),
+            )
+        })?;
+    Ok(EvaluatedConfigCandidate {
+        base_revision: current.snapshot.revision,
+        base_digest: current.snapshot.digest,
+        snapshot,
+        contract,
+        evaluation,
+    })
+}
+
+fn load_state(
+    conn: &rusqlite::Connection,
+    workspace_id: &str,
+) -> Result<Option<WorkspaceConfigState>> {
+    let header = conn
+        .query_row(
+            r#"SELECT revision, tree_digest, schema_version, entrypoints_json,
+                      decodal_version, import_policy_version, toolchain_fingerprint, projection_digest
+               FROM workspace_config_trees WHERE workspace_id = ?1"#,
+            [workspace_id],
+            |row| {
+                Ok((
+                    row.get::<_, i64>(0)?,
+                    row.get::<_, String>(1)?,
+                    row.get::<_, u32>(2)?,
+                    row.get::<_, String>(3)?,
+                    row.get::<_, String>(4)?,
+                    row.get::<_, u32>(5)?,
+                    row.get::<_, String>(6)?,
+                    row.get::<_, String>(7)?,
+                ))
+            },
+        )
+        .optional()?;
+    let Some((
+        revision,
+        stored_digest,
+        schema_version,
+        entrypoints_json,
+        decodal_version,
+        import_policy_version,
+        fingerprint,
+        projection_digest,
+    )) = header
+    else {
+        return Ok(None);
+    };
+    let mut statement = conn.prepare(
+        r#"SELECT path, content_type, content, content_digest
+           FROM workspace_config_entries WHERE workspace_id = ?1 ORDER BY path"#,
+    )?;
+    let entries = statement
+        .query_map([workspace_id], |row| {
+            let path = row.get::<_, String>(0)?;
+            let content_type = row.get::<_, String>(1)?;
+            let content = row.get::<_, String>(2)?;
+            let stored_entry_digest = row.get::<_, String>(3)?;
+            Ok((path, content_type, content, stored_entry_digest))
+        })?
+        .collect::<std::result::Result<Vec<_>, _>>()?
+        .into_iter()
+        .map(|(path, content_type, content, stored_entry_digest)| {
+            let path = VirtualPath::parse(path).map_err(config_error)?;
+            let entry = ConfigEntry::new(path, parse_content_type(&content_type)?, content)
+                .map_err(config_error)?;
+            if entry.content_digest != stored_entry_digest {
+                return Err(Error::RegistryInconsistency(format!(
+                    "virtual config entry digest mismatch for {}",
+                    entry.path
+                )));
+            }
+            Ok(entry)
+        })
+        .collect::<Result<Vec<_>>>()?;
+    let snapshot =
+        ConfigTreeSnapshot::from_entries(revision as u64, entries).map_err(config_error)?;
+    if snapshot.digest != stored_digest {
+        return Err(Error::RegistryInconsistency(format!(
+            "virtual config tree digest mismatch for Workspace {workspace_id}"
+        )));
+    }
+    let entrypoints: Vec<VirtualPath> = serde_json::from_str(&entrypoints_json)
+        .map_err(|error| Error::RegistryInconsistency(error.to_string()))?;
+    let contract = ToolchainContract::new(schema_version, entrypoints, import_policy_version);
+    if decodal_version != DECODAL_VERSION || contract.fingerprint != fingerprint {
+        return Err(Error::RegistryInconsistency(format!(
+            "virtual config toolchain metadata mismatch for Workspace {workspace_id}"
+        )));
+    }
+    Ok(Some(WorkspaceConfigState {
+        snapshot,
+        contract,
+        projection_digest,
+    }))
+}
+
+fn empty_state() -> WorkspaceConfigState {
+    WorkspaceConfigState {
+        snapshot: ConfigTreeSnapshot::empty(),
+        contract: ToolchainContract::new(
+            DEFAULT_SCHEMA_VERSION,
+            Vec::new(),
+            DEFAULT_IMPORT_POLICY_VERSION,
+        ),
+        projection_digest: config_source::digest_bytes(b"[]"),
+    }
+}
+
+fn content_type_label(value: ConfigContentType) -> &'static str {
+    match value {
+        ConfigContentType::Decodal => "decodal",
+        ConfigContentType::Text => "text",
+    }
+}
+
+fn parse_content_type(value: &str) -> Result<ConfigContentType> {
+    match value {
+        "decodal" => Ok(ConfigContentType::Decodal),
+        "text" => Ok(ConfigContentType::Text),
+        _ => Err(Error::RegistryInconsistency(format!(
+            "unknown virtual config content type {value:?}"
+        ))),
+    }
+}
+
+fn config_error(error: impl std::fmt::Display) -> Error {
+    Error::InvalidInput(error.to_string())
+}
+
+fn config_conflict(message: impl Into<String>) -> Error {
+    Error::WorkspaceConfigConflict(message.into())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::{ControlPlaneStore, WorkspaceRecord};
+
+    fn workspace() -> WorkspaceRecord {
+        WorkspaceRecord {
+            workspace_id: "w-config".into(),
+            owner_account_id: None,
+            display_name: "Config".into(),
+            state: "active".into(),
+            created_at: "2026-08-13T00:00:00Z".into(),
+            updated_at: "2026-08-13T00:00:00Z".into(),
+        }
+    }
+
+    fn path(value: &str) -> VirtualPath {
+        VirtualPath::parse(value).unwrap()
+    }
+
+    #[tokio::test]
+    async fn invalid_candidate_is_never_persisted() {
+        let store = SqliteWorkspaceStore::in_memory().unwrap();
+        store.upsert_workspace(&workspace()).await.unwrap();
+        let current = ConfigTreeSnapshot::empty();
+        let error = store
+            .evaluate_and_commit_workspace_config(
+                "w-config",
+                &ConfigCommitRequest {
+                    base_revision: 0,
+                    base_digest: current.digest,
+                    changes: vec![ConfigTreeChange::Create {
+                        path: path(DEFAULT_CONFIG_ENTRYPOINT),
+                        content_type: ConfigContentType::Decodal,
+                        content: "{ broken = ; }".into(),
+                    }],
+                    entrypoints: vec![path(DEFAULT_CONFIG_ENTRYPOINT)],
+                    toolchain_fingerprint: ToolchainContract::new(
+                        DEFAULT_SCHEMA_VERSION,
+                        vec![path(DEFAULT_CONFIG_ENTRYPOINT)],
+                        DEFAULT_IMPORT_POLICY_VERSION,
+                    )
+                    .fingerprint,
+                },
+            )
+            .unwrap_err();
+        assert!(matches!(error, Error::InvalidInput(_)));
+        assert!(store.load_workspace_config("w-config").unwrap().is_none());
+    }
+
+    #[tokio::test]
+    async fn valid_candidate_commits_snapshot_revision_and_provenance_atomically() {
+        let store = SqliteWorkspaceStore::in_memory().unwrap();
+        store.upsert_workspace(&workspace()).await.unwrap();
+        let empty = ConfigTreeSnapshot::empty();
+        let committed = store
+            .evaluate_and_commit_workspace_config(
+                "w-config",
+                &ConfigCommitRequest {
+                    base_revision: 0,
+                    base_digest: empty.digest,
+                    changes: vec![ConfigTreeChange::Create {
+                        path: path(DEFAULT_CONFIG_ENTRYPOINT),
+                        content_type: ConfigContentType::Decodal,
+                        content: "{ answer = 42; }".into(),
+                    }],
+                    entrypoints: vec![path(DEFAULT_CONFIG_ENTRYPOINT)],
+                    toolchain_fingerprint: ToolchainContract::new(
+                        DEFAULT_SCHEMA_VERSION,
+                        vec![path(DEFAULT_CONFIG_ENTRYPOINT)],
+                        DEFAULT_IMPORT_POLICY_VERSION,
+                    )
+                    .fingerprint,
+                },
+            )
+            .unwrap();
+        assert_eq!(committed.snapshot.revision, 1);
+        assert_eq!(committed.contract.decodal_version, DECODAL_VERSION);
+        assert!(!committed.projection_digest.is_empty());
+        let reread = store.load_workspace_config("w-config").unwrap().unwrap();
+        assert_eq!(reread.snapshot, committed.snapshot);
+    }
+
+    #[tokio::test]
+    async fn stale_cas_cannot_overwrite_newer_tree() {
+        let store = SqliteWorkspaceStore::in_memory().unwrap();
+        store.upsert_workspace(&workspace()).await.unwrap();
+        let empty = ConfigTreeSnapshot::empty();
+        let request = ConfigCommitRequest {
+            base_revision: 0,
+            base_digest: empty.digest,
+            changes: vec![ConfigTreeChange::Create {
+                path: path(DEFAULT_CONFIG_ENTRYPOINT),
+                content_type: ConfigContentType::Decodal,
+                content: "{ answer = 42; }".into(),
+            }],
+            entrypoints: vec![path(DEFAULT_CONFIG_ENTRYPOINT)],
+            toolchain_fingerprint: ToolchainContract::new(
+                DEFAULT_SCHEMA_VERSION,
+                vec![path(DEFAULT_CONFIG_ENTRYPOINT)],
+                DEFAULT_IMPORT_POLICY_VERSION,
+            )
+            .fingerprint,
+        };
+        let candidate = store
+            .evaluate_workspace_config_candidate("w-config", &request)
+            .unwrap();
+        store
+            .commit_evaluated_workspace_config("w-config", &candidate)
+            .unwrap();
+        let error = store
+            .commit_evaluated_workspace_config("w-config", &candidate)
+            .unwrap_err();
+        assert!(matches!(error, Error::WorkspaceConfigConflict(_)));
+    }
+
+    #[tokio::test]
+    async fn committed_revision_remains_retrievable_after_later_commit() {
+        let store = SqliteWorkspaceStore::in_memory().unwrap();
+        store.upsert_workspace(&workspace()).await.unwrap();
+        let empty = ConfigTreeSnapshot::empty();
+        let contract = ToolchainContract::new(
+            DEFAULT_SCHEMA_VERSION,
+            vec![path(DEFAULT_CONFIG_ENTRYPOINT)],
+            DEFAULT_IMPORT_POLICY_VERSION,
+        );
+        let first = store
+            .evaluate_and_commit_workspace_config(
+                "w-config",
+                &ConfigCommitRequest {
+                    base_revision: 0,
+                    base_digest: empty.digest,
+                    changes: vec![ConfigTreeChange::Create {
+                        path: path(DEFAULT_CONFIG_ENTRYPOINT),
+                        content_type: ConfigContentType::Decodal,
+                        content: "{ answer = 1; }".into(),
+                    }],
+                    entrypoints: contract.entrypoints.clone(),
+                    toolchain_fingerprint: contract.fingerprint.clone(),
+                },
+            )
+            .unwrap();
+        let entry = first
+            .snapshot
+            .get(&path(DEFAULT_CONFIG_ENTRYPOINT))
+            .unwrap();
+        store
+            .evaluate_and_commit_workspace_config(
+                "w-config",
+                &ConfigCommitRequest {
+                    base_revision: first.snapshot.revision,
+                    base_digest: first.snapshot.digest.clone(),
+                    changes: vec![ConfigTreeChange::Update {
+                        path: path(DEFAULT_CONFIG_ENTRYPOINT),
+                        expected_digest: entry.content_digest.clone(),
+                        content: "{ answer = 2; }".into(),
+                    }],
+                    entrypoints: contract.entrypoints,
+                    toolchain_fingerprint: contract.fingerprint,
+                },
+            )
+            .unwrap();
+        let revision = store
+            .load_workspace_config_revision("w-config", 1)
+            .unwrap()
+            .unwrap();
+        assert_eq!(revision, first.snapshot);
+    }
+
+    #[tokio::test]
+    async fn commit_rejects_mismatched_toolchain_fingerprint() {
+        let store = SqliteWorkspaceStore::in_memory().unwrap();
+        store.upsert_workspace(&workspace()).await.unwrap();
+        let empty = ConfigTreeSnapshot::empty();
+        let error = store
+            .evaluate_and_commit_workspace_config(
+                "w-config",
+                &ConfigCommitRequest {
+                    base_revision: 0,
+                    base_digest: empty.digest,
+                    changes: vec![ConfigTreeChange::Create {
+                        path: path(DEFAULT_CONFIG_ENTRYPOINT),
+                        content_type: ConfigContentType::Decodal,
+                        content: "{ answer = 42; }".into(),
+                    }],
+                    entrypoints: vec![path(DEFAULT_CONFIG_ENTRYPOINT)],
+                    toolchain_fingerprint: "sha256:stale-toolchain".into(),
+                },
+            )
+            .unwrap_err();
+        assert!(matches!(error, Error::WorkspaceConfigConflict(_)));
+        assert!(store.load_workspace_config("w-config").unwrap().is_none());
+    }
+
+    #[test]
+    fn exports_typescript_transport_contract() {
+        use ts_rs::TS;
+        let output = std::path::Path::new(env!("CARGO_MANIFEST_DIR"))
+            .join("../../web/workspace/src/lib/workspace/config-source/generated/types");
+        let config = ts_rs::Config::default().with_out_dir(&output);
+        WorkspaceConfigState::export_all(&config).unwrap();
+        EvaluatedConfigCandidate::export_all(&config).unwrap();
+        ConfigCommitRequest::export_all(&config).unwrap();
+        ConfigPreviewRequest::export_all(&config).unwrap();
+    }
+
+    #[test]
+    fn migration_creates_config_authority_without_changing_applied_migrations() {
+        let store = SqliteWorkspaceStore::in_memory().unwrap();
+        store
+            .with_conn(|conn| {
+                for table in [
+                    "workspace_config_trees",
+                    "workspace_config_entries",
+                    "workspace_config_tree_revisions",
+                ] {
+                    let exists: bool = conn.query_row(
+                        "SELECT EXISTS(SELECT 1 FROM sqlite_master WHERE type = 'table' AND name = ?1)",
+                        [table],
+                        |row| row.get(0),
+                    )?;
+                    assert!(exists, "missing {table}");
+                }
+                Ok(())
+            })
+            .unwrap();
+    }
+}

crates/workspace-server/src/lib.rs

@@ -8,6 +8,7 @@ pub mod auth;
 pub mod authority;
 pub mod companion;
 pub mod config;
+pub mod config_source;
 pub mod hosts;
 pub mod identity;
 pub mod memory_backend;
@@ -106,6 +107,8 @@ pub enum Error {
     TicketAssignmentConflict(String),
     #[error("Workdir attachment conflict: {0}")]
     WorkdirAttachmentConflict(String),
+    #[error("Workspace config update conflict: {0}")]
+    WorkspaceConfigConflict(String),
     #[error("Registry inconsistency: {0}")]
     RegistryInconsistency(String),
     #[error("Worker source identity is invalid: {0}")]

crates/workspace-server/src/server.rs

@@ -12,6 +12,7 @@ use axum::response::{IntoResponse, Response};
 use axum::routing::{delete, get, patch, post, put};
 use axum::{Json, Router};
 use chrono::{Duration, SecondsFormat, Utc};
+use config_source::ConfigTreeSnapshot;
 use flow::{FlowSourceKind, FlowSourceResolveRequest, ResolvedFlowSource};
 use futures::{SinkExt, StreamExt};
 use memory::backend::{
@@ -61,6 +62,7 @@ use crate::companion::{
     CompanionStatusResponse, CompanionTranscriptProjection,
 };
 use crate::config::{BackendRuntimesConfigFile, RemoteRuntimeConfigFile, resolve_remote_runtime};
+use crate::config_source::{ConfigCommitRequest, ConfigPreviewRequest};
 use crate::hosts::{
     ConfigBundleCheckResult, ConfigBundleSyncResult, DiagnosticSeverity, EMBEDDED_RUNTIME_ID,
     EmbeddedWorkerRuntime, HostSummary, RemoteRuntimeConfig, RemoteWorkerRuntime,
@@ -252,6 +254,7 @@ const ORCHESTRATOR_ATTENTION_PROMPT: &str = include_str!(concat!(
 pub struct WorkspaceApi {
     pub(crate) config: ServerConfig,
     pub(crate) store: Arc<dyn ControlPlaneStore>,
+    config_store: Arc<crate::SqliteWorkspaceStore>,
     authority: SqliteWorkspaceAuthority,
     runtime: Arc<RuntimeRegistry>,
     companion: Arc<CompanionConsole>,
@@ -741,7 +744,11 @@ impl WorkspaceApi {
         let runtime = Arc::new(runtime);
         let companion = Arc::new(CompanionConsole::disabled());
         let observation_proxy = BackendObservationProxy::new(config.runtime_event_sources.clone());
+        let config_store = Arc::new(crate::SqliteWorkspaceStore::open(
+            config.database_path.clone(),
+        )?);
         let api = Self {
+            config_store,
             authority: SqliteWorkspaceAuthority::new(
                 config.database_path.clone(),
                 config.workspace_id.clone(),
@@ -1132,6 +1139,26 @@ pub fn build_router(api: WorkspaceApi) -> Router {
             "/api/w/{workspace_id}/settings/workspace",
             get(scoped_get_workspace_settings).put(scoped_update_workspace_settings),
         )
+        .route(
+            "/api/w/{workspace_id}/config/source-tree",
+            get(scoped_get_workspace_config_tree),
+        )
+        .route(
+            "/api/w/{workspace_id}/config/source-tree/preview",
+            post(scoped_preview_workspace_config_tree),
+        )
+        .route(
+            "/api/w/{workspace_id}/config/source-tree/commit",
+            post(scoped_commit_workspace_config_tree),
+        )
+        .route(
+            "/api/w/{workspace_id}/config/source-tree/revisions/{revision}",
+            get(scoped_get_workspace_config_revision),
+        )
+        .route(
+            "/api/w/{workspace_id}/config/source-tree/entries/{*path}",
+            get(scoped_get_workspace_config_entry),
+        )
         .route(
             "/api/w/{workspace_id}/settings/profiles",
             get(scoped_get_profile_settings).post(scoped_create_profile_source),
@@ -2418,6 +2445,113 @@ async fn scoped_update_workspace_settings(
     ))
 }
 
+#[derive(Debug, Deserialize)]
+struct WorkspaceConfigRevisionPath {
+    workspace_id: String,
+    revision: u64,
+}
+
+async fn scoped_get_workspace_config_revision(
+    State(api): State<WorkspaceApi>,
+    AxumPath(path): AxumPath<WorkspaceConfigRevisionPath>,
+) -> ApiResult<Json<ConfigTreeSnapshot>> {
+    validate_workspace_scope(&api, &path.workspace_id)?;
+    let snapshot = api
+        .config_store
+        .load_workspace_config_revision(&path.workspace_id, path.revision)?
+        .ok_or_else(|| ApiError::from(Error::InvalidRecordId(path.revision.to_string())))?;
+    Ok(Json(snapshot))
+}
+
+#[derive(Debug, Deserialize)]
+struct WorkspaceConfigEntryPath {
+    workspace_id: String,
+    path: String,
+}
+
+#[derive(Debug, Serialize)]
+struct WorkspaceConfigTreeResponse {
+    snapshot: ConfigTreeSnapshot,
+    contract: config_source::ToolchainContract,
+    projection_digest: String,
+}
+
+async fn scoped_get_workspace_config_tree(
+    State(api): State<WorkspaceApi>,
+    AxumPath(path): AxumPath<ScopedWorkspacePath>,
+) -> ApiResult<Json<WorkspaceConfigTreeResponse>> {
+    validate_workspace_scope(&api, &path.workspace_id)?;
+    let state = api
+        .config_store
+        .load_workspace_config(&path.workspace_id)?
+        .unwrap_or_else(|| crate::config_source::WorkspaceConfigState {
+            snapshot: ConfigTreeSnapshot::empty(),
+            contract: config_source::ToolchainContract::new(
+                config_source::DEFAULT_SCHEMA_VERSION,
+                Vec::new(),
+                config_source::DEFAULT_IMPORT_POLICY_VERSION,
+            ),
+            projection_digest: config_source::digest_bytes(b"[]"),
+        });
+    Ok(Json(WorkspaceConfigTreeResponse {
+        snapshot: state.snapshot,
+        contract: state.contract,
+        projection_digest: state.projection_digest,
+    }))
+}
+
+async fn scoped_get_workspace_config_entry(
+    State(api): State<WorkspaceApi>,
+    AxumPath(path): AxumPath<WorkspaceConfigEntryPath>,
+) -> ApiResult<Json<config_source::ConfigEntry>> {
+    validate_workspace_scope(&api, &path.workspace_id)?;
+    let virtual_path = config_source::VirtualPath::parse(&path.path)
+        .map_err(|error| ApiError::from(Error::InvalidInput(error.to_string())))?;
+    let state = api
+        .config_store
+        .load_workspace_config(&path.workspace_id)?
+        .ok_or_else(|| {
+            ApiError::from(Error::InvalidRecordId("virtual config source tree".into()))
+        })?;
+    let entry = state
+        .snapshot
+        .get(&virtual_path)
+        .cloned()
+        .ok_or_else(|| ApiError::from(Error::InvalidRecordId(path.path)))?;
+    Ok(Json(entry))
+}
+
+async fn scoped_preview_workspace_config_tree(
+    State(api): State<WorkspaceApi>,
+    AxumPath(path): AxumPath<ScopedWorkspacePath>,
+    Json(request): Json<ConfigPreviewRequest>,
+) -> ApiResult<Json<crate::config_source::EvaluatedConfigCandidate>> {
+    validate_workspace_scope(&api, &path.workspace_id)?;
+    Ok(Json(
+        api.config_store
+            .preview_workspace_config(&path.workspace_id, &request)?,
+    ))
+}
+
+async fn scoped_commit_workspace_config_tree(
+    State(api): State<WorkspaceApi>,
+    AxumPath(path): AxumPath<ScopedWorkspacePath>,
+    Json(request): Json<ConfigCommitRequest>,
+) -> ApiResult<(StatusCode, Json<WorkspaceConfigTreeResponse>)> {
+    validate_workspace_scope(&api, &path.workspace_id)?;
+    let state = api
+        .config_store
+        .evaluate_and_commit_workspace_config(&path.workspace_id, &request)?;
+    Ok((
+        StatusCode::CREATED,
+        Json(WorkspaceConfigTreeResponse {
+            snapshot: state.snapshot,
+            contract: state.contract,
+            projection_digest: state.projection_digest,
+        }),
+    ))
+}
+
 async fn scoped_get_profile_settings(
     State(api): State<WorkspaceApi>,
     AxumPath(path): AxumPath<ScopedWorkspacePath>,
@@ -11273,9 +11407,9 @@ impl IntoResponse for ApiError {
             Error::BrowserMergeConfirmationRequired | Error::BrowserReopenConfirmationRequired => {
                 StatusCode::FORBIDDEN
             }
-            Error::TicketAssignmentConflict(_) | Error::WorkdirAttachmentConflict(_) => {
+            Error::TicketAssignmentConflict(_)
-                StatusCode::CONFLICT
+            | Error::WorkdirAttachmentConflict(_)
-            }
+            | Error::WorkspaceConfigConflict(_) => StatusCode::CONFLICT,
             Error::WorkerSourceIdentity(_) | Error::InvalidInput(_) => StatusCode::BAD_REQUEST,
             Error::InvalidRuntimeIdentifier { .. } | Error::ReservedWorkerName(_) => {
                 StatusCode::BAD_REQUEST

crates/workspace-server/src/store.rs

@@ -166,6 +166,11 @@ const MIGRATIONS: &[Migration] = &[
         name: "create Worker mutation source proof replay guard",
         apply: create_worker_mutation_source_proof_replay_guard,
     },
+    Migration {
+        version: 30,
+        name: "create Workspace virtual config source authority",
+        apply: create_workspace_config_source_authority,
+    },
 ];
 
 struct Migration {
@@ -4527,6 +4532,49 @@ fn current_schema_version(conn: &Connection) -> Result<i64> {
     .map_err(Error::from)
 }
 
+fn create_workspace_config_source_authority(conn: &Connection) -> Result<()> {
+    conn.execute_batch(
+        r#"
+        CREATE TABLE workspace_config_trees (
+            workspace_id TEXT PRIMARY KEY,
+            revision INTEGER NOT NULL CHECK (revision >= 0),
+            tree_digest TEXT NOT NULL,
+            schema_version INTEGER NOT NULL,
+            entrypoints_json TEXT NOT NULL,
+            decodal_version TEXT NOT NULL,
+            import_policy_version INTEGER NOT NULL,
+            toolchain_fingerprint TEXT NOT NULL,
+            projection_digest TEXT NOT NULL,
+            updated_at TEXT NOT NULL,
+            FOREIGN KEY (workspace_id) REFERENCES workspaces(workspace_id) ON DELETE CASCADE
+        );
+        CREATE TABLE workspace_config_entries (
+            workspace_id TEXT NOT NULL,
+            path TEXT NOT NULL,
+            content_type TEXT NOT NULL,
+            content TEXT NOT NULL,
+            content_digest TEXT NOT NULL,
+            PRIMARY KEY (workspace_id, path),
+            FOREIGN KEY (workspace_id) REFERENCES workspace_config_trees(workspace_id) ON DELETE CASCADE
+        );
+        CREATE INDEX idx_workspace_config_entries_prefix
+            ON workspace_config_entries(workspace_id, path);
+        CREATE TABLE workspace_config_tree_revisions (
+            workspace_id TEXT NOT NULL,
+            revision INTEGER NOT NULL,
+            tree_digest TEXT NOT NULL,
+            toolchain_fingerprint TEXT NOT NULL,
+            projection_digest TEXT NOT NULL,
+            manifest_json TEXT NOT NULL,
+            created_at TEXT NOT NULL,
+            PRIMARY KEY (workspace_id, revision),
+            FOREIGN KEY (workspace_id) REFERENCES workspaces(workspace_id) ON DELETE CASCADE
+        );
+        "#,
+    )?;
+    Ok(())
+}
+
 fn create_worker_mutation_source_proof_replay_guard(conn: &Connection) -> Result<()> {
     conn.execute_batch(
         r#"
@@ -5133,7 +5181,7 @@ CREATE TABLE ticket_worker_links (ticket_id TEXT, worker_ref_key TEXT);
 
         apply_migrations(&conn).unwrap();
 
-        assert_eq!(current_schema_version(&conn).unwrap(), 29);
+        assert_eq!(current_schema_version(&conn).unwrap(), 30);
         assert!(table_exists(&conn, "worker_workdir_attachment_reservations").unwrap());
     }
 
@@ -5166,7 +5214,7 @@ CREATE TABLE flow_events (event_id TEXT PRIMARY KEY);
 
         apply_migrations(&conn).unwrap();
 
-        assert_eq!(current_schema_version(&conn).unwrap(), 29);
+        assert_eq!(current_schema_version(&conn).unwrap(), 30);
         assert!(table_exists(&conn, "flow_sources").unwrap());
         assert!(table_exists(&conn, "flow_source_revisions").unwrap());
         assert!(!table_exists(&conn, "flow_instances").unwrap());
@@ -5233,7 +5281,7 @@ INSERT INTO worker_workdir_attachment_reservations (
 
         apply_migrations(&conn).unwrap();
 
-        assert_eq!(current_schema_version(&conn).unwrap(), 29);
+        assert_eq!(current_schema_version(&conn).unwrap(), 30);
         let repositories_sql: String = conn
             .query_row(
                 "SELECT sql FROM sqlite_master WHERE type = 'table' AND name = 'repositories'",

web/workspace/deno.json

@@ -15,9 +15,10 @@
     "@sveltejs/adapter-static": "npm:@sveltejs/adapter-static@3.0.9",
     "@sveltejs/kit": "npm:@sveltejs/kit@2.49.4",
     "@sveltejs/vite-plugin-svelte": "npm:@sveltejs/vite-plugin-svelte@6.2.1",
-    "@codemirror/state": "npm:@codemirror/state@6.5.2",
+    "@codemirror/autocomplete": "npm:@codemirror/autocomplete@6.20.0",
-    "@codemirror/view": "npm:@codemirror/view@6.38.8",
+    "@codemirror/state": "npm:@codemirror/state@6.7.1",
-    "decodal-codemirror": "npm:decodal-codemirror@0.1.2",
+    "@codemirror/view": "npm:@codemirror/view@6.43.8",
+    "decodal-codemirror": "npm:decodal-codemirror@0.1.6",
     "clsx": "npm:clsx@2.1.1",
     "cookie": "npm:cookie@0.6.0",
     "devalue": "npm:devalue@5.6.4",

web/workspace/deno.lock

@@ -1,15 +1,18 @@
 {
   "version": "5",
   "specifiers": {
-    "npm:@codemirror/state@6.5.2": "6.5.2",
+    "jsr:@std/assert@*": "1.0.19",
-    "npm:@codemirror/view@6.38.8": "6.38.8",
+    "jsr:@std/internal@^1.0.12": "1.0.14",
+    "npm:@codemirror/autocomplete@6.20.0": "6.20.0",
+    "npm:@codemirror/state@6.7.1": "6.7.1",
+    "npm:@codemirror/view@6.43.8": "6.43.8",
     "npm:@fontsource/ibm-plex-mono@5.3.0": "5.3.0",
     "npm:@sveltejs/adapter-static@3.0.9": "3.0.9_@sveltejs+kit@2.49.4__@sveltejs+vite-plugin-svelte@6.2.1___svelte@5.45.6___vite@7.2.7__svelte@5.45.6__typescript@5.9.3__vite@7.2.7_@sveltejs+vite-plugin-svelte@6.2.1__svelte@5.45.6__vite@7.2.7_svelte@5.45.6_typescript@5.9.3_vite@7.2.7",
     "npm:@sveltejs/kit@2.49.4": "2.49.4_@sveltejs+vite-plugin-svelte@6.2.1__svelte@5.45.6__vite@7.2.7_svelte@5.45.6_typescript@5.9.3_vite@7.2.7",
     "npm:@sveltejs/vite-plugin-svelte@6.2.1": "6.2.1_svelte@5.45.6_vite@7.2.7",
     "npm:clsx@2.1.1": "2.1.1",
     "npm:cookie@0.6.0": "0.6.0",
-    "npm:decodal-codemirror@0.1.2": "0.1.2",
+    "npm:decodal-codemirror@0.1.6": "0.1.6_@codemirror+view@6.43.8",
     "npm:devalue@5.6.4": "5.6.4",
     "npm:gen-interface-jp@0.8.0": "0.8.0",
     "npm:set-cookie-parser@2.7.2": "2.7.2",
@@ -20,7 +23,27 @@
     "npm:typescript@5.9.3": "5.9.3",
     "npm:vite@7.2.7": "7.2.7"
   },
+  "jsr": {
+    "@std/assert@1.0.19": {
+      "integrity": "eaada96ee120cb980bc47e040f82814d786fe8162ecc53c91d8df60b8755991e",
+      "dependencies": [
+        "jsr:@std/internal"
+      ]
+    },
+    "@std/internal@1.0.14": {
+      "integrity": "291516b3d4c35024d6ffbc0a9df5bf4c64116e05b50012cf846710152d2ffdf7"
+    }
+  },
   "npm": {
+    "@codemirror/autocomplete@6.20.0": {
+      "integrity": "sha512-bOwvTOIJcG5FVo5gUUupiwYh8MioPLQ4UcqbcRf7UQ98X90tCa9E1kZ3Z7tqwpZxYyOvh1YTYbmZE9RTfTp5hg==",
+      "dependencies": [
+        "@codemirror/language",
+        "@codemirror/state",
+        "@codemirror/view",
+        "@lezer/common"
+      ]
+    },
     "@codemirror/language@6.12.4": {
       "integrity": "sha512-1q4PaT+o6PbgpkJt4Q8Fv5XJxTy4FUZ4MWETtyiDw3J0Pyr9E2vqcKL+k9wcvjNTIsauxvE7OfmWj3FRPHQ76A==",
       "dependencies": [
@@ -32,14 +55,14 @@
         "style-mod"
       ]
     },
-    "@codemirror/state@6.5.2": {
+    "@codemirror/state@6.7.1": {
-      "integrity": "sha512-FVqsPqtPWKVVL3dPSxy8wEF/ymIEuVzF1PK3VbUgrxXpJUSHQWWZz4JMToquRxnkw+36LTamCZG2iua2Ptq0fA==",
+      "integrity": "sha512-9QzNDgE4EYDnAHfrTlR2lwiPciiOymLtwKK+8yHQzCc7GXhAP9xdEbEJFy2IWB1j9UGUl9BsgMmTo/ImA02T7A==",
       "dependencies": [
         "@marijn/find-cluster-break"
       ]
     },
-    "@codemirror/view@6.38.8": {
+    "@codemirror/view@6.43.8": {
-      "integrity": "sha512-XcE9fcnkHCbWkjeKyi0lllwXmBLtyYb5dt89dJyx23I9+LSh5vZDIuk7OLG4VM1lgrXZQcY6cxyZyk5WVPRv/A==",
+      "integrity": "sha512-qtItTDssZ/5GFfi94hrILu9j/VUeFPDPkhovEfmWFj2ipTxnzPB8DdHgfbb8HYTzLTYhrndKmyQxXUz/PDLenw==",
       "dependencies": [
         "@codemirror/state",
         "crelt",
@@ -531,10 +554,11 @@
         "ms"
       ]
     },
-    "decodal-codemirror@0.1.2": {
+    "decodal-codemirror@0.1.6_@codemirror+view@6.43.8": {
-      "integrity": "sha512-VR+cFsBLPb9kZU3gJhElZck+IUVhOC1HoWgA8bxP1kxwn+eCZaeBHErHESlRZbsWvN2J5T8VKcDCtxLDYe9QyA==",
+      "integrity": "sha512-XTS5vAY+vTb/yEg5n+1yORtBPuhozG4KO0YGbYEFR8oZX0KghZuHyFEsq/CJMXF223YMC/FQt3SC19NVYGWKMw==",
       "dependencies": [
         "@codemirror/language",
+        "@codemirror/view",
         "@lezer/highlight",
         "@lezer/lr"
       ]
@@ -975,14 +999,15 @@
   },
   "workspace": {
     "dependencies": [
-      "npm:@codemirror/state@6.5.2",
+      "npm:@codemirror/autocomplete@6.20.0",
-      "npm:@codemirror/view@6.38.8",
+      "npm:@codemirror/state@6.7.1",
+      "npm:@codemirror/view@6.43.8",
       "npm:@sveltejs/adapter-static@3.0.9",
       "npm:@sveltejs/kit@2.49.4",
       "npm:@sveltejs/vite-plugin-svelte@6.2.1",
       "npm:clsx@2.1.1",
       "npm:cookie@0.6.0",
-      "npm:decodal-codemirror@0.1.2",
+      "npm:decodal-codemirror@0.1.6",
       "npm:devalue@5.6.4",
       "npm:set-cookie-parser@2.7.2",
       "npm:shiki@3.13.0",

web/workspace/src/lib/workspace/config-source/ConfigSourceEditor.svelte

@@ -0,0 +1,350 @@
+<script lang="ts">
+  import { onMount } from "svelte";
+  import DecodalSourceEditor from "$lib/workspace/settings/DecodalSourceEditor.svelte";
+  import {
+    commitConfigTree,
+    fetchConfigTree,
+    previewConfigTree,
+  } from "./api.ts";
+  import { ConfigSourceToolchain } from "./toolchain.ts";
+  import type {
+    ConfigDiagnostic,
+    ConfigTreeChange,
+    WorkspaceConfigTreeResponse,
+  } from "./types.ts";
+
+  let { workspaceId }: { workspaceId: string } = $props();
+  let treeState = $state<WorkspaceConfigTreeResponse | null>(null);
+  let selectedPath = $state("");
+  let source = $state("");
+  let newPath = $state("workspace.dcdl");
+  let diagnostics = $state<ConfigDiagnostic[]>([]);
+  let status = $state("Loading source tree…");
+  let busy = $state(false);
+  let draftChanges = $state<ConfigTreeChange[]>([]);
+  let baseRevision = $state(0);
+  let baseDigest = $state("");
+  let renamePath = $state("");
+  let baseSnapshot = $state<WorkspaceConfigTreeResponse["snapshot"] | null>(null);
+  let preflightDigest = $state("");
+  let conflict = $state(false);
+  let candidateContract = $state<WorkspaceConfigTreeResponse["contract"] | null>(null);
+  let toolchain: ConfigSourceToolchain | null = null;
+
+  const paths = $derived(
+    treeState ? Object.keys(treeState.snapshot.entries).toSorted() : [],
+  );
+  const selected = $derived(
+    treeState && selectedPath ? treeState.snapshot.entries[selectedPath] : undefined,
+  );
+  const dirty = $derived(draftChanges.length > 0 || (selected ? source !== selected.content : source.length > 0));
+  const commitReady = $derived(dirty && preflightDigest === treeState?.snapshot.digest);
+
+  onMount(() => {
+    toolchain = new ConfigSourceToolchain();
+    void reload();
+    return () => toolchain?.close();
+  });
+
+  async function reload() {
+    try {
+      treeState = await fetchConfigTree(workspaceId);
+      if (!selectedPath || !treeState.snapshot.entries[selectedPath]) {
+        selectedPath = Object.keys(treeState.snapshot.entries).toSorted()[0] ?? "";
+      }
+      source = selectedPath ? treeState.snapshot.entries[selectedPath].content : "";
+      baseSnapshot = structuredClone(treeState.snapshot);
+      baseRevision = treeState.snapshot.revision;
+      baseDigest = treeState.snapshot.digest;
+      await toolchain?.setSnapshot(treeState.snapshot);
+      draftChanges = [];
+      renamePath = selectedPath;
+      diagnostics = [];
+      conflict = false;
+      candidateContract = null;
+      status = treeState.snapshot.revision === 0
+        ? "No committed sources yet. Create workspace.dcdl to begin."
+        : `Revision ${treeState.snapshot.revision} · ${treeState.snapshot.digest.slice(0, 20)}…`;
+    } catch (error) {
+      status = String(error);
+    }
+  }
+
+  async function stageCurrent() {
+    const change = currentChange();
+    if (!change || !toolchain) return;
+    const candidate = await toolchain.applyChanges([change]);
+    if (treeState) treeState = { ...treeState, snapshot: candidate };
+    if (baseSnapshot) draftChanges = await toolchain.changesBetween(baseSnapshot, candidate);
+    preflightDigest = "";
+    candidateContract = null;
+    conflict = false;
+  }
+
+  async function select(path: string) {
+    await stageCurrent();
+    selectedPath = path;
+    source = treeState?.snapshot.entries[path]?.content ?? "";
+    renamePath = path;
+    diagnostics = [];
+  }
+
+  function currentChange(): ConfigTreeChange | null {
+    if (!treeState || !selectedPath) return null;
+    const entry = treeState.snapshot.entries[selectedPath];
+    if (!entry) {
+      return {
+        kind: "create",
+        path: selectedPath,
+        content_type: "decodal",
+        content: source,
+      };
+    }
+    if (source === entry.content) return null;
+    return {
+      kind: "update",
+      path: selectedPath,
+      expected_digest: entry.content_digest,
+      content: source,
+    };
+  }
+
+  function entrypoints(): string[] {
+    if (!treeState) return [];
+    const known = new Set(Object.keys(treeState.snapshot.entries));
+    const configured = treeState.contract.entrypoints.filter((path) => known.has(path));
+    if (configured.length > 0) return configured;
+    if (treeState.snapshot.entries["workspace.dcdl"] || selectedPath === "workspace.dcdl") {
+      return ["workspace.dcdl"];
+    }
+    return selectedPath ? [selectedPath] : [];
+  }
+
+  async function analyze() {
+    if (!toolchain || !treeState || !selectedPath) return;
+    diagnostics = await toolchain.analyze(selectedPath, source);
+    status = diagnostics.length === 0 ? "No diagnostics." : `${diagnostics.length} diagnostic(s).`;
+  }
+
+  async function format() {
+    if (!toolchain) return;
+    try {
+      source = await toolchain.format(source);
+      await analyze();
+    } catch (error) {
+      status = String(error);
+    }
+  }
+
+  async function preview() {
+    if (!treeState) return;
+    await stageCurrent();
+    if (draftChanges.length === 0) {
+      status = "No draft changes to preview.";
+      return;
+    }
+    busy = true;
+    try {
+      const candidate = await previewConfigTree(workspaceId, {
+        changes: draftChanges,
+        entrypoints: entrypoints(),
+      });
+      await toolchain?.evaluate(candidate.contract);
+      diagnostics = [];
+      candidateContract = candidate.contract;
+      preflightDigest = candidate.snapshot.digest;
+      status = `Preview valid · projection ${candidate.evaluation.projection_digest.slice(0, 20)}…`;
+    } catch (error) {
+      const message = String(error);
+      conflict = message.includes("conflict") || message.includes("base revision/digest mismatch");
+      status = conflict ? `${message} Reload the authoritative tree before editing again.` : message;
+    } finally {
+      busy = false;
+    }
+  }
+
+  async function commit() {
+    if (!treeState) return;
+    await stageCurrent();
+    if (draftChanges.length === 0) {
+      status = "No draft changes to commit.";
+      return;
+    }
+    if (preflightDigest !== treeState.snapshot.digest || !candidateContract) {
+      status = "Preview the complete candidate successfully before Commit.";
+      return;
+    }
+    busy = true;
+    try {
+      treeState = await commitConfigTree(workspaceId, {
+        base_revision: baseRevision,
+        base_digest: baseDigest,
+        changes: draftChanges,
+        entrypoints: candidateContract.entrypoints,
+        toolchain_fingerprint: candidateContract.fingerprint,
+      });
+      draftChanges = [];
+      preflightDigest = "";
+    candidateContract = null;
+    conflict = false;
+      baseSnapshot = structuredClone(treeState.snapshot);
+      baseRevision = treeState.snapshot.revision;
+      baseDigest = treeState.snapshot.digest;
+      await toolchain?.setSnapshot(treeState.snapshot);
+      source = treeState.snapshot.entries[selectedPath]?.content ?? "";
+      diagnostics = [];
+      status = `Committed revision ${treeState.snapshot.revision}.`;
+    } catch (error) {
+      const message = String(error);
+      conflict = message.includes("conflict") || message.includes("base revision/digest mismatch");
+      status = conflict ? `${message} Reload the authoritative tree before editing again.` : message;
+    } finally {
+      busy = false;
+    }
+  }
+
+  async function discardAndReload() {
+    draftChanges = [];
+    source = "";
+    await reload();
+  }
+
+  async function reloadAndReapply() {
+    if (!toolchain || !treeState) return;
+    const localChanges = [...draftChanges];
+    const remote = await fetchConfigTree(workspaceId);
+    baseSnapshot = structuredClone(remote.snapshot);
+    baseRevision = remote.snapshot.revision;
+    baseDigest = remote.snapshot.digest;
+    await toolchain.setSnapshot(remote.snapshot);
+    try {
+      const candidate = await toolchain.applyChanges(localChanges);
+      draftChanges = localChanges;
+      treeState = { ...remote, snapshot: candidate };
+      selectedPath = candidate.entries[selectedPath] ? selectedPath : Object.keys(candidate.entries).toSorted()[0] ?? "";
+      source = selectedPath ? candidate.entries[selectedPath].content : "";
+      conflict = false;
+      preflightDigest = "";
+      candidateContract = null;
+      status = "Local changes reapplied to the latest revision. Preview again before Commit.";
+    } catch (error) {
+      conflict = true;
+      status = `Local changes conflict with the latest revision: ${String(error)}. Discard local changes or resolve against a fresh reload.`;
+    }
+  }
+
+  function createEntry() {
+    const path = newPath.trim();
+    if (!path || treeState?.snapshot.entries[path]) return;
+    selectedPath = path;
+    source = "{}\n";
+    diagnostics = [];
+    status = `Drafting new source ${path}. It is not persisted until Commit succeeds.`;
+  }
+
+  async function deleteEntry() {
+    if (!treeState || !selected || !toolchain) return;
+    const change: ConfigTreeChange = {
+      kind: "delete",
+      path: selectedPath,
+      expected_digest: selected.content_digest,
+    };
+    const candidate = await toolchain.applyChanges([change]);
+    treeState = { ...treeState, snapshot: candidate };
+    if (baseSnapshot) draftChanges = await toolchain.changesBetween(baseSnapshot, candidate);
+    preflightDigest = "";
+    candidateContract = null;
+    conflict = false;
+    selectedPath = Object.keys(candidate.entries).toSorted()[0] ?? "";
+    source = selectedPath ? candidate.entries[selectedPath].content : "";
+    renamePath = selectedPath;
+    status = "Delete staged. Preview and Commit to persist the candidate tree.";
+  }
+
+  async function renameEntry() {
+    if (!treeState || !selected || !toolchain) return;
+    const to = renamePath.trim();
+    if (!to || to === selectedPath) return;
+    await stageCurrent();
+    const change: ConfigTreeChange = {
+      kind: "rename",
+      from: selectedPath,
+      to,
+      expected_digest: selected.content_digest,
+    };
+    const candidate = await toolchain.applyChanges([change]);
+    treeState = { ...treeState, snapshot: candidate };
+    if (baseSnapshot) draftChanges = await toolchain.changesBetween(baseSnapshot, candidate);
+    preflightDigest = "";
+    candidateContract = null;
+    conflict = false;
+    selectedPath = to;
+    source = candidate.entries[to]?.content ?? "";
+    status = `Rename to ${to} staged. Preview and Commit to persist.`;
+  }
+</script>
+
+<section class="config-source-shell" aria-label="Workspace configuration source tree">
+  <aside class="config-source-tree">
+    <div class="config-source-tree__header">
+      <strong>Source tree</strong>
+      <span>{paths.length}</span>
+    </div>
+    <nav aria-label="Virtual configuration paths">
+      {#each paths as path}
+        <button
+          type="button"
+          class:active={path === selectedPath}
+          onclick={() => select(path)}
+        >{path}</button>
+      {/each}
+    </nav>
+    <form class="config-source-create" onsubmit={(event) => { event.preventDefault(); createEntry(); }}>
+      <label for="new-config-path">New path</label>
+      <input id="new-config-path" bind:value={newPath} placeholder="workspace.dcdl" />
+      <button type="submit">Create draft</button>
+    </form>
+  </aside>
+
+  <div class="config-source-workbench">
+    <header class="config-source-workbench__header">
+      <div>
+        <span>Virtual path</span>
+        <strong>{selectedPath || "Select or create a source"}</strong>
+      </div>
+      <div class="config-source-actions">
+        <input aria-label="Rename path" bind:value={renamePath} disabled={!selected || busy} />
+        <button type="button" onclick={renameEntry} disabled={!selected || renamePath === selectedPath || busy}>Rename</button>
+        <button type="button" onclick={format} disabled={!selectedPath || busy}>Format</button>
+        <button type="button" onclick={analyze} disabled={!selectedPath || busy}>Analyze</button>
+        <button type="button" onclick={preview} disabled={!dirty || busy}>Preview</button>
+        <button class="primary" type="button" onclick={commit} disabled={!commitReady || busy}>Commit</button>
+        <button class="danger" type="button" onclick={deleteEntry} disabled={!selected || busy}>Delete</button>
+      </div>
+    </header>
+    <DecodalSourceEditor
+      value={source}
+      readonly={!selectedPath || busy}
+      onChange={(value) => source = value}
+      onComplete={(value, offset, explicit) => toolchain?.complete(selectedPath, value, offset, explicit) ?? Promise.resolve(null)}
+    />
+    <p class="config-source-status" aria-live="polite">{status}</p>
+    {#if conflict}
+      <div class="config-source-conflict" role="alert">
+        <button type="button" onclick={discardAndReload}>Discard local candidate and reload</button>
+        <button type="button" onclick={reloadAndReapply}>Reload and reapply local candidate</button>
+      </div>
+    {/if}
+    {#if diagnostics.length > 0}
+      <ol class="config-source-diagnostics">
+        {#each diagnostics as diagnostic}
+          <li>
+            <strong>{diagnostic.kind}</strong>
+            <span>{diagnostic.message}</span>
+            <small>bytes {diagnostic.span.start_byte}–{diagnostic.span.end_byte}</small>
+          </li>
+        {/each}
+      </ol>
+    {/if}
+  </div>
+</section>

web/workspace/src/lib/workspace/config-source/api.ts

@@ -0,0 +1,84 @@
+import type {
+  ConfigCommitRequest,
+  ConfigEntry,
+  ConfigPreviewRequest,
+  ConfigTreeSnapshot,
+  EvaluatedConfigCandidate,
+  WorkspaceConfigTreeResponse,
+} from "./types.ts";
+
+function sourceTreeUrl(workspaceId: string): string {
+  return `/api/w/${encodeURIComponent(workspaceId)}/config/source-tree`;
+}
+
+async function readJson<T>(response: Response): Promise<T> {
+  if (!response.ok) {
+    const body = await response.text();
+    throw new Error(body || `${response.status} ${response.statusText}`);
+  }
+  return await response.json() as T;
+}
+
+export async function fetchConfigTree(
+  workspaceId: string,
+  fetcher: typeof fetch = fetch,
+): Promise<WorkspaceConfigTreeResponse> {
+  return await readJson(
+    await fetcher(sourceTreeUrl(workspaceId), {
+      headers: { accept: "application/json" },
+    }),
+  );
+}
+
+export async function fetchConfigEntry(
+  workspaceId: string,
+  path: string,
+  fetcher: typeof fetch = fetch,
+): Promise<ConfigEntry> {
+  return await readJson(
+    await fetcher(
+      `${sourceTreeUrl(workspaceId)}/entries/${encodeURIComponent(path)}`,
+      { headers: { accept: "application/json" } },
+    ),
+  );
+}
+
+export async function fetchConfigRevision(
+  workspaceId: string,
+  revision: number,
+  fetcher: typeof fetch = fetch,
+): Promise<ConfigTreeSnapshot> {
+  return await readJson(
+    await fetcher(`${sourceTreeUrl(workspaceId)}/revisions/${revision}`, {
+      headers: { accept: "application/json" },
+    }),
+  );
+}
+
+export async function previewConfigTree(
+  workspaceId: string,
+  request: ConfigPreviewRequest,
+  fetcher: typeof fetch = fetch,
+): Promise<EvaluatedConfigCandidate> {
+  return await readJson(
+    await fetcher(`${sourceTreeUrl(workspaceId)}/preview`, {
+      method: "POST",
+      headers: { "content-type": "application/json" },
+      body: JSON.stringify(request),
+    }),
+  );
+}
+
+export async function commitConfigTree(
+  workspaceId: string,
+  request: ConfigCommitRequest,
+  fetcher: typeof fetch = fetch,
+): Promise<WorkspaceConfigTreeResponse> {
+  return await readJson(
+    await fetcher(`${sourceTreeUrl(workspaceId)}/commit`, {
+      method: "POST",
+      headers: { "content-type": "application/json" },
+      body: JSON.stringify(request),
+    }),
+  );
+}

web/workspace/src/lib/workspace/config-source/generated/config_source_wasm.d.ts

@@ -0,0 +1,65 @@
+/* tslint:disable */
+/* eslint-disable */
+
+export function analyze_snapshot(snapshot: any, entrypoint: string, source_override?: string | null): any;
+
+export function apply_changes(changes: any): any;
+
+export function changes_between(base: any, candidate: any): any;
+
+export function complete_current(entrypoint: string, source: string, utf16_offset: number, explicit: boolean): any;
+
+export function evaluate_current(contract: any): any;
+
+export function evaluate_snapshot(snapshot: any, contract: any): any;
+
+export function formatSource(source: string): string;
+
+export function format_source(source: string): string;
+
+export function set_snapshot(snapshot: any): void;
+
+export type InitInput = RequestInfo | URL | Response | BufferSource | WebAssembly.Module;
+
+export interface InitOutput {
+    readonly memory: WebAssembly.Memory;
+    readonly analyze_snapshot: (a: any, b: number, c: number, d: number, e: number) => [number, number, number];
+    readonly apply_changes: (a: any) => [number, number, number];
+    readonly changes_between: (a: any, b: any) => [number, number, number];
+    readonly complete_current: (a: number, b: number, c: number, d: number, e: number, f: number) => [number, number, number];
+    readonly evaluate_current: (a: any) => [number, number, number];
+    readonly evaluate_snapshot: (a: any, b: any) => [number, number, number];
+    readonly format_source: (a: number, b: number) => [number, number, number, number];
+    readonly set_snapshot: (a: any) => [number, number];
+    readonly formatSource: (a: number, b: number) => [number, number];
+    readonly __wbindgen_malloc: (a: number, b: number) => number;
+    readonly __wbindgen_realloc: (a: number, b: number, c: number, d: number) => number;
+    readonly __wbindgen_exn_store: (a: number) => void;
+    readonly __externref_table_alloc: () => number;
+    readonly __wbindgen_externrefs: WebAssembly.Table;
+    readonly __externref_table_dealloc: (a: number) => void;
+    readonly __wbindgen_free: (a: number, b: number, c: number) => void;
+    readonly __wbindgen_start: () => void;
+}
+
+export type SyncInitInput = BufferSource | WebAssembly.Module;
+
+/**
+ * Instantiates the given `module`, which can either be bytes or
+ * a precompiled `WebAssembly.Module`.
+ *
+ * @param {{ module: SyncInitInput }} module - Passing `SyncInitInput` directly is deprecated.
+ *
+ * @returns {InitOutput}
+ */
+export function initSync(module: { module: SyncInitInput } | SyncInitInput): InitOutput;
+
+/**
+ * If `module_or_path` is {RequestInfo} or {URL}, makes a request and
+ * for everything else, calls `WebAssembly.instantiate` directly.
+ *
+ * @param {{ module_or_path: InitInput | Promise<InitInput> }} module_or_path - Passing `InitInput` directly is deprecated.
+ *
+ * @returns {Promise<InitOutput>}
+ */
+export default function __wbg_init (module_or_path?: { module_or_path: InitInput | Promise<InitInput> } | InitInput | Promise<InitInput>): Promise<InitOutput>;

web/workspace/src/lib/workspace/config-source/generated/config_source_wasm.js

@@ -0,0 +1,658 @@
+/* @ts-self-types="./config_source_wasm.d.ts" */
+
+/**
+ * @param {any} snapshot
+ * @param {string} entrypoint
+ * @param {string | null} [source_override]
+ * @returns {any}
+ */
+export function analyze_snapshot(snapshot, entrypoint, source_override) {
+    const ptr0 = passStringToWasm0(entrypoint, wasm.__wbindgen_malloc, wasm.__wbindgen_realloc);
+    const len0 = WASM_VECTOR_LEN;
+    var ptr1 = isLikeNone(source_override) ? 0 : passStringToWasm0(source_override, wasm.__wbindgen_malloc, wasm.__wbindgen_realloc);
+    var len1 = WASM_VECTOR_LEN;
+    const ret = wasm.analyze_snapshot(snapshot, ptr0, len0, ptr1, len1);
+    if (ret[2]) {
+        throw takeFromExternrefTable0(ret[1]);
+    }
+    return takeFromExternrefTable0(ret[0]);
+}
+
+/**
+ * @param {any} changes
+ * @returns {any}
+ */
+export function apply_changes(changes) {
+    const ret = wasm.apply_changes(changes);
+    if (ret[2]) {
+        throw takeFromExternrefTable0(ret[1]);
+    }
+    return takeFromExternrefTable0(ret[0]);
+}
+
+/**
+ * @param {any} base
+ * @param {any} candidate
+ * @returns {any}
+ */
+export function changes_between(base, candidate) {
+    const ret = wasm.changes_between(base, candidate);
+    if (ret[2]) {
+        throw takeFromExternrefTable0(ret[1]);
+    }
+    return takeFromExternrefTable0(ret[0]);
+}
+
+/**
+ * @param {string} entrypoint
+ * @param {string} source
+ * @param {number} utf16_offset
+ * @param {boolean} explicit
+ * @returns {any}
+ */
+export function complete_current(entrypoint, source, utf16_offset, explicit) {
+    const ptr0 = passStringToWasm0(entrypoint, wasm.__wbindgen_malloc, wasm.__wbindgen_realloc);
+    const len0 = WASM_VECTOR_LEN;
+    const ptr1 = passStringToWasm0(source, wasm.__wbindgen_malloc, wasm.__wbindgen_realloc);
+    const len1 = WASM_VECTOR_LEN;
+    const ret = wasm.complete_current(ptr0, len0, ptr1, len1, utf16_offset, explicit);
+    if (ret[2]) {
+        throw takeFromExternrefTable0(ret[1]);
+    }
+    return takeFromExternrefTable0(ret[0]);
+}
+
+/**
+ * @param {any} contract
+ * @returns {any}
+ */
+export function evaluate_current(contract) {
+    const ret = wasm.evaluate_current(contract);
+    if (ret[2]) {
+        throw takeFromExternrefTable0(ret[1]);
+    }
+    return takeFromExternrefTable0(ret[0]);
+}
+
+/**
+ * @param {any} snapshot
+ * @param {any} contract
+ * @returns {any}
+ */
+export function evaluate_snapshot(snapshot, contract) {
+    const ret = wasm.evaluate_snapshot(snapshot, contract);
+    if (ret[2]) {
+        throw takeFromExternrefTable0(ret[1]);
+    }
+    return takeFromExternrefTable0(ret[0]);
+}
+
+/**
+ * @param {string} source
+ * @returns {string}
+ */
+export function formatSource(source) {
+    let deferred2_0;
+    let deferred2_1;
+    try {
+        const ptr0 = passStringToWasm0(source, wasm.__wbindgen_malloc, wasm.__wbindgen_realloc);
+        const len0 = WASM_VECTOR_LEN;
+        const ret = wasm.formatSource(ptr0, len0);
+        deferred2_0 = ret[0];
+        deferred2_1 = ret[1];
+        return getStringFromWasm0(ret[0], ret[1]);
+    } finally {
+        wasm.__wbindgen_free(deferred2_0, deferred2_1, 1);
+    }
+}
+
+/**
+ * @param {string} source
+ * @returns {string}
+ */
+export function format_source(source) {
+    let deferred3_0;
+    let deferred3_1;
+    try {
+        const ptr0 = passStringToWasm0(source, wasm.__wbindgen_malloc, wasm.__wbindgen_realloc);
+        const len0 = WASM_VECTOR_LEN;
+        const ret = wasm.format_source(ptr0, len0);
+        var ptr2 = ret[0];
+        var len2 = ret[1];
+        if (ret[3]) {
+            ptr2 = 0; len2 = 0;
+            throw takeFromExternrefTable0(ret[2]);
+        }
+        deferred3_0 = ptr2;
+        deferred3_1 = len2;
+        return getStringFromWasm0(ptr2, len2);
+    } finally {
+        wasm.__wbindgen_free(deferred3_0, deferred3_1, 1);
+    }
+}
+
+/**
+ * @param {any} snapshot
+ */
+export function set_snapshot(snapshot) {
+    const ret = wasm.set_snapshot(snapshot);
+    if (ret[1]) {
+        throw takeFromExternrefTable0(ret[0]);
+    }
+}
+
+function __wbg_get_imports() {
+    const import0 = {
+        __proto__: null,
+        __wbg_Error_2e59b1b37a9a34c3: function(arg0, arg1) {
+            const ret = Error(getStringFromWasm0(arg0, arg1));
+            return ret;
+        },
+        __wbg_Number_e6ffdb596c888833: function(arg0) {
+            const ret = Number(arg0);
+            return ret;
+        },
+        __wbg_String_8564e559799eccda: function(arg0, arg1) {
+            const ret = String(arg1);
+            const ptr1 = passStringToWasm0(ret, wasm.__wbindgen_malloc, wasm.__wbindgen_realloc);
+            const len1 = WASM_VECTOR_LEN;
+            getDataViewMemory0().setInt32(arg0 + 4 * 1, len1, true);
+            getDataViewMemory0().setInt32(arg0 + 4 * 0, ptr1, true);
+        },
+        __wbg___wbindgen_bigint_get_as_i64_2c5082002e4826e2: function(arg0, arg1) {
+            const v = arg1;
+            const ret = typeof(v) === 'bigint' ? v : undefined;
+            getDataViewMemory0().setBigInt64(arg0 + 8 * 1, isLikeNone(ret) ? BigInt(0) : ret, true);
+            getDataViewMemory0().setInt32(arg0 + 4 * 0, !isLikeNone(ret), true);
+        },
+        __wbg___wbindgen_boolean_get_a86c216575a75c30: function(arg0) {
+            const v = arg0;
+            const ret = typeof(v) === 'boolean' ? v : undefined;
+            return isLikeNone(ret) ? 0xFFFFFF : ret ? 1 : 0;
+        },
+        __wbg___wbindgen_debug_string_dd5d2d07ce9e6c57: function(arg0, arg1) {
+            const ret = debugString(arg1);
+            const ptr1 = passStringToWasm0(ret, wasm.__wbindgen_malloc, wasm.__wbindgen_realloc);
+            const len1 = WASM_VECTOR_LEN;
+            getDataViewMemory0().setInt32(arg0 + 4 * 1, len1, true);
+            getDataViewMemory0().setInt32(arg0 + 4 * 0, ptr1, true);
+        },
+        __wbg___wbindgen_in_4bd7a57e54337366: function(arg0, arg1) {
+            const ret = arg0 in arg1;
+            return ret;
+        },
+        __wbg___wbindgen_is_bigint_6c98f7e945dacdde: function(arg0) {
+            const ret = typeof(arg0) === 'bigint';
+            return ret;
+        },
+        __wbg___wbindgen_is_function_49868bde5eb1e745: function(arg0) {
+            const ret = typeof(arg0) === 'function';
+            return ret;
+        },
+        __wbg___wbindgen_is_object_40c5a80572e8f9d3: function(arg0) {
+            const val = arg0;
+            const ret = typeof(val) === 'object' && val !== null;
+            return ret;
+        },
+        __wbg___wbindgen_is_string_b29b5c5a8065ba1a: function(arg0) {
+            const ret = typeof(arg0) === 'string';
+            return ret;
+        },
+        __wbg___wbindgen_is_undefined_c0cca72b82b86f4d: function(arg0) {
+            const ret = arg0 === undefined;
+            return ret;
+        },
+        __wbg___wbindgen_jsval_eq_7d430e744a913d26: function(arg0, arg1) {
+            const ret = arg0 === arg1;
+            return ret;
+        },
+        __wbg___wbindgen_jsval_loose_eq_3a72ae764d46d944: function(arg0, arg1) {
+            const ret = arg0 == arg1;
+            return ret;
+        },
+        __wbg___wbindgen_number_get_7579aab02a8a620c: function(arg0, arg1) {
+            const obj = arg1;
+            const ret = typeof(obj) === 'number' ? obj : undefined;
+            getDataViewMemory0().setFloat64(arg0 + 8 * 1, isLikeNone(ret) ? 0 : ret, true);
+            getDataViewMemory0().setInt32(arg0 + 4 * 0, !isLikeNone(ret), true);
+        },
+        __wbg___wbindgen_string_get_914df97fcfa788f2: function(arg0, arg1) {
+            const obj = arg1;
+            const ret = typeof(obj) === 'string' ? obj : undefined;
+            var ptr1 = isLikeNone(ret) ? 0 : passStringToWasm0(ret, wasm.__wbindgen_malloc, wasm.__wbindgen_realloc);
+            var len1 = WASM_VECTOR_LEN;
+            getDataViewMemory0().setInt32(arg0 + 4 * 1, len1, true);
+            getDataViewMemory0().setInt32(arg0 + 4 * 0, ptr1, true);
+        },
+        __wbg___wbindgen_throw_81fc77679af83bc6: function(arg0, arg1) {
+            throw new Error(getStringFromWasm0(arg0, arg1));
+        },
+        __wbg_call_7f2987183bb62793: function() { return handleError(function (arg0, arg1) {
+            const ret = arg0.call(arg1);
+            return ret;
+        }, arguments); },
+        __wbg_done_547d467e97529006: function(arg0) {
+            const ret = arg0.done;
+            return ret;
+        },
+        __wbg_entries_616b1a459b85be0b: function(arg0) {
+            const ret = Object.entries(arg0);
+            return ret;
+        },
+        __wbg_get_4848e350b40afc16: function(arg0, arg1) {
+            const ret = arg0[arg1 >>> 0];
+            return ret;
+        },
+        __wbg_get_ed0642c4b9d31ddf: function() { return handleError(function (arg0, arg1) {
+            const ret = Reflect.get(arg0, arg1);
+            return ret;
+        }, arguments); },
+        __wbg_get_unchecked_7d7babe32e9e6a54: function(arg0, arg1) {
+            const ret = arg0[arg1 >>> 0];
+            return ret;
+        },
+        __wbg_get_with_ref_key_6412cf3094599694: function(arg0, arg1) {
+            const ret = arg0[arg1];
+            return ret;
+        },
+        __wbg_instanceof_ArrayBuffer_ff7c1337a5e3b33a: function(arg0) {
+            let result;
+            try {
+                result = arg0 instanceof ArrayBuffer;
+            } catch (_) {
+                result = false;
+            }
+            const ret = result;
+            return ret;
+        },
+        __wbg_instanceof_Map_a10a2795ef4bfe97: function(arg0) {
+            let result;
+            try {
+                result = arg0 instanceof Map;
+            } catch (_) {
+                result = false;
+            }
+            const ret = result;
+            return ret;
+        },
+        __wbg_instanceof_Uint8Array_4b8da683deb25d72: function(arg0) {
+            let result;
+            try {
+                result = arg0 instanceof Uint8Array;
+            } catch (_) {
+                result = false;
+            }
+            const ret = result;
+            return ret;
+        },
+        __wbg_isArray_db61795ad004c139: function(arg0) {
+            const ret = Array.isArray(arg0);
+            return ret;
+        },
+        __wbg_isSafeInteger_ea83862ba994770c: function(arg0) {
+            const ret = Number.isSafeInteger(arg0);
+            return ret;
+        },
+        __wbg_iterator_de403ef31815a3e6: function() {
+            const ret = Symbol.iterator;
+            return ret;
+        },
+        __wbg_length_0c32cb8543c8e4c8: function(arg0) {
+            const ret = arg0.length;
+            return ret;
+        },
+        __wbg_length_6e821edde497a532: function(arg0) {
+            const ret = arg0.length;
+            return ret;
+        },
+        __wbg_new_4f9fafbb3909af72: function() {
+            const ret = new Object();
+            return ret;
+        },
+        __wbg_new_99cabae501c0a8a0: function() {
+            const ret = new Map();
+            return ret;
+        },
+        __wbg_new_a560378ea1240b14: function(arg0) {
+            const ret = new Uint8Array(arg0);
+            return ret;
+        },
+        __wbg_new_f3c9df4f38f3f798: function() {
+            const ret = new Array();
+            return ret;
+        },
+        __wbg_next_01132ed6134b8ef5: function(arg0) {
+            const ret = arg0.next;
+            return ret;
+        },
+        __wbg_next_b3713ec761a9dbfd: function() { return handleError(function (arg0) {
+            const ret = arg0.next();
+            return ret;
+        }, arguments); },
+        __wbg_prototypesetcall_3e05eb9545565046: function(arg0, arg1, arg2) {
+            Uint8Array.prototype.set.call(getArrayU8FromWasm0(arg0, arg1), arg2);
+        },
+        __wbg_set_08463b1df38a7e29: function(arg0, arg1, arg2) {
+            const ret = arg0.set(arg1, arg2);
+            return ret;
+        },
+        __wbg_set_6be42768c690e380: function(arg0, arg1, arg2) {
+            arg0[arg1] = arg2;
+        },
+        __wbg_set_6c60b2e8ad0e9383: function(arg0, arg1, arg2) {
+            arg0[arg1 >>> 0] = arg2;
+        },
+        __wbg_value_7f6052747ccf940f: function(arg0) {
+            const ret = arg0.value;
+            return ret;
+        },
+        __wbindgen_cast_0000000000000001: function(arg0) {
+            // Cast intrinsic for `F64 -> Externref`.
+            const ret = arg0;
+            return ret;
+        },
+        __wbindgen_cast_0000000000000002: function(arg0) {
+            // Cast intrinsic for `I64 -> Externref`.
+            const ret = arg0;
+            return ret;
+        },
+        __wbindgen_cast_0000000000000003: function(arg0, arg1) {
+            // Cast intrinsic for `Ref(String) -> Externref`.
+            const ret = getStringFromWasm0(arg0, arg1);
+            return ret;
+        },
+        __wbindgen_cast_0000000000000004: function(arg0) {
+            // Cast intrinsic for `U64 -> Externref`.
+            const ret = BigInt.asUintN(64, arg0);
+            return ret;
+        },
+        __wbindgen_init_externref_table: function() {
+            const table = wasm.__wbindgen_externrefs;
+            const offset = table.grow(4);
+            table.set(0, undefined);
+            table.set(offset + 0, undefined);
+            table.set(offset + 1, null);
+            table.set(offset + 2, true);
+            table.set(offset + 3, false);
+        },
+    };
+    return {
+        __proto__: null,
+        "./config_source_wasm_bg.js": import0,
+    };
+}
+
+function addToExternrefTable0(obj) {
+    const idx = wasm.__externref_table_alloc();
+    wasm.__wbindgen_externrefs.set(idx, obj);
+    return idx;
+}
+
+function debugString(val) {
+    // primitive types
+    const type = typeof val;
+    if (type == 'number' || type == 'boolean' || val == null) {
+        return  `${val}`;
+    }
+    if (type == 'string') {
+        return `"${val}"`;
+    }
+    if (type == 'symbol') {
+        const description = val.description;
+        if (description == null) {
+            return 'Symbol';
+        } else {
+            return `Symbol(${description})`;
+        }
+    }
+    if (type == 'function') {
+        const name = val.name;
+        if (typeof name == 'string' && name.length > 0) {
+            return `Function(${name})`;
+        } else {
+            return 'Function';
+        }
+    }
+    // objects
+    if (Array.isArray(val)) {
+        const length = val.length;
+        let debug = '[';
+        if (length > 0) {
+            debug += debugString(val[0]);
+        }
+        for(let i = 1; i < length; i++) {
+            debug += ', ' + debugString(val[i]);
+        }
+        debug += ']';
+        return debug;
+    }
+    // Test for built-in
+    const builtInMatches = /\[object ([^\]]+)\]/.exec(toString.call(val));
+    let className;
+    if (builtInMatches && builtInMatches.length > 1) {
+        className = builtInMatches[1];
+    } else {
+        // Failed to match the standard '[object ClassName]'
+        return toString.call(val);
+    }
+    if (className == 'Object') {
+        // we're a user defined class or Object
+        // JSON.stringify avoids problems with cycles, and is generally much
+        // easier than looping through ownProperties of `val`.
+        try {
+            return 'Object(' + JSON.stringify(val) + ')';
+        } catch (_) {
+            return 'Object';
+        }
+    }
+    // errors
+    if (val instanceof Error) {
+        return `${val.name}: ${val.message}\n${val.stack}`;
+    }
+    // TODO we could test for more things here, like `Set`s and `Map`s.
+    return className;
+}
+
+function getArrayU8FromWasm0(ptr, len) {
+    ptr = ptr >>> 0;
+    return getUint8ArrayMemory0().subarray(ptr / 1, ptr / 1 + len);
+}
+
+let cachedDataViewMemory0 = null;
+function getDataViewMemory0() {
+    if (cachedDataViewMemory0 === null || cachedDataViewMemory0.buffer.detached === true || (cachedDataViewMemory0.buffer.detached === undefined && cachedDataViewMemory0.buffer !== wasm.memory.buffer)) {
+        cachedDataViewMemory0 = new DataView(wasm.memory.buffer);
+    }
+    return cachedDataViewMemory0;
+}
+
+function getStringFromWasm0(ptr, len) {
+    ptr = ptr >>> 0;
+    return decodeText(ptr, len);
+}
+
+let cachedUint8ArrayMemory0 = null;
+function getUint8ArrayMemory0() {
+    if (cachedUint8ArrayMemory0 === null || cachedUint8ArrayMemory0.byteLength === 0) {
+        cachedUint8ArrayMemory0 = new Uint8Array(wasm.memory.buffer);
+    }
+    return cachedUint8ArrayMemory0;
+}
+
+function handleError(f, args) {
+    try {
+        return f.apply(this, args);
+    } catch (e) {
+        const idx = addToExternrefTable0(e);
+        wasm.__wbindgen_exn_store(idx);
+    }
+}
+
+function isLikeNone(x) {
+    return x === undefined || x === null;
+}
+
+function passStringToWasm0(arg, malloc, realloc) {
+    if (realloc === undefined) {
+        const buf = cachedTextEncoder.encode(arg);
+        const ptr = malloc(buf.length, 1) >>> 0;
+        getUint8ArrayMemory0().subarray(ptr, ptr + buf.length).set(buf);
+        WASM_VECTOR_LEN = buf.length;
+        return ptr;
+    }
+
+    let len = arg.length;
+    let ptr = malloc(len, 1) >>> 0;
+
+    const mem = getUint8ArrayMemory0();
+
+    let offset = 0;
+
+    for (; offset < len; offset++) {
+        const code = arg.charCodeAt(offset);
+        if (code > 0x7F) break;
+        mem[ptr + offset] = code;
+    }
+    if (offset !== len) {
+        if (offset !== 0) {
+            arg = arg.slice(offset);
+        }
+        ptr = realloc(ptr, len, len = offset + arg.length * 3, 1) >>> 0;
+        const view = getUint8ArrayMemory0().subarray(ptr + offset, ptr + len);
+        const ret = cachedTextEncoder.encodeInto(arg, view);
+
+        offset += ret.written;
+        ptr = realloc(ptr, len, offset, 1) >>> 0;
+    }
+
+    WASM_VECTOR_LEN = offset;
+    return ptr;
+}
+
+function takeFromExternrefTable0(idx) {
+    const value = wasm.__wbindgen_externrefs.get(idx);
+    wasm.__externref_table_dealloc(idx);
+    return value;
+}
+
+let cachedTextDecoder = new TextDecoder('utf-8', { ignoreBOM: true, fatal: true });
+cachedTextDecoder.decode();
+const MAX_SAFARI_DECODE_BYTES = 2146435072;
+let numBytesDecoded = 0;
+function decodeText(ptr, len) {
+    numBytesDecoded += len;
+    if (numBytesDecoded >= MAX_SAFARI_DECODE_BYTES) {
+        cachedTextDecoder = new TextDecoder('utf-8', { ignoreBOM: true, fatal: true });
+        cachedTextDecoder.decode();
+        numBytesDecoded = len;
+    }
+    return cachedTextDecoder.decode(getUint8ArrayMemory0().subarray(ptr, ptr + len));
+}
+
+const cachedTextEncoder = new TextEncoder();
+
+if (!('encodeInto' in cachedTextEncoder)) {
+    cachedTextEncoder.encodeInto = function (arg, view) {
+        const buf = cachedTextEncoder.encode(arg);
+        view.set(buf);
+        return {
+            read: arg.length,
+            written: buf.length
+        };
+    };
+}
+
+let WASM_VECTOR_LEN = 0;
+
+let wasmModule, wasm;
+function __wbg_finalize_init(instance, module) {
+    wasm = instance.exports;
+    wasmModule = module;
+    cachedDataViewMemory0 = null;
+    cachedUint8ArrayMemory0 = null;
+    wasm.__wbindgen_start();
+    return wasm;
+}
+
+async function __wbg_load(module, imports) {
+    if (typeof Response === 'function' && module instanceof Response) {
+        if (typeof WebAssembly.instantiateStreaming === 'function') {
+            try {
+                return await WebAssembly.instantiateStreaming(module, imports);
+            } catch (e) {
+                const validResponse = module.ok && expectedResponseType(module.type);
+
+                if (validResponse && module.headers.get('Content-Type') !== 'application/wasm') {
+                    console.warn("`WebAssembly.instantiateStreaming` failed because your server does not serve Wasm with `application/wasm` MIME type. Falling back to `WebAssembly.instantiate` which is slower. Original error:\n", e);
+
+                } else { throw e; }
+            }
+        }
+
+        const bytes = await module.arrayBuffer();
+        return await WebAssembly.instantiate(bytes, imports);
+    } else {
+        const instance = await WebAssembly.instantiate(module, imports);
+
+        if (instance instanceof WebAssembly.Instance) {
+            return { instance, module };
+        } else {
+            return instance;
+        }
+    }
+
+    function expectedResponseType(type) {
+        switch (type) {
+            case 'basic': case 'cors': case 'default': return true;
+        }
+        return false;
+    }
+}
+
+function initSync(module) {
+    if (wasm !== undefined) return wasm;
+
+
+    if (module !== undefined) {
+        if (Object.getPrototypeOf(module) === Object.prototype) {
+            ({module} = module)
+        } else {
+            console.warn('using deprecated parameters for `initSync()`; pass a single object instead')
+        }
+    }
+
+    const imports = __wbg_get_imports();
+    if (!(module instanceof WebAssembly.Module)) {
+        module = new WebAssembly.Module(module);
+    }
+    const instance = new WebAssembly.Instance(module, imports);
+    return __wbg_finalize_init(instance, module);
+}
+
+async function __wbg_init(module_or_path) {
+    if (wasm !== undefined) return wasm;
+
+
+    if (module_or_path !== undefined) {
+        if (Object.getPrototypeOf(module_or_path) === Object.prototype) {
+            ({module_or_path} = module_or_path)
+        } else {
+            console.warn('using deprecated parameters for the initialization function; pass a single object instead')
+        }
+    }
+
+    if (module_or_path === undefined) {
+        module_or_path = new URL('config_source_wasm_bg.wasm', import.meta.url);
+    }
+    const imports = __wbg_get_imports();
+
+    if (typeof module_or_path === 'string' || (typeof Request === 'function' && module_or_path instanceof Request) || (typeof URL === 'function' && module_or_path instanceof URL)) {
+        module_or_path = fetch(module_or_path);
+    }
+
+    const { instance, module } = await __wbg_load(await module_or_path, imports);
+
+    return __wbg_finalize_init(instance, module);
+}
+
+export { initSync, __wbg_init as default };

web/workspace/src/lib/workspace/config-source/generated/config_source_wasm_bg.wasm.d.ts

@@ -0,0 +1,20 @@
+/* tslint:disable */
+/* eslint-disable */
+export const memory: WebAssembly.Memory;
+export const analyze_snapshot: (a: any, b: number, c: number, d: number, e: number) => [number, number, number];
+export const apply_changes: (a: any) => [number, number, number];
+export const changes_between: (a: any, b: any) => [number, number, number];
+export const complete_current: (a: number, b: number, c: number, d: number, e: number, f: number) => [number, number, number];
+export const evaluate_current: (a: any) => [number, number, number];
+export const evaluate_snapshot: (a: any, b: any) => [number, number, number];
+export const format_source: (a: number, b: number) => [number, number, number, number];
+export const set_snapshot: (a: any) => [number, number];
+export const formatSource: (a: number, b: number) => [number, number];
+export const __wbindgen_malloc: (a: number, b: number) => number;
+export const __wbindgen_realloc: (a: number, b: number, c: number, d: number) => number;
+export const __wbindgen_exn_store: (a: number) => void;
+export const __externref_table_alloc: () => number;
+export const __wbindgen_externrefs: WebAssembly.Table;
+export const __externref_table_dealloc: (a: number) => void;
+export const __wbindgen_free: (a: number, b: number, c: number) => void;
+export const __wbindgen_start: () => void;

web/workspace/src/lib/workspace/config-source/generated/types/ConfigCommitRequest.ts

@@ -0,0 +1,5 @@
+// This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
+import type { ConfigTreeChange } from "./ConfigTreeChange";
+import type { VirtualPath } from "./VirtualPath";
+
+export type ConfigCommitRequest = { base_revision: number, base_digest: string, changes: Array<ConfigTreeChange>, entrypoints: Array<VirtualPath>, toolchain_fingerprint: string, };

web/workspace/src/lib/workspace/config-source/generated/types/ConfigContentType.ts

@@ -0,0 +1,3 @@
+// This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
+
+export type ConfigContentType = "decodal" | "text";

web/workspace/src/lib/workspace/config-source/generated/types/ConfigDiagnostic.ts

@@ -0,0 +1,6 @@
+// This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
+import type { ConfigDiagnosticLabel } from "./ConfigDiagnosticLabel";
+import type { ConfigSpan } from "./ConfigSpan";
+import type { VirtualPath } from "./VirtualPath";
+
+export type ConfigDiagnostic = { path: VirtualPath, revision: number, tree_digest: string, kind: string, span: ConfigSpan, message: string, labels: Array<ConfigDiagnosticLabel>, notes: Array<string>, };

web/workspace/src/lib/workspace/config-source/generated/types/ConfigDiagnosticLabel.ts

@@ -0,0 +1,4 @@
+// This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
+import type { ConfigSpan } from "./ConfigSpan";
+
+export type ConfigDiagnosticLabel = { span: ConfigSpan, message: string, };

web/workspace/src/lib/workspace/config-source/generated/types/ConfigEntry.ts

@@ -0,0 +1,5 @@
+// This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
+import type { ConfigContentType } from "./ConfigContentType";
+import type { VirtualPath } from "./VirtualPath";
+
+export type ConfigEntry = { path: VirtualPath, content_type: ConfigContentType, content: string, content_digest: string, };

web/workspace/src/lib/workspace/config-source/generated/types/ConfigPreviewRequest.ts

@@ -0,0 +1,5 @@
+// This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
+import type { ConfigTreeChange } from "./ConfigTreeChange";
+import type { VirtualPath } from "./VirtualPath";
+
+export type ConfigPreviewRequest = { changes: Array<ConfigTreeChange>, entrypoints: Array<VirtualPath>, };

web/workspace/src/lib/workspace/config-source/generated/types/ConfigSpan.ts

@@ -0,0 +1,3 @@
+// This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
+
+export type ConfigSpan = { start_byte: number, end_byte: number, };

web/workspace/src/lib/workspace/config-source/generated/types/ConfigTreeChange.ts

@@ -0,0 +1,5 @@
+// This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
+import type { ConfigContentType } from "./ConfigContentType";
+import type { VirtualPath } from "./VirtualPath";
+
+export type ConfigTreeChange = { "kind": "create", path: VirtualPath, content_type: ConfigContentType, content: string, } | { "kind": "update", path: VirtualPath, expected_digest: string, content: string, } | { "kind": "rename", from: VirtualPath, to: VirtualPath, expected_digest: string, } | { "kind": "delete", path: VirtualPath, expected_digest: string, };

web/workspace/src/lib/workspace/config-source/generated/types/ConfigTreeSnapshot.ts

@@ -0,0 +1,5 @@
+// This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
+import type { ConfigEntry } from "./ConfigEntry";
+import type { VirtualPath } from "./VirtualPath";
+
+export type ConfigTreeSnapshot = { revision: number, digest: string, entries: { [key in VirtualPath]: ConfigEntry }, };

web/workspace/src/lib/workspace/config-source/generated/types/EvaluatedConfigCandidate.ts

@@ -0,0 +1,6 @@
+// This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
+import type { ConfigTreeSnapshot } from "./ConfigTreeSnapshot";
+import type { EvaluationResult } from "./EvaluationResult";
+import type { ToolchainContract } from "./ToolchainContract";
+
+export type EvaluatedConfigCandidate = { base_revision: number, base_digest: string, snapshot: ConfigTreeSnapshot, contract: ToolchainContract, evaluation: EvaluationResult, };

web/workspace/src/lib/workspace/config-source/generated/types/EvaluatedProjection.ts

@@ -0,0 +1,4 @@
+// This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
+import type { VirtualPath } from "./VirtualPath";
+
+export type EvaluatedProjection = { entrypoint: VirtualPath, data_json: unknown, projection_digest: string, };

web/workspace/src/lib/workspace/config-source/generated/types/EvaluationResult.ts

@@ -0,0 +1,4 @@
+// This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
+import type { EvaluatedProjection } from "./EvaluatedProjection";
+
+export type EvaluationResult = { projections: Array<EvaluatedProjection>, projection_digest: string, };

web/workspace/src/lib/workspace/config-source/generated/types/ToolchainContract.ts

@@ -0,0 +1,4 @@
+// This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
+import type { VirtualPath } from "./VirtualPath";
+
+export type ToolchainContract = { contract_version: number, decodal_version: string, schema_version: number, entrypoints: Array<VirtualPath>, import_policy_version: number, fingerprint: string, };

web/workspace/src/lib/workspace/config-source/generated/types/VirtualPath.ts

@@ -0,0 +1,3 @@
+// This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
+
+export type VirtualPath = string;

web/workspace/src/lib/workspace/config-source/generated/types/WorkspaceConfigState.ts

@@ -0,0 +1,5 @@
+// This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
+import type { ConfigTreeSnapshot } from "./ConfigTreeSnapshot";
+import type { ToolchainContract } from "./ToolchainContract";
+
+export type WorkspaceConfigState = { snapshot: ConfigTreeSnapshot, contract: ToolchainContract, projection_digest: string, };

web/workspace/src/lib/workspace/config-source/toolchain.ts

@@ -0,0 +1,62 @@
+import type { ConfigDiagnostic, ConfigTreeChange, ConfigTreeSnapshot, ToolchainContract } from "./types.ts";
+import type { ConfigSourceWorkerRequest, ConfigSourceWorkerResponse } from "./toolchain.worker.ts";
+
+type Command =
+  | Omit<Extract<ConfigSourceWorkerRequest, { kind: "set_snapshot" }>, "id">
+  | Omit<Extract<ConfigSourceWorkerRequest, { kind: "apply_changes" }>, "id">
+  | Omit<Extract<ConfigSourceWorkerRequest, { kind: "changes_between" }>, "id">
+  | Omit<Extract<ConfigSourceWorkerRequest, { kind: "analyze" }>, "id">
+  | Omit<Extract<ConfigSourceWorkerRequest, { kind: "evaluate" }>, "id">
+  | Omit<Extract<ConfigSourceWorkerRequest, { kind: "complete" }>, "id">
+  | Omit<Extract<ConfigSourceWorkerRequest, { kind: "format" }>, "id">;
+
+export class ConfigSourceToolchain {
+  #worker: Worker;
+  #nextId = 1;
+  #pending = new Map<number, { resolve: (value: unknown) => void; reject: (reason: unknown) => void }>();
+
+  constructor(worker = new Worker(new URL("./toolchain.worker.ts", import.meta.url), { type: "module" })) {
+    this.#worker = worker;
+    worker.addEventListener("message", (event: MessageEvent<ConfigSourceWorkerResponse>) => {
+      const pending = this.#pending.get(event.data.id);
+      if (!pending) return;
+      this.#pending.delete(event.data.id);
+      if (event.data.ok) pending.resolve(event.data.result);
+      else pending.reject(event.data.error);
+    });
+  }
+
+  setSnapshot(snapshot: ConfigTreeSnapshot): Promise<void> {
+    return this.#request({ kind: "set_snapshot", snapshot });
+  }
+  applyChanges(changes: ConfigTreeChange[]): Promise<ConfigTreeSnapshot> {
+    return this.#request({ kind: "apply_changes", changes });
+  }
+  changesBetween(base: ConfigTreeSnapshot, candidate: ConfigTreeSnapshot): Promise<ConfigTreeChange[]> {
+    return this.#request({ kind: "changes_between", base, candidate });
+  }
+  analyze(path: string, source?: string): Promise<ConfigDiagnostic[]> {
+    return this.#request({ kind: "analyze", path, source });
+  }
+  evaluate(contract: ToolchainContract) {
+    return this.#request({ kind: "evaluate", contract });
+  }
+  complete(path: string, source: string, utf16Offset: number, explicit = false): Promise<import("@codemirror/autocomplete").CompletionResult | null> {
+    return this.#request({ kind: "complete", path, source, utf16Offset, explicit });
+  }
+  format(source: string): Promise<string> {
+    return this.#request({ kind: "format", source });
+  }
+  close(): void {
+    this.#worker.terminate();
+    for (const pending of this.#pending.values()) pending.reject(new Error("config source toolchain was closed"));
+    this.#pending.clear();
+  }
+  #request<T>(request: Command): Promise<T> {
+    const id = this.#nextId++;
+    return new Promise<T>((resolve, reject) => {
+      this.#pending.set(id, { resolve: (value) => resolve(value as T), reject });
+      this.#worker.postMessage({ ...request, id });
+    });
+  }
+}

web/workspace/src/lib/workspace/config-source/toolchain.worker.ts

@@ -0,0 +1,64 @@
+import init, {
+  analyze_snapshot,
+  apply_changes,
+  changes_between,
+  complete_current,
+  evaluate_current,
+  format_source,
+  set_snapshot,
+} from "./generated/config_source_wasm.js";
+import type { ConfigTreeChange } from "./types.ts";
+
+export type ConfigSourceWorkerRequest =
+  | { id: number; kind: "set_snapshot"; snapshot: unknown }
+  | { id: number; kind: "apply_changes"; changes: ConfigTreeChange[] }
+  | { id: number; kind: "changes_between"; base: unknown; candidate: unknown }
+  | { id: number; kind: "analyze"; path: string; source?: string }
+  | { id: number; kind: "evaluate"; contract: unknown }
+  | { id: number; kind: "complete"; path: string; source: string; utf16Offset: number; explicit: boolean }
+  | { id: number; kind: "format"; source: string };
+
+export type ConfigSourceWorkerResponse =
+  | { id: number; ok: true; result: unknown }
+  | { id: number; ok: false; error: unknown };
+
+const ready = init();
+let snapshot: unknown = null;
+
+self.onmessage = async (event: MessageEvent<ConfigSourceWorkerRequest>): Promise<void> => {
+  const request = event.data;
+  try {
+    await ready;
+    let result: unknown;
+    switch (request.kind) {
+      case "set_snapshot":
+        snapshot = request.snapshot;
+        set_snapshot(request.snapshot);
+        result = null;
+        break;
+      case "apply_changes":
+        snapshot = apply_changes(request.changes);
+        result = snapshot;
+        break;
+      case "changes_between":
+        result = changes_between(request.base, request.candidate);
+        break;
+      case "analyze":
+        if (!snapshot) throw new Error("config source snapshot is not initialized");
+        result = analyze_snapshot(snapshot, request.path, request.source);
+        break;
+      case "evaluate":
+        result = evaluate_current(request.contract);
+        break;
+      case "complete":
+        result = complete_current(request.path, request.source, request.utf16Offset, request.explicit);
+        break;
+      case "format":
+        result = format_source(request.source);
+        break;
+    }
+    self.postMessage({ id: request.id, ok: true, result });
+  } catch (error) {
+    self.postMessage({ id: request.id, ok: false, error: error instanceof Error ? error.message : error });
+  }
+};

web/workspace/src/lib/workspace/config-source/types.ts

@@ -0,0 +1,16 @@
+// Core and HTTP DTOs are generated from Rust with ts-rs.
+export type { ConfigContentType } from "./generated/types/ConfigContentType.ts";
+export type { ConfigDiagnostic } from "./generated/types/ConfigDiagnostic.ts";
+export type { ConfigDiagnosticLabel } from "./generated/types/ConfigDiagnosticLabel.ts";
+export type { ConfigEntry } from "./generated/types/ConfigEntry.ts";
+export type { ConfigSpan } from "./generated/types/ConfigSpan.ts";
+export type { ConfigTreeChange } from "./generated/types/ConfigTreeChange.ts";
+export type { ConfigTreeSnapshot } from "./generated/types/ConfigTreeSnapshot.ts";
+export type { EvaluatedProjection } from "./generated/types/EvaluatedProjection.ts";
+export type { EvaluationResult } from "./generated/types/EvaluationResult.ts";
+export type { ToolchainContract } from "./generated/types/ToolchainContract.ts";
+export type { VirtualPath } from "./generated/types/VirtualPath.ts";
+export type { ConfigCommitRequest } from "./generated/types/ConfigCommitRequest.ts";
+export type { ConfigPreviewRequest } from "./generated/types/ConfigPreviewRequest.ts";
+export type { EvaluatedConfigCandidate } from "./generated/types/EvaluatedConfigCandidate.ts";
+export type { WorkspaceConfigState as WorkspaceConfigTreeResponse } from "./generated/types/WorkspaceConfigState.ts";

web/workspace/src/lib/workspace/settings/DecodalSourceEditor.svelte

@@ -1,5 +1,6 @@
 <script lang="ts">
   import { untrack } from 'svelte';
+  import { autocompletion, type CompletionContext, type CompletionResult } from '@codemirror/autocomplete';
   import { EditorState } from '@codemirror/state';
   import { EditorView, keymap, lineNumbers, highlightActiveLine, drawSelection } from '@codemirror/view';
   import { decodal } from 'decodal-codemirror';
@@ -9,11 +10,13 @@
     readonly = false,
     ariaLabel = 'Decodal source',
     onChange = (_value: string) => {},
+    onComplete = undefined,
   }: {
     value?: string;
     readonly?: boolean;
     ariaLabel?: string;
     onChange?: (value: string) => void;
+    onComplete?: (source: string, utf16Offset: number, explicit: boolean) => Promise<CompletionResult | null>;
   } = $props();
 
   let host = $state<HTMLDivElement | null>(null);
@@ -39,6 +42,7 @@
     const initialValue = untrack(() => value);
     const initialReadonly = untrack(() => readonly);
     const handleChange = untrack(() => onChange);
+    const handleComplete = untrack(() => onComplete);
     const editor = new EditorView({
       parent: host,
       state: EditorState.create({
@@ -48,6 +52,10 @@
           drawSelection(),
           highlightActiveLine(),
           decodal(),
+          ...(handleComplete ? [autocompletion({ override: [async (context: CompletionContext) => {
+            const doc = context.state.doc.toString();
+            return await handleComplete(doc, context.pos, context.explicit);
+          }] })] : []),
           keymap.of([]),
           EditorState.readOnly.of(initialReadonly),
           EditorView.editable.of(!initialReadonly),

web/workspace/src/lib/workspace/settings/model.ts

@@ -7,6 +7,7 @@ export type Diagnostic = {
 export type SettingsSectionId =
   | "runtime-connections"
   | "runtime-inventory"
+  | "configuration-sources"
   | "profile-sources"
   | "backend-config"
   | "workspace-identity";
@@ -98,6 +99,18 @@ export const SETTINGS_SECTIONS: readonly SettingsSection[] = [
       "Console routes may still target a Runtime handle directly, but Runtime discovery belongs under Settings.",
     ],
   },
+  {
+    id: "configuration-sources",
+    label: "Configuration Sources",
+    status: "editable",
+    summary:
+      "Edit the Server-owned virtual Decodal source tree through one native/WASM toolchain contract.",
+    bullets: [
+      "Virtual paths and imports resolve inside the committed Workspace tree, never from browser or Server host paths.",
+      "Browser analysis is advisory; Server evaluation is required before an atomic revision commit.",
+      "Profile, Skill, Prompt, and Plugin consumers remain on their existing authorities until their follow-up cutovers.",
+    ],
+  },
   {
     id: "profile-sources",
     label: "Profile Sources",
@@ -160,6 +173,8 @@ export function settingsSectionHref(id: SettingsSectionId): string {
       return `${SETTINGS_ROUTE}/runtime-connections`;
     case "runtime-inventory":
       return `${SETTINGS_ROUTE}/runtimes`;
+    case "configuration-sources":
+      return `${SETTINGS_ROUTE}/configuration`;
     case "profile-sources":
       return `${SETTINGS_ROUTE}/profiles`;
     case "workspace-identity":

web/workspace/src/lib/workspace/styles/settings.css

@@ -515,6 +515,174 @@
     font-weight: 800;
     text-transform: uppercase;
   }
+  .config-source-shell {
+    display: grid;
+    grid-template-columns: minmax(12rem, 18rem) minmax(0, 1fr);
+    min-height: 40rem;
+    overflow: hidden;
+    border: 1px solid var(--line);
+    border-radius: var(--radius-panel);
+    background: var(--bg-raised);
+  }
+  .config-source-tree {
+    display: grid;
+    grid-template-rows: auto minmax(0, 1fr) auto;
+    border-right: 1px solid var(--line);
+    background: var(--bg-subtle);
+  }
+  .config-source-tree__header,
+  .config-source-workbench__header {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    gap: var(--space-3);
+    padding: var(--space-3);
+    border-bottom: 1px solid var(--line);
+  }
+  .config-source-tree nav {
+    display: grid;
+    align-content: start;
+    overflow: auto;
+    padding: var(--space-2);
+  }
+  .config-source-tree nav button {
+    border: 0;
+    border-radius: 0.45rem;
+    background: transparent;
+    color: var(--text-muted);
+    padding: 0.45rem 0.55rem;
+    font: inherit;
+    font-family: var(--font-mono);
+    text-align: left;
+    cursor: pointer;
+  }
+  .config-source-tree nav button.active,
+  .config-source-tree nav button:hover {
+    background: var(--interactive-hover);
+    color: var(--text-strong);
+  }
+  .config-source-create {
+    display: grid;
+    gap: var(--space-2);
+    padding: var(--space-3);
+    border-top: 1px solid var(--line);
+  }
+  .config-source-create label,
+  .config-source-workbench__header span {
+    color: var(--text-muted);
+    font-size: 0.75rem;
+  }
+  .config-source-create input,
+  .config-source-actions input {
+    min-width: 0;
+    border: 1px solid var(--line);
+    border-radius: 0.45rem;
+    background: var(--bg-raised);
+    color: var(--text-strong);
+    padding: 0.45rem;
+    font: inherit;
+    font-family: var(--font-mono);
+  }
+  .config-source-create button,
+  .config-source-actions button {
+    border: 1px solid var(--line);
+    border-radius: 0.45rem;
+    background: var(--bg-subtle);
+    color: var(--text-strong);
+    padding: 0.4rem 0.6rem;
+    cursor: pointer;
+  }
+  .config-source-actions button.primary {
+    border-color: transparent;
+    background: var(--accent);
+    color: var(--bg);
+  }
+  .config-source-actions button.danger {
+    color: var(--danger);
+  }
+  .config-source-actions button:disabled {
+    cursor: not-allowed;
+    opacity: 0.45;
+  }
+  .config-source-workbench {
+    display: grid;
+    grid-template-rows: auto minmax(20rem, 1fr) auto auto;
+    min-width: 0;
+  }
+  .config-source-workbench__header > div:first-child {
+    display: grid;
+    min-width: 0;
+  }
+  .config-source-workbench__header strong {
+    overflow: hidden;
+    font-family: var(--font-mono);
+    text-overflow: ellipsis;
+    white-space: nowrap;
+  }
+  .config-source-actions {
+    display: flex;
+    flex-wrap: wrap;
+    gap: var(--space-2);
+  }
+  .config-source-status {
+    margin: 0;
+    padding: var(--space-2) var(--space-3);
+    border-top: 1px solid var(--line);
+    color: var(--text-muted);
+    font-size: 0.8rem;
+  }
+  .config-source-conflict {
+    display: flex;
+    flex-wrap: wrap;
+    gap: var(--space-2);
+    padding: var(--space-3);
+    border-top: 1px solid var(--danger);
+    background: color-mix(in srgb, var(--danger) 8%, transparent);
+  }
+  .config-source-conflict button {
+    border: 1px solid var(--danger);
+    border-radius: 0.45rem;
+    background: var(--bg-raised);
+    color: var(--danger);
+    padding: 0.4rem 0.6rem;
+    cursor: pointer;
+  }
+  .config-source-diagnostics {
+    display: grid;
+    gap: var(--space-2);
+    max-height: 12rem;
+    overflow: auto;
+    margin: 0;
+    padding: var(--space-3);
+    border-top: 1px solid var(--line);
+  }
+  .config-source-diagnostics li {
+    display: grid;
+    grid-template-columns: auto 1fr auto;
+    gap: var(--space-2);
+    color: var(--text-muted);
+  }
+  .config-source-diagnostics strong {
+    color: var(--danger);
+  }
+  @media (max-width: 48rem) {
+    .config-source-shell {
+      grid-template-columns: 1fr;
+    }
+    .config-source-tree {
+      grid-template-rows: auto auto auto;
+      border-right: 0;
+      border-bottom: 1px solid var(--line);
+    }
+    .config-source-tree nav {
+      max-height: 12rem;
+    }
+    .config-source-workbench__header {
+      align-items: stretch;
+      flex-direction: column;
+    }
+  }
+
   .status-message.error {
     color: var(--danger);
   }

web/workspace/src/routes/w/[workspaceId]/settings/configuration/+page.svelte

@@ -0,0 +1,27 @@
+<script lang="ts">
+  import ConfigSourceEditor from "$lib/workspace/config-source/ConfigSourceEditor.svelte";
+  import type { PageProps } from "./$types";
+
+  let { data }: PageProps = $props();
+  let workspaceId = $derived(data.workspace?.workspace_id ?? "");
+  let workspaceName = $derived(data.workspace?.display_name ?? "Workspace");
+</script>
+
+<svelte:head>
+  <title>Configuration | {workspaceName}</title>
+</svelte:head>
+
+<section class="settings-page">
+  <header class="page-header">
+    <div>
+      <p class="eyebrow">Workspace settings</p>
+      <h2>Configuration</h2>
+      <p>
+        Edit the Server-owned virtual Decodal source tree. Drafts stay in this browser;
+        the Server persists only a fully evaluated candidate.
+      </p>
+    </div>
+  </header>
+
+  <ConfigSourceEditor {workspaceId} />
+</section>

web/workspace/test/config-source/api.test.ts

@@ -0,0 +1,64 @@
+/// <reference lib="deno.ns" />
+
+import { assert, assertEquals } from "jsr:@std/assert";
+import {
+  commitConfigTree,
+  fetchConfigEntry,
+  fetchConfigRevision,
+  fetchConfigTree,
+  previewConfigTree,
+} from "../../src/lib/workspace/config-source/api.ts";
+
+function response(body: unknown, status = 200): Response {
+  return new Response(JSON.stringify(body), {
+    status,
+    headers: { "content-type": "application/json" },
+  });
+}
+
+Deno.test("config source API stays workspace-scoped and separates preview from commit", async () => {
+  const calls: Array<{ url: string; init?: RequestInit }> = [];
+  const fetcher = ((input: string | URL | Request, init?: RequestInit) => {
+    calls.push({ url: String(input), init });
+    return Promise.resolve(response({ ok: true }));
+  }) as typeof fetch;
+
+  await fetchConfigTree("w/one", fetcher);
+  await fetchConfigRevision("w/one", 7, fetcher);
+  await fetchConfigEntry("w/one", "profiles/main.dcdl", fetcher);
+  await previewConfigTree("w/one", { changes: [], entrypoints: [] }, fetcher);
+  await commitConfigTree("w/one", {
+    base_revision: 4,
+    base_digest: "sha256:base",
+    changes: [],
+    entrypoints: [],
+    toolchain_fingerprint: "sha256:toolchain",
+  }, fetcher);
+
+  assertEquals(calls.map((call) => call.url), [
+    "/api/w/w%2Fone/config/source-tree",
+    "/api/w/w%2Fone/config/source-tree/revisions/7",
+    "/api/w/w%2Fone/config/source-tree/entries/profiles%2Fmain.dcdl",
+    "/api/w/w%2Fone/config/source-tree/preview",
+    "/api/w/w%2Fone/config/source-tree/commit",
+  ]);
+  assertEquals(calls[3].init?.method, "POST");
+  assertEquals(calls[4].init?.method, "POST");
+  assert(
+    String(calls[4].init?.body).includes('"base_digest":"sha256:base"'),
+  );
+});
+
+Deno.test("config source API surfaces failed evaluation instead of treating it as a draft write", async () => {
+  const fetcher = (() =>
+    Promise.resolve(
+      new Response("structured diagnostics", { status: 422 }),
+    )) as typeof fetch;
+  let message = "";
+  try {
+    await previewConfigTree("w", { changes: [], entrypoints: [] }, fetcher);
+  } catch (error) {
+    message = String(error);
+  }
+  assert(message.includes("structured diagnostics"));
+});

web/workspace/test/config-source/wasm-parity.test.ts

@@ -0,0 +1,67 @@
+/// <reference lib="deno.ns" />
+
+import { assertEquals } from "jsr:@std/assert";
+// The generated wasm-bindgen loader is JavaScript with an adjacent declaration file.
+// @ts-expect-error Deno checks the generated JS implementation rather than its .d.ts.
+import init, {
+  analyze_snapshot,
+  evaluate_snapshot,
+} from "../../src/lib/workspace/config-source/generated/config_source_wasm.js";
+import type { ConfigTreeSnapshot, ToolchainContract } from "../../src/lib/workspace/config-source/types.ts";
+
+const bytes = await Deno.readFile(
+  new URL("../../src/lib/workspace/config-source/generated/config_source_wasm_bg.wasm", import.meta.url),
+);
+await init({ module_or_path: bytes });
+
+const snapshot: ConfigTreeSnapshot = {
+  revision: 4,
+  digest: "sha256:test-tree",
+  entries: {
+    "workspace.dcdl": {
+      path: "workspace.dcdl",
+      content_type: "decodal",
+      content: 'import "./lib/value.dcdl"',
+      content_digest: "sha256:root",
+    },
+    "lib/value.dcdl": {
+      path: "lib/value.dcdl",
+      content_type: "decodal",
+      content: "{ answer = 42; }",
+      content_digest: "sha256:value",
+    },
+  },
+};
+
+const contract: ToolchainContract = {
+  contract_version: 1,
+  decodal_version: "0.2.0",
+  schema_version: 1,
+  entrypoints: ["workspace.dcdl"],
+  import_policy_version: 1,
+  fingerprint: "sha256:test-contract",
+};
+
+Deno.test("generated WASM evaluates the same virtual import contract", () => {
+  const result = evaluate_snapshot(snapshot, contract) as {
+    projections: Array<{ data_json: { answer: number } }>;
+  };
+  assertEquals(result.projections[0].data_json, { answer: 42 });
+});
+
+Deno.test("generated WASM diagnostics carry snapshot provenance", () => {
+  const diagnostics = analyze_snapshot(
+    snapshot,
+    "workspace.dcdl",
+    "{ broken = ; }",
+  ) as Array<{
+    path: string;
+    revision: number;
+    tree_digest: string;
+    kind: string;
+  }>;
+  assertEquals(diagnostics[0].path, "workspace.dcdl");
+  assertEquals(diagnostics[0].revision, 4);
+  assertEquals(diagnostics[0].tree_digest, "sha256:test-tree");
+  assertEquals(diagnostics[0].kind, "syntax");
+});