feat: add web console commands

crates/manifest/src/profile.rs

@@ -970,6 +970,12 @@ fn builtin_default_profile_artifact() -> serde_json::Value {
         "model": { "ref": "codex-oauth/gpt-5.5" },
         "session": { "record_event_trace": true },
         "engine": { "reasoning": "high" },
+        "compaction": {
+            "kind": "tokens",
+            "threshold": 240000,
+            "request_threshold": 270000,
+            "worker_context_max_tokens": 100000
+        },
         "feature": {
             "task": { "enabled": true },
             "memory": { "enabled": true },
@@ -1441,6 +1447,22 @@ mod tests {
         assert!(companion.delegation_scope.allow.is_empty());
         assert_eq!(companion.model.ref_.as_deref(), Some("codex-oauth/gpt-5.5"));
         assert!(companion.web.is_some());
+        assert_eq!(
+            companion.compaction.as_ref().unwrap().threshold,
+            Some(240000)
+        );
+        assert_eq!(
+            companion.compaction.as_ref().unwrap().request_threshold,
+            Some(270000)
+        );
+        assert_eq!(
+            companion
+                .compaction
+                .as_ref()
+                .unwrap()
+                .worker_context_max_tokens,
+            100000
+        );
 
         let intake = resolve("intake");
         assert!(intake.feature.task.enabled);
@@ -1450,6 +1472,7 @@ mod tests {
         assert!(intake.delegation_scope.allow.is_empty());
         assert_eq!(intake.model.ref_.as_deref(), Some("codex-oauth/gpt-5.5"));
         assert!(intake.web.is_some());
+        assert!(intake.compaction.is_some());
         assert!(!intake.feature.ticket_orchestration.enabled);
 
         let orchestrator = resolve("orchestrator");
@@ -1464,6 +1487,7 @@ mod tests {
             Some("codex-oauth/gpt-5.5")
         );
         assert!(orchestrator.web.is_some());
+        assert!(orchestrator.compaction.is_some());
 
         let coder = resolve("coder");
         assert!(coder.feature.task.enabled);
@@ -1472,6 +1496,7 @@ mod tests {
         assert!(coder.delegation_scope.allow.is_empty());
         assert_eq!(coder.model.ref_.as_deref(), Some("codex-oauth/gpt-5.5"));
         assert!(coder.web.is_some());
+        assert!(coder.compaction.is_some());
 
         let reviewer = resolve("reviewer");
         assert!(reviewer.feature.task.enabled);
@@ -1481,6 +1506,7 @@ mod tests {
         assert!(reviewer.delegation_scope.allow.is_empty());
         assert_eq!(reviewer.model.ref_.as_deref(), Some("codex-oauth/gpt-5.5"));
         assert!(reviewer.web.is_some());
+        assert!(reviewer.compaction.is_some());
     }
 
     #[test]

crates/tui/src/app.rs

@@ -2082,6 +2082,11 @@ impl App {
                 let value = serde_json::to_value(&item).expect("SystemItem is Serialize");
                 self.apply_system_item(&value);
             }
+            session_store::LogEntry::Extension {
+                domain, payload, ..
+            } if domain == "yoi.compaction" => {
+                self.apply_compaction_extension(&payload);
+            }
             // Non-history-bearing variants don't affect the block view.
             _ => {}
         }
@@ -2092,6 +2097,58 @@ impl App {
     /// Kind-based routing replaces the old free-text `[Notification]` /
     /// `[File: …]` parsing path: each kind maps directly to a typed
     /// block (`Block::Notify`, `Block::WorkerEvent`, …).
+    fn apply_compaction_extension(&mut self, payload: &serde_json::Value) {
+        if payload.get("kind").and_then(|value| value.as_str()) != Some("compaction_block") {
+            return;
+        }
+        match payload.get("state").and_then(|value| value.as_str()) {
+            Some("running") => {
+                if self.last_streaming_compact_mut().is_none() {
+                    self.blocks.push(Block::Compact(CompactEvent::Streaming {
+                        started_at: Instant::now(),
+                    }));
+                }
+            }
+            Some("done") => {
+                let new_segment_id = payload
+                    .get("new_segment_id")
+                    .and_then(|value| value.as_str())
+                    .and_then(|value| value.parse::<uuid::Uuid>().ok())
+                    .unwrap_or_else(uuid::Uuid::nil);
+                if let Some(evt) = self.last_streaming_compact_mut() {
+                    *evt = CompactEvent::Done {
+                        new_segment_id,
+                        elapsed_secs: None,
+                    };
+                } else {
+                    self.blocks.push(Block::Compact(CompactEvent::Done {
+                        new_segment_id,
+                        elapsed_secs: None,
+                    }));
+                }
+            }
+            Some("failed") => {
+                let error = payload
+                    .get("error")
+                    .and_then(|value| value.as_str())
+                    .unwrap_or("compact failed")
+                    .to_string();
+                if let Some(evt) = self.last_streaming_compact_mut() {
+                    *evt = CompactEvent::Failed {
+                        error,
+                        elapsed_secs: None,
+                    };
+                } else {
+                    self.blocks.push(Block::Compact(CompactEvent::Failed {
+                        error,
+                        elapsed_secs: None,
+                    }));
+                }
+            }
+            _ => {}
+        }
+    }
+
     fn apply_system_item(&mut self, value: &serde_json::Value) {
         let Ok(item) = serde_json::from_value::<session_store::SystemItem>(value.clone()) else {
             // Unknown / forward-compat shape: fall back to rendering the

crates/worker-runtime/src/execution.rs

@@ -398,6 +398,15 @@ pub trait WorkerExecutionBackend: Send + Sync + 'static {
     fn worker_snapshot(&self, _handle: &WorkerExecutionHandle) -> Option<protocol::Event> {
         None
     }
+
+    fn worker_completions(
+        &self,
+        _handle: &WorkerExecutionHandle,
+        _kind: protocol::CompletionKind,
+        _prefix: &str,
+    ) -> Vec<protocol::CompletionEntry> {
+        Vec::new()
+    }
 }
 
 #[derive(Clone)]
@@ -485,6 +494,15 @@ impl WorkerExecutionBackendRef {
     ) -> Option<protocol::Event> {
         self.backend.worker_snapshot(handle)
     }
+
+    pub(crate) fn worker_completions(
+        &self,
+        handle: &WorkerExecutionHandle,
+        kind: protocol::CompletionKind,
+        prefix: &str,
+    ) -> Vec<protocol::CompletionEntry> {
+        self.backend.worker_completions(handle, kind, prefix)
+    }
 }
 
 impl fmt::Debug for WorkerExecutionBackendRef {

crates/worker-runtime/src/http_server.rs

@@ -146,6 +146,10 @@ pub fn runtime_http_router(runtime: Runtime, local_token: Option<String>) -> Rou
             get(get_worker).delete(delete_worker),
         )
         .route("/v1/workers/{worker_id}/input", post(send_worker_input))
+        .route(
+            "/v1/workers/{worker_id}/completions",
+            post(worker_completions),
+        )
         .route("/v1/workers/{worker_id}/stop", post(stop_worker))
         .route("/v1/workers/{worker_id}/cancel", post(cancel_worker));
 
@@ -228,6 +232,20 @@ pub struct RuntimeHttpWorkerInputResponse {
     pub ack: WorkerInteractionAck,
 }
 
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
+pub struct RuntimeHttpWorkerCompletionsRequest {
+    pub kind: protocol::CompletionKind,
+    #[serde(default)]
+    pub prefix: String,
+}
+
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
+pub struct RuntimeHttpWorkerCompletionsResponse {
+    pub kind: protocol::CompletionKind,
+    pub prefix: String,
+    pub entries: Vec<protocol::CompletionEntry>,
+}
+
 /// Worker lifecycle request body used by stop/cancel endpoints.
 #[derive(Clone, Debug, Default, PartialEq, Eq, Serialize, Deserialize)]
 pub struct RuntimeHttpWorkerLifecycleRequest {
@@ -678,6 +696,24 @@ async fn send_worker_input(
     Ok(Json(RuntimeHttpWorkerInputResponse { ack }))
 }
 
+async fn worker_completions(
+    State(state): State<RuntimeHttpState>,
+    Path(worker_id): Path<String>,
+    body: Result<Json<RuntimeHttpWorkerCompletionsRequest>, JsonRejection>,
+) -> RestResult<RuntimeHttpWorkerCompletionsResponse> {
+    let worker_ref = worker_ref_for(&state.runtime, worker_id)?;
+    let Json(request) = body.map_err(RuntimeHttpRestError::json_rejection)?;
+    let entries = state
+        .runtime
+        .worker_completions(&worker_ref, request.kind, &request.prefix)
+        .map_err(RuntimeHttpRestError::runtime)?;
+    Ok(Json(RuntimeHttpWorkerCompletionsResponse {
+        kind: request.kind,
+        prefix: request.prefix,
+        entries,
+    }))
+}
+
 async fn stop_worker(
     State(state): State<RuntimeHttpState>,
     Path(worker_id): Path<String>,

crates/worker-runtime/src/interaction.rs

@@ -1,5 +1,6 @@
 use crate::catalog::WorkerStatus;
 use crate::identity::WorkerRef;
+use protocol::Segment;
 use serde::{Deserialize, Serialize};
 
 /// Input kind accepted by the embedded interaction API.
@@ -8,6 +9,15 @@ use serde::{Deserialize, Serialize};
 pub enum WorkerInputKind {
     User,
     System,
+    Compact,
+    ListRewindTargets,
+    RegisterPeer,
+}
+
+impl WorkerInputKind {
+    pub fn is_empty_content_allowed(&self) -> bool {
+        matches!(self, Self::Compact | Self::ListRewindTargets)
+    }
 }
 
 /// Worker input request accepted by a Runtime Worker.
@@ -15,6 +25,8 @@ pub enum WorkerInputKind {
 pub struct WorkerInput {
     pub kind: WorkerInputKind,
     pub content: String,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub segments: Option<Vec<Segment>>,
 }
 
 impl WorkerInput {
@@ -22,6 +34,7 @@ impl WorkerInput {
         Self {
             kind: WorkerInputKind::User,
             content: content.into(),
+            segments: None,
         }
     }
 
@@ -29,6 +42,7 @@ impl WorkerInput {
         Self {
             kind: WorkerInputKind::System,
             content: content.into(),
+            segments: None,
         }
     }
 }

crates/worker-runtime/src/runtime.rs

@@ -537,6 +537,28 @@ impl Runtime {
         })
     }
 
+    /// Return live completion entries for the Worker composer.
+    pub fn worker_completions(
+        &self,
+        worker_ref: &WorkerRef,
+        kind: protocol::CompletionKind,
+        prefix: &str,
+    ) -> Result<Vec<protocol::CompletionEntry>, RuntimeError> {
+        let (backend, handle) = {
+            let state = self.lock()?;
+            state.ensure_worker_ref(worker_ref)?;
+            let worker = state.worker(worker_ref)?;
+            (
+                state.execution_backend.clone(),
+                worker.execution_handle.clone(),
+            )
+        };
+        let Some((backend, handle)) = backend.zip(handle) else {
+            return Ok(Vec::new());
+        };
+        Ok(backend.worker_completions(&handle, kind, prefix))
+    }
+
     fn commit_created_worker(
         &self,
         worker_ref: &WorkerRef,
@@ -1730,11 +1752,20 @@ fn validate_create_worker_request(request: &CreateWorkerRequest) -> Result<(), R
 }
 
 fn validate_worker_input(input: &WorkerInput) -> Result<(), RuntimeError> {
-    if input.content.trim().is_empty() {
+    if !input.kind.is_empty_content_allowed() && input.content.trim().is_empty() {
         return Err(RuntimeError::InvalidRequest(
             "worker input content must not be empty".to_string(),
         ));
     }
+    if input
+        .segments
+        .as_ref()
+        .is_some_and(|segments| segments.is_empty())
+    {
+        return Err(RuntimeError::InvalidRequest(
+            "worker input segments must not be empty".to_string(),
+        ));
+    }
     Ok(())
 }
 
@@ -1742,9 +1773,11 @@ fn validate_worker_input(input: &WorkerInput) -> Result<(), RuntimeError> {
 fn input_protocol_event(input: &WorkerInput) -> protocol::Event {
     match input.kind {
         WorkerInputKind::User => protocol::Event::UserMessage {
-            segments: vec![protocol::Segment::Text {
-                content: input.content.clone(),
-            }],
+            segments: input.segments.clone().unwrap_or_else(|| {
+                vec![protocol::Segment::Text {
+                    content: input.content.clone(),
+                }]
+            }),
         },
         WorkerInputKind::System => protocol::Event::SystemItem {
             item: serde_json::json!({
@@ -1752,6 +1785,15 @@ fn input_protocol_event(input: &WorkerInput) -> protocol::Event {
                 "content": input.content.clone(),
             }),
         },
+        WorkerInputKind::Compact
+        | WorkerInputKind::ListRewindTargets
+        | WorkerInputKind::RegisterPeer => protocol::Event::SystemItem {
+            item: serde_json::json!({
+                "kind": "embedded_worker_command_input",
+                "command": input.kind,
+                "content": input.content.clone(),
+            }),
+        },
     }
 }
 

crates/worker-runtime/src/worker_backend.rs

@@ -996,31 +996,38 @@ where
             );
         }
 
-        let WorkerInputKind::User = input.kind else {
-            busy.store(false, Ordering::SeqCst);
-            return WorkerExecutionResult::unsupported(
-                WorkerExecutionOperation::Input,
-                "runtime adapter currently dispatches user input only",
-            );
+        let method = match input.kind {
+            WorkerInputKind::User => Method::Run {
+                input: input
+                    .segments
+                    .unwrap_or_else(|| vec![Segment::text(input.content.trim().to_string())]),
+            },
+            WorkerInputKind::System => Method::Notify {
+                message: input.content,
+                auto_run: true,
+            },
+            WorkerInputKind::Compact => Method::Compact,
+            WorkerInputKind::ListRewindTargets => Method::ListRewindTargets,
+            WorkerInputKind::RegisterPeer => Method::RegisterPeer {
+                name: input.content.trim().to_string(),
+            },
         };
-        let content = input.content.trim().to_string();
-        if content.is_empty() {
-            busy.store(false, Ordering::SeqCst);
-            return WorkerExecutionResult::rejected(
-                WorkerExecutionOperation::Input,
-                "runtime adapter rejects empty user input",
-            );
-        }
+        let accepted_run_state = match method {
+            Method::Run { .. } | Method::Notify { .. } | Method::Compact => {
+                WorkerExecutionRunState::Busy
+            }
+            _ => WorkerExecutionRunState::Idle,
+        };
+        let accepted_is_idle = accepted_run_state == WorkerExecutionRunState::Idle;
 
         let result = self.send_method(
             WorkerExecutionOperation::Input,
             worker,
-            Method::Run {
-                input: vec![Segment::text(content)],
-            },
-            WorkerExecutionRunState::Busy,
+            method,
+            accepted_run_state,
         );
-        if result.outcome != crate::execution::WorkerExecutionOutcome::Accepted {
+        if accepted_is_idle || result.outcome != crate::execution::WorkerExecutionOutcome::Accepted
+        {
             busy.store(false, Ordering::SeqCst);
         }
         result
@@ -1093,6 +1100,24 @@ where
             .get(handle.worker_ref())
             .map(|execution| execution.handle.snapshot_event())
     }
+
+    fn worker_completions(
+        &self,
+        handle: &WorkerExecutionHandle,
+        kind: protocol::CompletionKind,
+        prefix: &str,
+    ) -> Vec<protocol::CompletionEntry> {
+        if handle.backend_id() != self.backend_id() {
+            return Vec::new();
+        }
+        let Ok(workers) = self.workers.lock() else {
+            return Vec::new();
+        };
+        workers
+            .get(handle.worker_ref())
+            .map(|execution| execution.handle.completion_entries(kind, prefix))
+            .unwrap_or_default()
+    }
 }
 
 #[cfg(test)]

crates/worker/src/controller.rs

@@ -91,6 +91,44 @@ impl WorkerHandle {
         (event, entry_rx)
     }
 
+    pub fn completion_entries(
+        &self,
+        kind: protocol::CompletionKind,
+        prefix: &str,
+    ) -> Vec<protocol::CompletionEntry> {
+        match kind {
+            protocol::CompletionKind::File => self
+                .shared_state
+                .fs_view()
+                .map(|view| view.list_file_completions(prefix))
+                .unwrap_or_default()
+                .into_iter()
+                .map(|c| protocol::CompletionEntry {
+                    value: c.path,
+                    is_dir: c.is_dir,
+                })
+                .collect(),
+            protocol::CompletionKind::Knowledge => self
+                .shared_state
+                .list_knowledge_completions(prefix)
+                .into_iter()
+                .map(|c| protocol::CompletionEntry {
+                    value: c.slug,
+                    is_dir: false,
+                })
+                .collect(),
+            protocol::CompletionKind::Workflow => self
+                .shared_state
+                .list_workflow_completions(prefix)
+                .into_iter()
+                .map(|c| protocol::CompletionEntry {
+                    value: c.slug,
+                    is_dir: false,
+                })
+                .collect(),
+        }
+    }
+
     /// Broadcast an event to all listeners (including socket clients).
     pub fn send_event(&self, event: Event) -> Result<usize, broadcast::error::SendError<Event>> {
         self.event_tx.send(event)

crates/worker/src/ipc/server.rs

@@ -165,37 +165,7 @@ async fn handle_connection(stream: tokio::net::UnixStream, handle: WorkerHandle)
             method = reader.next::<Method>() => {
                 match method {
                     Ok(Some(Method::ListCompletions { kind, prefix })) => {
-                        let entries = match kind {
-                            protocol::CompletionKind::File => handle
-                                .shared_state
-                                .fs_view()
-                                .map(|view| view.list_file_completions(&prefix))
-                                .unwrap_or_default()
-                                .into_iter()
-                                .map(|c| protocol::CompletionEntry {
-                                    value: c.path,
-                                    is_dir: c.is_dir,
-                                })
-                                .collect(),
-                            protocol::CompletionKind::Knowledge => handle
-                                .shared_state
-                                .list_knowledge_completions(&prefix)
-                                .into_iter()
-                                .map(|c| protocol::CompletionEntry {
-                                    value: c.slug,
-                                    is_dir: false,
-                                })
-                                .collect(),
-                            protocol::CompletionKind::Workflow => handle
-                                .shared_state
-                                .list_workflow_completions(&prefix)
-                                .into_iter()
-                                .map(|c| protocol::CompletionEntry {
-                                    value: c.slug,
-                                    is_dir: false,
-                                })
-                                .collect(),
-                        };
+                        let entries = handle.completion_entries(kind, &prefix);
                         if writer
                             .write(&Event::Completions { kind, entries })
                             .await

crates/worker/src/worker.rs

@@ -38,6 +38,9 @@ use crate::hook::{
     PreToolCall,
 };
 use crate::in_flight::InFlightEvents;
+
+const COMPACTION_EXTENSION_DOMAIN: &str = "yoi.compaction";
+const COMPACTION_BLOCK_ID: &str = "compact";
 use crate::ipc::alerter::Alerter;
 use crate::ipc::interceptor::WorkerInterceptor;
 use crate::ipc::notify_buffer::NotifyBuffer;
@@ -2309,6 +2312,55 @@ impl<C: LlmClient, St: Store> Worker<C, St> {
             .map_err(WorkerError::Engine)
     }
 
+    fn persist_compaction_block(
+        &mut self,
+        state: &str,
+        message: &str,
+        error: Option<&str>,
+        new_segment_id: Option<SegmentId>,
+    ) -> Result<(), WorkerError> {
+        let payload = serde_json::json!({
+            "kind": "compaction_block",
+            "schema_version": 1,
+            "block_id": COMPACTION_BLOCK_ID,
+            "state": state,
+            "message": message,
+            "error": error,
+            "new_segment_id": new_segment_id.map(|id| id.to_string()),
+        });
+        Ok(self.commit_entry(LogEntry::Extension {
+            ts: segment_log::now_millis(),
+            domain: COMPACTION_EXTENSION_DOMAIN.into(),
+            payload,
+        })?)
+    }
+
+    fn persist_and_send_compact_start(&mut self) -> Result<(), WorkerError> {
+        self.persist_compaction_block("running", "Compacting…", None, None)?;
+        self.send_event(Event::CompactStart);
+        Ok(())
+    }
+
+    fn persist_and_send_compact_done(
+        &mut self,
+        new_segment_id: SegmentId,
+    ) -> Result<(), WorkerError> {
+        self.persist_compaction_block("done", "Compacted.", None, Some(new_segment_id))?;
+        self.send_event(Event::CompactDone { new_segment_id });
+        Ok(())
+    }
+
+    fn persist_and_send_compact_failed(&mut self, error: String) -> Result<(), WorkerError> {
+        self.persist_compaction_block(
+            "failed",
+            &format!("Compact failed: {error}"),
+            Some(error.as_str()),
+            None,
+        )?;
+        self.send_event(Event::CompactFailed { error });
+        Ok(())
+    }
+
     /// Perform compaction after a `compact_needed` abort and resume execution.
     ///
     /// Uses `Box::pin` for the recursive `resume()` call to break the
@@ -2334,14 +2386,14 @@ impl<C: LlmClient, St: Store> Worker<C, St> {
                 .map(|s| s.retained_tokens())
                 .unwrap_or(manifest::defaults::COMPACT_RETAINED_TOKENS);
 
-            self.send_event(Event::CompactStart);
+            self.persist_and_send_compact_start()?;
             match self.compact(retained).await {
                 Ok(new_segment_id) => {
                     info!(
                         new_segment_id = %new_segment_id,
                         "Compaction succeeded, resuming execution"
                     );
-                    self.send_event(Event::CompactDone { new_segment_id });
+                    self.persist_and_send_compact_done(new_segment_id)?;
                     if let Some(ref state) = self.compact_state {
                         state.record_compact_success();
                     }
@@ -2349,9 +2401,7 @@ impl<C: LlmClient, St: Store> Worker<C, St> {
                 }
                 Err(e) => {
                     warn!(error = %e, "Compaction failed during run");
-                    self.send_event(Event::CompactFailed {
-                        error: e.to_string(),
-                    });
+                    self.persist_and_send_compact_failed(e.to_string())?;
                     self.alert(
                         AlertLevel::Error,
                         AlertSource::Compactor,
@@ -2384,21 +2434,45 @@ impl<C: LlmClient, St: Store> Worker<C, St> {
         }
 
         let retained = state.retained_tokens();
-        self.send_event(Event::CompactStart);
+        if let Err(err) = self.persist_and_send_compact_start() {
+            warn!(error = %err, "failed to persist proactive compact start");
+            self.alert(
+                AlertLevel::Warn,
+                AlertSource::Compactor,
+                format!("pre-run compaction not started: failed to persist status block: {err}"),
+            );
+            return;
+        }
         match self.compact(retained).await {
             Ok(new_segment_id) => {
                 info!(
                     new_segment_id = %new_segment_id,
                     "Proactive pre-run compaction succeeded"
                 );
-                self.send_event(Event::CompactDone { new_segment_id });
+                if let Err(err) = self.persist_and_send_compact_done(new_segment_id) {
+                    warn!(error = %err, "failed to persist proactive compact completion");
+                    self.alert(
+                        AlertLevel::Warn,
+                        AlertSource::Compactor,
+                        format!(
+                            "pre-run compaction completed but status block was not persisted: {err}"
+                        ),
+                    );
+                }
                 state.record_compact_success();
             }
             Err(e) => {
                 warn!(error = %e, "Proactive pre-run compaction failed");
-                self.send_event(Event::CompactFailed {
-                    error: e.to_string(),
-                });
+                if let Err(err) = self.persist_and_send_compact_failed(e.to_string()) {
+                    warn!(error = %err, "failed to persist proactive compact failure");
+                    self.alert(
+                        AlertLevel::Warn,
+                        AlertSource::Compactor,
+                        format!(
+                            "pre-run compaction failed and status block was not persisted: {err}"
+                        ),
+                    );
+                }
                 self.alert(
                     AlertLevel::Warn,
                     AlertSource::Compactor,
@@ -2456,11 +2530,11 @@ impl<C: LlmClient, St: Store> Worker<C, St> {
         }
 
         self.join_memory_task().await;
-        self.send_event(Event::CompactStart);
+        self.persist_and_send_compact_start()?;
         match self.compact(retained).await {
             Ok(new_segment_id) => {
                 info!(new_segment_id = %new_segment_id, "Manual compaction succeeded");
-                self.send_event(Event::CompactDone { new_segment_id });
+                self.persist_and_send_compact_done(new_segment_id)?;
                 if let Some(ref state) = state {
                     state.record_compact_success();
                 }
@@ -2468,9 +2542,7 @@ impl<C: LlmClient, St: Store> Worker<C, St> {
             }
             Err(e) => {
                 warn!(error = %e, "Manual compaction failed");
-                self.send_event(Event::CompactFailed {
-                    error: e.to_string(),
-                });
+                self.persist_and_send_compact_failed(e.to_string())?;
                 self.alert(
                     AlertLevel::Error,
                     AlertSource::Compactor,

crates/workspace-server/src/hosts.rs

@@ -31,7 +31,8 @@ use worker_runtime::execution::{
 use worker_runtime::fs_store::FsRuntimeStoreOptions;
 use worker_runtime::http_server::{
     RuntimeHttpConfigBundleAvailabilityResponse, RuntimeHttpConfigBundleSyncRequest,
-    RuntimeHttpErrorResponse, RuntimeHttpSummaryResponse, RuntimeHttpWorkerDeleteResponse,
+    RuntimeHttpErrorResponse, RuntimeHttpSummaryResponse, RuntimeHttpWorkerCompletionsRequest,
+    RuntimeHttpWorkerCompletionsResponse, RuntimeHttpWorkerDeleteResponse,
     RuntimeHttpWorkerInputResponse, RuntimeHttpWorkerLifecycleRequest,
     RuntimeHttpWorkerLifecycleResponse, RuntimeHttpWorkerResponse, RuntimeHttpWorkersResponse,
     RuntimeHttpWorkingDirectoriesResponse, RuntimeHttpWorkingDirectoryResponse,
@@ -436,6 +437,9 @@ pub struct WorkerLifecycleResult {
 pub enum WorkerInputKind {
     User,
     System,
+    Compact,
+    ListRewindTargets,
+    RegisterPeer,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
@@ -452,6 +456,25 @@ pub struct WorkerInputRequest {
     #[serde(default = "default_worker_input_kind")]
     pub kind: WorkerInputKind,
     pub content: String,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub segments: Option<Vec<protocol::Segment>>,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
+pub struct WorkerCompletionsRequest {
+    pub kind: protocol::CompletionKind,
+    #[serde(default)]
+    pub prefix: String,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
+pub struct WorkerCompletionsResult {
+    pub runtime_id: String,
+    pub worker_id: String,
+    pub kind: protocol::CompletionKind,
+    pub prefix: String,
+    pub entries: Vec<protocol::CompletionEntry>,
+    pub diagnostics: Vec<RuntimeDiagnostic>,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
@@ -712,6 +735,25 @@ pub trait WorkspaceWorkerRuntime: Send + Sync {
         }
     }
 
+    fn worker_completions(
+        &self,
+        worker_id: &str,
+        request: WorkerCompletionsRequest,
+    ) -> WorkerCompletionsResult {
+        WorkerCompletionsResult {
+            runtime_id: self.runtime_id().to_string(),
+            worker_id: worker_id.to_string(),
+            kind: request.kind,
+            prefix: request.prefix,
+            entries: Vec::new(),
+            diagnostics: vec![diagnostic(
+                "worker_completions_unsupported",
+                DiagnosticSeverity::Info,
+                format!("runtime does not implement completions for worker '{worker_id}'"),
+            )],
+        }
+    }
+
     fn proxy_connect_points(&self, worker_id: &str) -> Vec<WorkerProxyConnectPoint> {
         vec![WorkerProxyConnectPoint {
             kind: "stream_proxy".to_string(),
@@ -1020,6 +1062,26 @@ impl RuntimeRegistry {
         Ok(runtime.send_input(worker_id, request))
     }
 
+    pub fn worker_completions(
+        &self,
+        runtime_id: &str,
+        worker_id: &str,
+        request: WorkerCompletionsRequest,
+    ) -> Result<WorkerCompletionsResult, RuntimeRegistryError> {
+        validate_backend_identifier("runtime_id", runtime_id)?;
+        validate_backend_identifier("worker_id", worker_id)?;
+        let runtime = self.runtime(runtime_id)?;
+        let lookup = runtime.worker(worker_id);
+        if lookup.worker.is_none() {
+            return Err(operation_failed_or_unknown_worker(
+                runtime_id,
+                worker_id,
+                lookup.diagnostics,
+            ));
+        }
+        Ok(runtime.worker_completions(worker_id, request))
+    }
+
     pub fn stop_worker(
         &self,
         runtime_id: &str,
@@ -1750,8 +1812,12 @@ impl WorkspaceWorkerRuntime for EmbeddedWorkerRuntime {
             kind: match request.kind {
                 WorkerInputKind::User => EmbeddedWorkerInputKind::User,
                 WorkerInputKind::System => EmbeddedWorkerInputKind::System,
+                WorkerInputKind::Compact => EmbeddedWorkerInputKind::Compact,
+                WorkerInputKind::ListRewindTargets => EmbeddedWorkerInputKind::ListRewindTargets,
+                WorkerInputKind::RegisterPeer => EmbeddedWorkerInputKind::RegisterPeer,
             },
             content: request.content,
+            segments: request.segments,
         };
         match self.runtime.send_input(&worker_ref, input) {
             Ok(ack) => WorkerInputResult {
@@ -1768,6 +1834,64 @@ impl WorkspaceWorkerRuntime for EmbeddedWorkerRuntime {
             ),
         }
     }
+
+    fn worker_completions(
+        &self,
+        worker_id: &str,
+        request: WorkerCompletionsRequest,
+    ) -> WorkerCompletionsResult {
+        if !self.execution_enabled {
+            return WorkerCompletionsResult {
+                runtime_id: self.runtime_id.clone(),
+                worker_id: worker_id.to_string(),
+                kind: request.kind,
+                prefix: request.prefix,
+                entries: Vec::new(),
+                diagnostics: vec![diagnostic(
+                    "embedded_worker_execution_unavailable",
+                    DiagnosticSeverity::Info,
+                    format!(
+                        "worker completions for '{worker_id}' require an embedded execution backend"
+                    ),
+                )],
+            };
+        }
+        let Some(worker_ref) = self.worker_ref(worker_id) else {
+            return WorkerCompletionsResult {
+                runtime_id: self.runtime_id.clone(),
+                worker_id: worker_id.to_string(),
+                kind: request.kind,
+                prefix: request.prefix,
+                entries: Vec::new(),
+                diagnostics: vec![diagnostic(
+                    "embedded_worker_id_invalid",
+                    DiagnosticSeverity::Warning,
+                    "Worker id was empty and cannot be resolved".to_string(),
+                )],
+            };
+        };
+        match self
+            .runtime
+            .worker_completions(&worker_ref, request.kind, &request.prefix)
+        {
+            Ok(entries) => WorkerCompletionsResult {
+                runtime_id: self.runtime_id.clone(),
+                worker_id: worker_id.to_string(),
+                kind: request.kind,
+                prefix: request.prefix,
+                entries,
+                diagnostics: Vec::new(),
+            },
+            Err(error) => WorkerCompletionsResult {
+                runtime_id: self.runtime_id.clone(),
+                worker_id: worker_id.to_string(),
+                kind: request.kind,
+                prefix: request.prefix,
+                entries: Vec::new(),
+                diagnostics: vec![embedded_runtime_diagnostic(&error)],
+            },
+        }
+    }
 }
 
 #[derive(Clone)]
@@ -2397,8 +2521,12 @@ impl WorkspaceWorkerRuntime for RemoteWorkerRuntime {
             kind: match request.kind {
                 WorkerInputKind::User => EmbeddedWorkerInputKind::User,
                 WorkerInputKind::System => EmbeddedWorkerInputKind::System,
+                WorkerInputKind::Compact => EmbeddedWorkerInputKind::Compact,
+                WorkerInputKind::ListRewindTargets => EmbeddedWorkerInputKind::ListRewindTargets,
+                WorkerInputKind::RegisterPeer => EmbeddedWorkerInputKind::RegisterPeer,
             },
             content: request.content,
+            segments: request.segments,
         };
         match self.post_json::<_, RuntimeHttpWorkerInputResponse>(
             &format!("/v1/workers/{worker_id}/input"),
@@ -2414,6 +2542,38 @@ impl WorkspaceWorkerRuntime for RemoteWorkerRuntime {
             Err(diagnostic) => remote_input_rejected(&self.runtime_id, worker_id, diagnostic),
         }
     }
+
+    fn worker_completions(
+        &self,
+        worker_id: &str,
+        request: WorkerCompletionsRequest,
+    ) -> WorkerCompletionsResult {
+        let request = RuntimeHttpWorkerCompletionsRequest {
+            kind: request.kind,
+            prefix: request.prefix,
+        };
+        match self.post_json::<_, RuntimeHttpWorkerCompletionsResponse>(
+            &format!("/v1/workers/{worker_id}/completions"),
+            &request,
+        ) {
+            Ok(response) => WorkerCompletionsResult {
+                runtime_id: self.runtime_id.clone(),
+                worker_id: worker_id.to_string(),
+                kind: response.kind,
+                prefix: response.prefix,
+                entries: response.entries,
+                diagnostics: Vec::new(),
+            },
+            Err(diagnostic) => WorkerCompletionsResult {
+                runtime_id: self.runtime_id.clone(),
+                worker_id: worker_id.to_string(),
+                kind: request.kind,
+                prefix: request.prefix,
+                entries: Vec::new(),
+                diagnostics: vec![diagnostic],
+            },
+        }
+    }
 }
 
 fn embedded_runtime_capabilities(
@@ -3676,6 +3836,7 @@ mod tests {
         request.initial_input = Some(EmbeddedWorkerInput {
             kind: EmbeddedWorkerInputKind::System,
             content: "system/role instruction belongs in profile".to_string(),
+            segments: None,
         });
 
         let spawned = runtime.spawn_worker(request);
@@ -3707,6 +3868,7 @@ mod tests {
             WorkerInputRequest {
                 kind: WorkerInputKind::User,
                 content: "hello".to_string(),
+                segments: None,
             },
         );
         assert_eq!(input.state, WorkerOperationState::Accepted);
@@ -3792,6 +3954,7 @@ mod tests {
                 WorkerInputRequest {
                     kind: WorkerInputKind::User,
                     content: "hello embedded runtime".to_string(),
+                    segments: None,
                 },
             )
             .unwrap();
@@ -4007,6 +4170,7 @@ mod tests {
                 WorkerInputRequest {
                     kind: WorkerInputKind::User,
                     content: "hello remote".to_string(),
+                    segments: None,
                 },
             )
             .unwrap();

crates/workspace-server/src/server.rs

@@ -28,10 +28,10 @@ use crate::hosts::{
     ConfigBundleCheckResult, ConfigBundleSyncResult, DiagnosticSeverity, EmbeddedWorkerRuntime,
     HostSummary, RemoteRuntimeConfig, RemoteWorkerRuntime, RuntimeDiagnostic, RuntimeRegistry,
     RuntimeRegistryError, RuntimeRegistryUnregisterResult, RuntimeSummary, WorkerCapabilitySummary,
-    WorkerImplementationSummary, WorkerInputRequest, WorkerInputResult, WorkerLifecycleRequest,
-    WorkerLifecycleResult, WorkerOperationState, WorkerSpawnAcceptanceRequirement,
-    WorkerSpawnIntent, WorkerSpawnRequest, WorkerSpawnResult, WorkerSpawnWorkingDirectoryRequest,
-    WorkerSummary, WorkerWorkspaceSummary,
+    WorkerCompletionsRequest, WorkerCompletionsResult, WorkerImplementationSummary,
+    WorkerInputRequest, WorkerInputResult, WorkerLifecycleRequest, WorkerLifecycleResult,
+    WorkerOperationState, WorkerSpawnAcceptanceRequirement, WorkerSpawnIntent, WorkerSpawnRequest,
+    WorkerSpawnResult, WorkerSpawnWorkingDirectoryRequest, WorkerSummary, WorkerWorkspaceSummary,
 };
 use crate::identity::WorkspaceIdentity;
 use crate::observation::{
@@ -496,6 +496,14 @@ pub fn build_router(api: WorkspaceApi) -> Router {
             "/api/w/{workspace_id}/runtimes/{runtime_id}/workers/{worker_id}/input",
             post(scoped_send_runtime_worker_input),
         )
+        .route(
+            "/api/runtimes/{runtime_id}/workers/{worker_id}/completions",
+            post(runtime_worker_completions),
+        )
+        .route(
+            "/api/w/{workspace_id}/runtimes/{runtime_id}/workers/{worker_id}/completions",
+            post(scoped_runtime_worker_completions),
+        )
         .route(
             "/api/runtimes/{runtime_id}/workers/{worker_id}/stop",
             post(stop_runtime_worker),
@@ -2252,6 +2260,20 @@ async fn scoped_send_runtime_worker_input(
     .await
 }
 
+async fn scoped_runtime_worker_completions(
+    State(api): State<WorkspaceApi>,
+    AxumPath(path): AxumPath<ScopedRuntimeWorkerPath>,
+    Json(request): Json<WorkerCompletionsRequest>,
+) -> ApiResult<Json<WorkerCompletionsResult>> {
+    validate_workspace_scope(&api, &path.workspace_id)?;
+    runtime_worker_completions(
+        State(api),
+        AxumPath((path.runtime_id, path.worker_id)),
+        Json(request),
+    )
+    .await
+}
+
 async fn scoped_stop_runtime_worker(
     State(api): State<WorkspaceApi>,
     AxumPath(path): AxumPath<ScopedRuntimeWorkerPath>,
@@ -2786,6 +2808,7 @@ async fn create_workspace_worker(
         Some(EmbeddedWorkerInput {
             kind: EmbeddedWorkerInputKind::User,
             content: initial_text,
+            segments: None,
         })
     };
     let selected_working_directory_id = request
@@ -3137,6 +3160,18 @@ async fn send_runtime_worker_input(
     Ok(Json(result))
 }
 
+async fn runtime_worker_completions(
+    State(api): State<WorkspaceApi>,
+    AxumPath((runtime_id, worker_id)): AxumPath<(String, String)>,
+    Json(request): Json<WorkerCompletionsRequest>,
+) -> ApiResult<Json<WorkerCompletionsResult>> {
+    let result = api
+        .runtime
+        .worker_completions(&runtime_id, &worker_id, request)
+        .map_err(|err| err.into_error())?;
+    Ok(Json(result))
+}
+
 async fn stop_runtime_worker(
     State(api): State<WorkspaceApi>,
     AxumPath((runtime_id, worker_id)): AxumPath<(String, String)>,
@@ -7237,6 +7272,7 @@ mod tests {
                 WorkerInputRequest {
                     kind: WorkerInputKind::User,
                     content: "persist me".to_string(),
+                    segments: None,
                 },
             )
             .expect("send input");
@@ -7298,6 +7334,7 @@ mod tests {
                 WorkerInputRequest {
                     kind: WorkerInputKind::User,
                     content: "should not be routed to stale handle".to_string(),
+                    segments: None,
                 },
             )
             .expect("stale worker input is projected as an operation result");

resources/profiles/default.dcdl

@@ -14,6 +14,13 @@ engine = {
     reasoning = "high";
 };
 
+compaction = {
+    kind = "tokens";
+    threshold = 240000;
+    request_threshold = 270000;
+    worker_context_max_tokens = 100000;
+};
+
 feature = {
     task = { enabled = true; };
     memory = { enabled = true; };

web/workspace/deno.json

@@ -6,7 +6,7 @@
     "dev": "deno run -A npm:vite@7.2.7 dev",
     "dev:backend": "cd ../.. && cargo run -p yoi-workspace-server -- serve --workspace . --db .yoi/workspace.db --listen 127.0.0.1:8787",
     "check": "deno run -A npm:@sveltejs/kit@2.49.4 sync && deno run -A npm:svelte-check@4.3.4 --tsconfig ./tsconfig.json",
-    "test": "deno test --allow-read=src --allow-env=VSCODE_TEXTMATE_DEBUG src/lib/workspace-api/http.test.ts src/lib/workspace-console/chat-submit.test.ts src/lib/workspace-console/markdown.test.ts src/lib/workspace-console/model.test.ts src/lib/workspace-console/worker-console.ui.test.ts src/lib/workspace-settings/model.test.ts src/lib/workspace-sidebar/workers.test.ts src/lib/workspace-sidebar/worker-launch.test.ts src/lib/workspace-sidebar/repository-nav.test.ts",
+    "test": "deno test --allow-read=src --allow-env=VSCODE_TEXTMATE_DEBUG src/lib/workspace-api/http.test.ts src/lib/workspace-console/chat-submit.test.ts src/lib/workspace-console/composer-command.test.ts src/lib/workspace-console/composer-completion.test.ts src/lib/workspace-console/markdown.test.ts src/lib/workspace-console/model.test.ts src/lib/workspace-console/worker-console.ui.test.ts src/lib/workspace-settings/model.test.ts src/lib/workspace-sidebar/workers.test.ts src/lib/workspace-sidebar/worker-launch.test.ts src/lib/workspace-sidebar/repository-nav.test.ts",
     "build": "deno run -A npm:vite@7.2.7 build",
     "preview": "deno run -A npm:vite@7.2.7 preview"
   },

web/workspace/src/app.css

@@ -1383,6 +1383,15 @@
     color: var(--text-muted);
 }
 
+.composer-completions {
+    display: flex;
+    flex-wrap: wrap;
+    gap: var(--space-2);
+    align-items: center;
+    color: var(--text-muted);
+    font-size: 0.86rem;
+}
+
 @media (max-width: 960px) {
     .console-header {
         flex-direction: column;

web/workspace/src/lib/workspace-console/chat-submit.test.ts

@@ -18,20 +18,30 @@ function assertEquals<T>(actual: T, expected: T): void {
   }
 }
 
-Deno.test("shouldSubmitChatKey defaults to Cmd+Enter submit behavior", () => {
+Deno.test("shouldSubmitChatKey supports platform-auto submit modifier", () => {
+  assert(
+    shouldSubmitChatKey(
+      { key: "Enter", ctrlKey: true },
+      { mode: "mod-enter", modKey: "auto", enabled: true },
+    ),
+    "Ctrl+Enter should submit on non-Apple platforms",
+  );
+  assertEquals(
+    shouldSubmitChatKey(
+      { key: "Enter" },
+      { mode: "mod-enter", modKey: "auto", enabled: true },
+    ),
+    false,
+  );
+});
+
+Deno.test("shouldSubmitChatKey still supports explicit Cmd+Enter behavior", () => {
   assert(
     shouldSubmitChatKey(
       { key: "Enter", metaKey: true },
       { mode: "mod-enter", modKey: "meta", enabled: true },
     ),
-    "Cmd+Enter should submit by default",
-  );
-  assertEquals(
-    shouldSubmitChatKey(
-      { key: "Enter" },
-      { mode: "mod-enter", modKey: "meta", enabled: true },
-    ),
-    false,
+    "Cmd+Enter should submit when meta is selected",
   );
   assertEquals(
     shouldSubmitChatKey(

web/workspace/src/lib/workspace-console/chat-submit.ts

@@ -26,7 +26,7 @@ export type ChatSubmitKeyEventLike = {
 function normalizeOptions(options: ChatSubmitOptions): NormalizedChatSubmitOptions {
   return {
     mode: "mod-enter",
-    modKey: "meta",
+    modKey: "auto",
     allowEmptySubmit: false,
     stopPropagation: false,
     enabled: true,

web/workspace/src/lib/workspace-console/composer-command.test.ts

@@ -0,0 +1,64 @@
+import { buildComposerRequest, parseSigilSegments } from "./composer-command.ts";
+
+declare const Deno: {
+  test(name: string, fn: () => void): void;
+};
+
+function assert(condition: unknown, message: string): asserts condition {
+  if (!condition) {
+    throw new Error(message);
+  }
+}
+
+function assertEquals<T>(actual: T, expected: T): void {
+  const actualJson = JSON.stringify(actual);
+  const expectedJson = JSON.stringify(expected);
+  if (actualJson !== expectedJson) {
+    throw new Error(`Expected ${expectedJson}, got ${actualJson}`);
+  }
+}
+
+Deno.test("parseSigilSegments converts TUI-style references", () => {
+  assertEquals(parseSigilSegments("read @src/main.rs then #memory and /workflow"), [
+    { kind: "text", content: "read " },
+    { kind: "file_ref", path: "src/main.rs" },
+    { kind: "text", content: " then " },
+    { kind: "knowledge_ref", slug: "memory" },
+    { kind: "text", content: " and " },
+    { kind: "workflow_invoke", slug: "workflow" },
+  ]);
+});
+
+Deno.test("buildComposerRequest sends user segments when sigils are present", () => {
+  const result = buildComposerRequest("inspect @README.md");
+  assert(result.ok, "request should be accepted");
+  assertEquals(result.request?.kind, "user");
+  assertEquals(result.request?.content, "inspect @README.md");
+  assertEquals(result.request?.segments, [
+    { kind: "text", content: "inspect " },
+    { kind: "file_ref", path: "README.md" },
+  ]);
+});
+
+Deno.test("buildComposerRequest parses colon commands", () => {
+  const compact = buildComposerRequest(":compact");
+  assert(compact.ok, "compact should be accepted");
+  assertEquals(compact.request, { kind: "compact", content: "" });
+
+  const peer = buildComposerRequest(":peer companion");
+  assert(peer.ok, "peer should be accepted");
+  assertEquals(peer.request, { kind: "register_peer", content: "companion" });
+
+  const help = buildComposerRequest(":help compact");
+  assert(help.ok, "help should be accepted");
+  assertEquals(help.request, undefined);
+  assert(help.notice?.includes(":compact"), "help should return a local notice");
+});
+
+Deno.test("buildComposerRequest rejects invalid colon commands", () => {
+  const unknown = buildComposerRequest(":does-not-exist");
+  assert(!unknown.ok, "unknown command should be rejected");
+
+  const invalidPeer = buildComposerRequest(":peer");
+  assert(!invalidPeer.ok, "invalid peer command should be rejected");
+});

web/workspace/src/lib/workspace-console/composer-command.ts

@@ -0,0 +1,208 @@
+import type { Segment } from "$lib/generated/protocol";
+
+export type WorkerConsoleInputKind =
+  | "user"
+  | "system"
+  | "compact"
+  | "list_rewind_targets"
+  | "register_peer";
+
+export type WorkerConsoleInputRequest = {
+  kind: WorkerConsoleInputKind;
+  content: string;
+  segments?: Segment[];
+};
+
+export type ComposerCommandResult =
+  | { ok: true; request?: WorkerConsoleInputRequest; notice?: string }
+  | { ok: false; message: string };
+
+type CommandSpec = {
+  usage: string;
+  description: string;
+};
+
+const COMMANDS: Record<string, CommandSpec> = {
+  help: {
+    usage: ":help [command]",
+    description: "Show available Web Console commands or details for one command.",
+  },
+  "?": {
+    usage: ":? [command]",
+    description: "Alias for :help.",
+  },
+  noop: {
+    usage: ":noop",
+    description: "Validate command dispatch without side effects.",
+  },
+  compact: {
+    usage: ":compact",
+    description: "Request immediate Worker context compaction.",
+  },
+  rewind: {
+    usage: ":rewind",
+    description: "Ask the Worker for rewind targets.",
+  },
+  rollback: {
+    usage: ":rollback",
+    description: "Alias for :rewind.",
+  },
+  peer: {
+    usage: ":peer <worker-name>",
+    description: "Register another existing Worker as a reciprocal metadata peer.",
+  },
+  system: {
+    usage: ":system <message>",
+    description: "Send an agent-visible system notification to the Worker.",
+  },
+};
+
+export function buildComposerRequest(value: string): ComposerCommandResult {
+  const content = value.trim();
+  if (!content) {
+    return { ok: false, message: "Input is empty." };
+  }
+  if (content.startsWith(":")) {
+    return buildColonCommand(content.slice(1));
+  }
+  const segments = parseSigilSegments(content);
+  return {
+    ok: true,
+    request: {
+      kind: "user",
+      content,
+      segments: segments.some((segment) => segment.kind !== "text") ? segments : undefined,
+    },
+  };
+}
+
+function buildColonCommand(commandLine: string): ComposerCommandResult {
+  const [name = "", ...argv] = commandLine.trim().split(/\s+/).filter(Boolean);
+  if (!name) {
+    return {
+      ok: false,
+      message: "Empty command. Type :help for available commands.",
+    };
+  }
+  switch (name) {
+    case "help":
+    case "?":
+      return helpCommand(argv);
+    case "noop":
+      if (argv.length > 0) {
+        return invalidUsage("noop");
+      }
+      return { ok: true, notice: "noop: no action" };
+    case "compact":
+      if (argv.length > 0) {
+        return invalidUsage("compact");
+      }
+      return { ok: true, request: { kind: "compact", content: "" }, notice: "compact requested" };
+    case "rewind":
+    case "rollback":
+      if (argv.length > 0) {
+        return invalidUsage("rewind");
+      }
+      return { ok: true, request: { kind: "list_rewind_targets", content: "" }, notice: "rewind targets requested" };
+    case "peer":
+      if (argv.length !== 1) {
+        return invalidUsage("peer");
+      }
+      return {
+        ok: true,
+        request: { kind: "register_peer", content: argv[0] },
+        notice: `peer metadata registration requested with \`${argv[0]}\``,
+      };
+    case "system": {
+      const message = commandLine.trim().slice(name.length).trimStart();
+      if (!message) {
+        return invalidUsage("system");
+      }
+      return { ok: true, request: { kind: "system", content: message } };
+    }
+    default:
+      return {
+        ok: false,
+        message: `Unknown command: ${name}. Type :help for available commands.`,
+      };
+  }
+}
+
+function helpCommand(argv: string[]): ComposerCommandResult {
+  if (argv.length > 1) {
+    return invalidUsage("help");
+  }
+  const name = argv[0];
+  if (name) {
+    const spec = COMMANDS[name];
+    if (!spec) {
+      return {
+        ok: false,
+        message: `Unknown command: ${name}. Type :help for available commands.`,
+      };
+    }
+    return {
+      ok: true,
+      notice: `command: ${name} — usage: ${spec.usage}. ${spec.description}`,
+    };
+  }
+  const list = ["help", "noop", "compact", "rewind", "peer", "system"]
+    .map((command) => `${command} (${COMMANDS[command].usage})`)
+    .join(", ");
+  return {
+    ok: true,
+    notice: `available commands: ${list}`,
+  };
+}
+
+function invalidUsage(name: string): ComposerCommandResult {
+  return { ok: false, message: `Invalid arguments. Usage: ${COMMANDS[name].usage}` };
+}
+
+export function parseSigilSegments(input: string): Segment[] {
+  const segments: Segment[] = [];
+  const pattern = /(^|\s)([@#/])([^\s]+)/g;
+  let cursor = 0;
+  let match: RegExpExecArray | null;
+  while ((match = pattern.exec(input)) !== null) {
+    const leading = match[1] ?? "";
+    const sigil = match[2];
+    const value = match[3];
+    const atomStart = match.index + leading.length;
+    if (atomStart > cursor) {
+      segments.push({ kind: "text", content: input.slice(cursor, atomStart) });
+    }
+    segments.push(sigilSegment(sigil, value));
+    cursor = atomStart + sigil.length + value.length;
+  }
+  if (cursor < input.length) {
+    segments.push({ kind: "text", content: input.slice(cursor) });
+  }
+  return coalesceTextSegments(segments.length > 0 ? segments : [{ kind: "text", content: input }]);
+}
+
+function sigilSegment(sigil: string, value: string): Segment {
+  switch (sigil) {
+    case "@":
+      return { kind: "file_ref", path: value };
+    case "#":
+      return { kind: "knowledge_ref", slug: value };
+    case "/":
+      return { kind: "workflow_invoke", slug: value };
+    default:
+      return { kind: "text", content: `${sigil}${value}` };
+  }
+}
+
+function coalesceTextSegments(segments: Segment[]): Segment[] {
+  const coalesced: Segment[] = [];
+  for (const segment of segments) {
+    const last = coalesced.at(-1);
+    if (segment.kind === "text" && last?.kind === "text") {
+      last.content += segment.content;
+    } else {
+      coalesced.push(segment);
+    }
+  }
+  return coalesced;
+}

web/workspace/src/lib/workspace-console/composer-completion.test.ts

@@ -0,0 +1,54 @@
+import {
+  applyCompletion,
+  completionTokenAt,
+  localCommandCompletions,
+} from "./composer-completion.ts";
+
+declare const Deno: {
+  test(name: string, fn: () => void): void;
+};
+
+function assert(condition: unknown, message: string): asserts condition {
+  if (!condition) {
+    throw new Error(message);
+  }
+}
+
+function assertEquals<T>(actual: T, expected: T): void {
+  const actualJson = JSON.stringify(actual);
+  const expectedJson = JSON.stringify(expected);
+  if (actualJson !== expectedJson) {
+    throw new Error(`Expected ${expectedJson}, got ${actualJson}`);
+  }
+}
+
+Deno.test("completionTokenAt detects TUI-style sigils before the cursor", () => {
+  assertEquals(completionTokenAt("open @src/ma", "open @src/ma".length), {
+    sigil: "@",
+    kind: "file",
+    start: 5,
+    end: 12,
+    prefix: "src/ma",
+  });
+  assertEquals(completionTokenAt(":comp", 5)?.kind, "command");
+  assertEquals(completionTokenAt("ask #mem", 8)?.kind, "knowledge");
+  assertEquals(completionTokenAt("run /work", 9)?.kind, "workflow");
+});
+
+Deno.test("applyCompletion replaces the active token and advances the cursor", () => {
+  const value = "open @src/ma please";
+  const token = completionTokenAt(value, "open @src/ma".length);
+  assert(token, "token should exist");
+  assertEquals(applyCompletion(value, token, { value: "src/main.rs" }), {
+    value: "open @src/main.rs please",
+    cursor: "open @src/main.rs ".length,
+  });
+  assertEquals(applyCompletion(value, token, { value: "src", is_dir: true }), {
+    value: "open @src/ please",
+    cursor: "open @src/".length,
+  });
+});
+
+Deno.test("localCommandCompletions filters colon commands", () => {
+  assertEquals(localCommandCompletions("com").map((entry) => entry.value), ["compact"]);
+});

web/workspace/src/lib/workspace-console/composer-completion.ts

@@ -0,0 +1,85 @@
+export type ComposerCompletionKind = "command" | "file" | "knowledge" | "workflow";
+
+export type ComposerCompletionToken = {
+  sigil: ":" | "@" | "#" | "/";
+  kind: ComposerCompletionKind;
+  start: number;
+  end: number;
+  prefix: string;
+};
+
+export type ComposerCompletionEntry = {
+  value: string;
+  is_dir?: boolean;
+  description?: string;
+};
+
+export type CompletionApplyResult = {
+  value: string;
+  cursor: number;
+};
+
+export const COLON_COMMAND_COMPLETIONS: ComposerCompletionEntry[] = [
+  { value: "help", description: "Show commands" },
+  { value: "noop", description: "No-op" },
+  { value: "compact", description: "Compact Worker context" },
+  { value: "rewind", description: "List rewind targets" },
+  { value: "rollback", description: "Alias for rewind" },
+  { value: "peer", description: "Register metadata peer" },
+  { value: "system", description: "Send system notification" },
+];
+
+export function completionTokenAt(
+  value: string,
+  cursor: number,
+): ComposerCompletionToken | null {
+  const boundedCursor = Math.max(0, Math.min(cursor, value.length));
+  const before = value.slice(0, boundedCursor);
+  const match = /(^|\s)([:@#/])([^\s]*)$/.exec(before);
+  if (!match) {
+    return null;
+  }
+  const sigil = match[2] as ComposerCompletionToken["sigil"];
+  const prefix = match[3] ?? "";
+  const tokenStart = before.length - prefix.length - sigil.length;
+  return {
+    sigil,
+    kind: completionKindForSigil(sigil),
+    start: tokenStart,
+    end: boundedCursor,
+    prefix,
+  };
+}
+
+export function localCommandCompletions(prefix: string): ComposerCompletionEntry[] {
+  const normalized = prefix.toLowerCase();
+  return COLON_COMMAND_COMPLETIONS.filter((entry) =>
+    entry.value.toLowerCase().startsWith(normalized)
+  );
+}
+
+export function applyCompletion(
+  value: string,
+  token: ComposerCompletionToken,
+  entry: ComposerCompletionEntry,
+): CompletionApplyResult {
+  const suffix = entry.is_dir ? "/" : " ";
+  const replacement = `${token.sigil}${entry.value}${suffix}`;
+  const restStart = !entry.is_dir && value[token.end] === " " ? token.end + 1 : token.end;
+  const next = `${value.slice(0, token.start)}${replacement}${value.slice(restStart)}`;
+  const cursor = token.start + replacement.length;
+  return { value: next, cursor };
+}
+
+function completionKindForSigil(sigil: ComposerCompletionToken["sigil"]): ComposerCompletionKind {
+  switch (sigil) {
+    case ":":
+      return "command";
+    case "@":
+      return "file";
+    case "#":
+      return "knowledge";
+    case "/":
+      return "workflow";
+  }
+}

web/workspace/src/lib/workspace-console/model.test.ts

@@ -349,6 +349,118 @@ Deno.test("projectConsole keeps Grep error detail in the body", () => {
   );
 });
 
+Deno.test("projectConsole renders alert events", () => {
+  const projection = projectConsole([
+    {
+      eventId: "alert-1",
+      event: {
+        event: "alert",
+        data: {
+          level: "warn",
+          source: "compactor",
+          message: "manual compaction skipped",
+          timestamp_ms: 1,
+        },
+      } satisfies Event,
+    },
+    {
+      eventId: "alert-2",
+      event: {
+        event: "alert",
+        data: {
+          level: "error",
+          source: "engine",
+          message: "provider failed",
+          timestamp_ms: 2,
+        },
+      } satisfies Event,
+    },
+  ]);
+
+  assertEquals(projection.lines.length, 2);
+  assertEquals(projection.lines[0].kind, "status");
+  assertEquals(projection.lines[0].title, "Alert · compactor");
+  assertEquals(projection.lines[0].body, "manual compaction skipped");
+  assertEquals(projection.lines[0].error, false);
+  assertEquals(projection.lines[1].kind, "error");
+  assertEquals(projection.lines[1].title, "Alert · engine");
+  assertEquals(projection.lines[1].body, "provider failed");
+  assertEquals(projection.lines[1].error, true);
+});
+
+Deno.test("projectConsole shows compact progress as a status block", () => {
+  const projection = projectConsole([
+    {
+      eventId: "compact-1",
+      event: { event: "compact_start" } satisfies Event,
+    },
+  ]);
+
+  assertEquals(projection.lines.length, 1);
+  assertEquals(projection.lines[0].id, "status-compact");
+  assertEquals(projection.lines[0].kind, "status");
+  assertEquals(projection.lines[0].body, "Compacting…");
+  assertEquals(projection.lines[0].streaming, true);
+
+  const completed = projectConsole([
+    {
+      eventId: "compact-1",
+      event: { event: "compact_start" } satisfies Event,
+    },
+    {
+      eventId: "compact-2",
+      event: {
+        event: "compact_done",
+        data: { new_segment_id: "00000000-0000-0000-0000-000000000001" },
+      } satisfies Event,
+    },
+  ]);
+
+  assertEquals(completed.lines.length, 1);
+  assertEquals(completed.lines[0].id, "status-compact");
+  assertEquals(completed.lines[0].body, "Compacted.");
+  assertEquals(completed.lines[0].streaming, false);
+});
+
+Deno.test("createConsoleProjector updates only compact status block", () => {
+  const projector = createConsoleProjector();
+  let projection = projector.append([
+    {
+      eventId: "compact-identity-1",
+      event: {
+        event: "user_message",
+        data: { segments: [{ kind: "text", content: "hello" }] },
+      } satisfies Event,
+    },
+    {
+      eventId: "compact-identity-2",
+      event: { event: "compact_start" } satisfies Event,
+    },
+  ]);
+  const userLine = projection.lines[0];
+  const compactLine = projection.lines[1];
+
+  projection = projector.append([
+    {
+      eventId: "compact-identity-3",
+      event: {
+        event: "compact_done",
+        data: { new_segment_id: "00000000-0000-0000-0000-000000000001" },
+      } satisfies Event,
+    },
+  ]);
+
+  assert(
+    projection.lines[0] === userLine,
+    "unrelated message line should keep object identity",
+  );
+  assert(
+    projection.lines[1] !== compactLine,
+    "compact status line should update object identity",
+  );
+  assertEquals(projection.lines[1].body, "Compacted.");
+});
+
 Deno.test("projectConsole keeps streaming tool call updates in the same Call block", () => {
   const projection = projectConsole([
     {
@@ -680,6 +792,18 @@ Deno.test("projectConsole renders snapshot entries and in-flight output", () =>
                 is_error: false,
               },
             },
+            {
+              kind: "extension",
+              ts: 6,
+              domain: "yoi.compaction",
+              payload: {
+                kind: "compaction_block",
+                schema_version: 1,
+                block_id: "compact",
+                state: "running",
+                message: "Compacting…",
+              },
+            },
           ],
           greeting: {
             worker_name: "Worker",
@@ -710,6 +834,7 @@ Deno.test("projectConsole renders snapshot entries and in-flight output", () =>
       "user:new user:false",
       "assistant:assistant reply:false",
       "tool:Read — 1 file read\n  /tmp/a.md:false",
+      "status:Compacting…:true",
       "in_flight:partial:true",
     ],
   );

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

@@ -1,5 +1,6 @@
 import type {
   Event as ProtocolEvent,
+  Alert,
   InFlightBlock,
   InFlightToolCallState,
   Segment,
@@ -262,7 +263,10 @@ export function applyProtocolEvent(
     case "llm_retry":
     case "llm_continuation":
     case "run_end":
+      break;
     case "alert":
+      appendAlertLine(next, envelope.eventId, event.data);
+      break;
     case "memory_worker":
     case "segment_rotated":
     case "completions":
@@ -271,22 +275,23 @@ export function applyProtocolEvent(
     case "workers_listed":
     case "worker_restored":
     case "peer_registered":
-    case "compact_start":
-    case "compact_done":
       // These are protocol/status/control events. TUI Console does not append
       // them to the conversation surface; browser Console should not either.
       break;
+    case "compact_start":
+      upsertStatusLine(next, "compact", envelope.eventId, "Compacting…", true);
+      break;
+    case "compact_done":
+      upsertStatusLine(next, "compact", envelope.eventId, "Compacted.", false);
+      break;
     case "compact_failed":
-      next.lines.push(
-        line(
-          envelope.eventId,
-          "error",
-          "compact failed",
-          event.data.error,
-          undefined,
-          false,
-          true,
-        ),
+      upsertStatusLine(
+        next,
+        "compact",
+        envelope.eventId,
+        `Compact failed: ${event.data.error}`,
+        false,
+        true,
       );
       break;
     case "shutdown":
@@ -341,6 +346,52 @@ function line(
   };
 }
 
+function upsertStatusLine(
+  projection: ConsoleProjection,
+  id: string,
+  eventId: string,
+  body: string,
+  streaming: boolean,
+  error = false,
+): void {
+  const lineId = `status-${id}`;
+  const index = projection.lines.findIndex((item) => item.id === lineId);
+  const item: ConsoleLine = {
+    id: lineId,
+    kind: error ? "error" : "status",
+    title: error ? "Status error" : "Status",
+    body,
+    eventId,
+    source: "event",
+    streaming,
+    error,
+  };
+  if (index >= 0) {
+    projection.lines[index] = item;
+  } else {
+    projection.lines.push(item);
+  }
+}
+
+function appendAlertLine(
+  projection: ConsoleProjection,
+  eventId: string,
+  alert: Alert,
+): void {
+  const isError = alert.level === "error";
+  projection.lines.push(
+    line(
+      eventId,
+      isError ? "error" : "status",
+      `Alert · ${alert.source}`,
+      alert.message,
+      undefined,
+      false,
+      isError,
+    ),
+  );
+}
+
 function findLastLineIndex(
   lines: ConsoleLine[],
   predicate: (line: ConsoleLine) => boolean,
@@ -943,11 +994,55 @@ function applyLogEntry(
     case "tool_result":
       applyLoggedItem(projection, eventId, entry["item"]);
       break;
+    case "extension":
+      applyExtensionEntry(projection, eventId, entry);
+      break;
     default:
       break;
   }
 }
 
+function applyExtensionEntry(
+  projection: ConsoleProjection,
+  eventId: string,
+  entry: Record<string, unknown>,
+) {
+  if (entry["domain"] !== "yoi.compaction") {
+    return;
+  }
+  const payload = entry["payload"];
+  if (!isRecord(payload) || payload["kind"] !== "compaction_block") {
+    return;
+  }
+  const blockId = stringField(payload, "block_id") || "compact";
+  const state = stringField(payload, "state") || "running";
+  const message = stringField(payload, "message") || compactMessageForState(state, payload);
+  upsertStatusLine(
+    projection,
+    blockId,
+    eventId,
+    message,
+    state === "running",
+    state === "failed",
+  );
+}
+
+function compactMessageForState(
+  state: string,
+  payload: Record<string, unknown>,
+): string {
+  switch (state) {
+    case "done":
+      return "Compacted.";
+    case "failed": {
+      const error = stringField(payload, "error");
+      return error ? `Compact failed: ${error}` : "Compact failed.";
+    }
+    default:
+      return "Compacting…";
+  }
+}
+
 function applyLoggedItem(
   projection: ConsoleProjection,
   eventId: string,

web/workspace/src/routes/w/[workspaceId]/runtimes/[runtimeId]/workers/[workerId]/console/+page.svelte

@@ -2,6 +2,14 @@
   import { tick } from 'svelte';
   import ConsoleLineItem from '$lib/workspace-console/ConsoleLineItem.svelte';
   import { chatSubmit } from '$lib/workspace-console/chat-submit';
+  import { buildComposerRequest } from '$lib/workspace-console/composer-command';
+  import {
+    applyCompletion,
+    completionTokenAt,
+    localCommandCompletions,
+    type ComposerCompletionEntry,
+    type ComposerCompletionToken
+  } from '$lib/workspace-console/composer-completion';
   import { fitTextarea } from '$lib/workspace-console/textarea-fit';
   import {
     createConsoleProjector,
@@ -35,12 +43,24 @@
     return workspaceApiPath(workspaceId, path);
   }
 
+  type WorkerCompletionsResult = {
+    kind: 'file' | 'knowledge' | 'workflow';
+    prefix: string;
+    entries: ComposerCompletionEntry[];
+    diagnostics: Diagnostic[];
+  };
+
   let worker = $state<Worker | null>(null);
   let liveWorkerState = $state<string | null>(null);
   let workerError = $state<string | null>(null);
   let draft = $state('');
+  let completionEntries = $state<ComposerCompletionEntry[]>([]);
+  let completionToken = $state<ComposerCompletionToken | null>(null);
+  let completionBusy = $state(false);
+  let completionError = $state<string | null>(null);
   let sending = $state(false);
   let sendError = $state<string | null>(null);
+  let composerNotice = $state<string | null>(null);
   let streamState = $state<'connecting' | 'open' | 'closed' | 'error'>('connecting');
   let streamDiagnostics = $state<Diagnostic[]>([]);
   let workerDetailsOpen = $state(false);
@@ -200,9 +220,80 @@
     return true;
   }
 
+  async function applyComposerCompletion(event: KeyboardEvent) {
+    const target = event.currentTarget;
+    if (!(target instanceof HTMLTextAreaElement)) {
+      return;
+    }
+    const token = completionTokenAt(draft, target.selectionStart ?? draft.length);
+    completionToken = token;
+    completionError = null;
+    if (!token) {
+      completionEntries = [];
+      return;
+    }
+
+    completionBusy = true;
+    try {
+      const entries = await resolveCompletionEntries(token);
+      completionEntries = entries;
+      if (entries.length === 0) {
+        completionError = `No completions for ${token.sigil}${token.prefix}`;
+        return;
+      }
+      const applied = applyCompletion(draft, token, entries[0]);
+      draft = applied.value;
+      await tick();
+      target.setSelectionRange(applied.cursor, applied.cursor);
+      composerNotice = entries.length > 1
+        ? `Completed ${token.sigil}${entries[0].value}; ${entries.length - 1} more candidate(s)`
+        : null;
+    } catch (error) {
+      completionError = error instanceof Error ? error.message : String(error);
+    } finally {
+      completionBusy = false;
+    }
+  }
+
+  async function resolveCompletionEntries(
+    token: ComposerCompletionToken
+  ): Promise<ComposerCompletionEntry[]> {
+    if (token.kind === 'command') {
+      return localCommandCompletions(token.prefix);
+    }
+    const result = await postJson<WorkerCompletionsResult>(
+      workerApiPath(
+        `/runtimes/${encodeURIComponent(runtimeId)}/workers/${encodeURIComponent(workerId)}/completions`
+      ),
+      { kind: token.kind, prefix: token.prefix }
+    );
+    if (result.diagnostics.length > 0 && result.entries.length === 0) {
+      throw new Error(diagnosticsToText(result.diagnostics));
+    }
+    return result.entries;
+  }
+
+  function handleComposerKeydown(event: KeyboardEvent) {
+    if (event.key !== 'Tab') {
+      return;
+    }
+    event.preventDefault();
+    void applyComposerCompletion(event);
+  }
+
   async function submitDraft(value = draft) {
-    const content = value.trim();
-    if (!content || sending || !inputReady) {
+    const command = buildComposerRequest(value);
+    if (!command.ok) {
+      composerNotice = null;
+      sendError = command.message;
+      return;
+    }
+    composerNotice = command.notice ?? null;
+    if (!command.request) {
+      draft = '';
+      return;
+    }
+    if (sending || !inputReady) {
       return;
     }
 
@@ -211,7 +302,7 @@
     try {
       const result = await postJson<WorkerInputResult>(
         workerApiPath(`/runtimes/${encodeURIComponent(runtimeId)}/workers/${encodeURIComponent(workerId)}/input`),
-        { kind: 'user', content }
+        command.request
       );
       if (result.state === 'accepted') {
         draft = '';
@@ -470,18 +561,34 @@
       <textarea
         id="worker-console-message"
         aria-label="Console input"
-        aria-keyshortcuts="Meta+Enter"
+        aria-keyshortcuts="Meta+Enter Control+Enter"
         bind:value={draft}
         use:chatSubmit={{
           enabled: inputReady && !sending,
           onSubmit: (value) => void submitDraft(value)
         }}
         use:fitTextarea={{ value: draft, maxRows: 10 }}
+        onkeydown={handleComposerKeydown}
         disabled={!inputReady || sending}
       ></textarea>
+      {#if completionBusy || completionError || completionEntries.length > 0}
+        <div class="composer-completions" aria-live="polite">
+          {#if completionBusy}
+            <span>completing…</span>
+          {:else if completionError}
+            <span class="error">{completionError}</span>
+          {:else}
+            <span>Tab: {completionToken?.sigil}{completionEntries[0]?.value}</span>
+            {#if completionEntries.length > 1}
+              <span>{completionEntries.length - 1} more</span>
+            {/if}
+          {/if}
+        </div>
+      {/if}
       <div class="composer-actions">
         <button type="submit" disabled={!canSend}>{sending ? 'Sending…' : 'Send'}</button>
-        {#if sendError}<p class="error">{sendError}</p>{/if}
+        {#if composerNotice}<p class="section-note">{composerNotice}</p>{/if}
+      {#if sendError}<p class="error">{sendError}</p>{/if}
       </div>
     </form>
 </div>