feat(cloud): expose steering controls for cloud sessions

packages/core/src/sessions/sessionService.ts

@@ -2901,7 +2901,11 @@ export class SessionService {
         isNotification(msg.method, POSTHOG_NOTIFICATIONS.RUN_STARTED)
       ) {
         const session = this.d.store.getSessions()[taskRunId];
-        const params = (msg as { params?: { agentVersion?: unknown } }).params;
+        const params = (
+          msg as {
+            params?: { agentVersion?: unknown; steering?: unknown };
+          }
+        ).params;
         const agentVersion =
           typeof params?.agentVersion === "string"
             ? params.agentVersion
@@ -2910,6 +2914,12 @@ export class SessionService {
         if (agentVersion && session?.agentVersion !== agentVersion) {
           updates.agentVersion = agentVersion;
         }
+        if (
+          typeof params?.steering === "string" &&
+          session?.steering !== params.steering
+        ) {
+          updates.steering = params.steering;
+        }
         if (session?.isCloud && session.status !== "connected") {
           updates.status = "connected";
         }
@@ -3384,22 +3394,27 @@ export class SessionService {
     // Steer: the user sent a message mid-turn and asked to fold it into the
     // running turn rather than queue it. Adapters that negotiated
     // `steering: "native"` (Claude, codex) inject at the next tool boundary;
-    // unknown adapters cancel and resend. Cloud has no real mid-turn steer
-    // (the backend only delivers messages between turns), so it falls through
-    // to the queue; compaction too.
-    if (
-      options?.steer &&
-      !session.isCloud &&
-      session.isPromptPending &&
-      !session.isCompacting
-    ) {
+    // unknown local adapters cancel and resend. Cloud sessions only enter this
+    // path after the sandbox advertises native steering; compaction still queues.
+    if (options?.steer && session.isPromptPending && !session.isCompacting) {
       if (sessionSupportsNativeSteer(session)) {
-        return this.sendSteerPrompt(session, prompt);
+        if (session.isCloud) {
+          if (session.status === "connected") {
+            return this.sendCloudPrompt(session, prompt, {
+              skipQueueGuard: true,
+              steer: true,
+            });
+          }
+        } else {
+          return this.sendSteerPrompt(session, prompt);
+        }
       }
-      await this.cancelPrompt(taskId);
-      const refreshed = this.d.store.getSessionByTaskId(taskId);
-      if (refreshed) {
-        session = refreshed;
+      if (!session.isCloud) {
+        await this.cancelPrompt(taskId);
+        const refreshed = this.d.store.getSessionByTaskId(taskId);
+        if (refreshed) {
+          session = refreshed;
+        }
       }
     }
 
@@ -3931,7 +3946,7 @@ export class SessionService {
   private async sendCloudPrompt(
     session: AgentSession,
     prompt: string | ContentBlock[],
-    options?: { skipQueueGuard?: boolean },
+    options?: { skipQueueGuard?: boolean; steer?: boolean },
   ): Promise<{ stopReason: string }> {
     const normalizedPrompt = await this.resolveCloudPrompt(prompt);
     const transport = this.d.h.getCloudPromptTransport(normalizedPrompt);
@@ -4063,19 +4078,24 @@ export class SessionService {
     if (artifactIds.length > 0) {
       params.artifact_ids = artifactIds;
     }
+    if (options?.steer) {
+      params.steer = true;
+    }
 
     const currentSessionBeforeSend =
       this.getSessionByRunId(session.taskRunId) ?? session;
     const idleEvidenceBeforeSend = this.cloudRunIdleTracker.capture(
       currentSessionBeforeSend,
     );
-    this.d.store.updateSession(session.taskRunId, {
-      isPromptPending: true,
-      promptStartedAt: Date.now(),
-      pausedDurationMs: 0,
-      agentIdleForRunId: undefined,
-    });
-    this.cloudRunIdleTracker.markBusy(currentSessionBeforeSend);
+    if (!options?.steer) {
+      this.d.store.updateSession(session.taskRunId, {
+        isPromptPending: true,
+        promptStartedAt: Date.now(),
+        pausedDurationMs: 0,
+        agentIdleForRunId: undefined,
+      });
+      this.cloudRunIdleTracker.markBusy(currentSessionBeforeSend);
+    }
     this.d.store.appendOptimisticItem(session.taskRunId, {
       type: "user_message",
       content: transport.promptText,
@@ -4088,6 +4108,7 @@ export class SessionService {
       is_initial: session.events.length === 0,
       execution_type: "cloud",
       prompt_length_chars: transport.promptText.length,
+      ...(options?.steer ? { is_steer: true } : {}),
     });
 
     try {
@@ -4105,23 +4126,25 @@ export class SessionService {
       }
 
       const commandResult = result.result as
-        | { queued?: boolean; stopReason?: string }
+        | { queued?: boolean; steered?: boolean; stopReason?: string }
         | undefined;
       const stopReason = commandResult?.queued
         ? "queued"
         : (commandResult?.stopReason ?? "end_turn");
 
       return { stopReason };
     } catch (error) {
-      this.d.store.updateSession(session.taskRunId, {
-        isPromptPending: false,
-        promptStartedAt: null,
-      });
+      if (!options?.steer) {
+        this.d.store.updateSession(session.taskRunId, {
+          isPromptPending: false,
+          promptStartedAt: null,
+        });
+      }
       this.d.store.clearTailOptimisticItems(session.taskRunId);
       const currentSessionAfterFailure = this.getSessionByRunId(
         session.taskRunId,
       );
-      if (currentSessionAfterFailure) {
+      if (currentSessionAfterFailure && !options?.steer) {
         const restoreResult = this.cloudRunIdleTracker.restoreAfterFailedSend(
           idleEvidenceBeforeSend,
           currentSessionAfterFailure,

packages/ui/src/features/sessions/components/SessionView.tsx

@@ -704,13 +704,11 @@ export function SessionView({
                             ) : null
                           }
                           messagingModeToggle={
-                            taskId && !isCloudRun ? (
+                            taskId ? (
                               <SteerQueueToggle taskId={taskId} />
                             ) : undefined
                           }
-                          onToggleMessagingMode={
-                            isCloudRun ? undefined : toggleMessagingMode
-                          }
+                          onToggleMessagingMode={toggleMessagingMode}
                           onPromptRecall={handlePromptRecall}
                           onBeforeSubmit={handleBeforeSubmit}
                           onSubmit={handleSubmit}

packages/ui/src/features/sessions/hooks/useMessagingMode.ts

@@ -19,8 +19,8 @@ export function useMessagingMode(taskId: string | undefined): MessagingMode {
  * Whether the task's session steers natively (folds a mid-turn message into the
  * running turn) versus falling back to interrupt-and-resend. Driven by the
  * adapter's negotiated `steering` capability — same decision as the host's
- * sendPrompt gate — so Claude and codex steer, while cloud
- * resend. Drives the steer label/tooltip, not whether steer is allowed.
+ * sendPrompt gate, including capability-advertising cloud sandboxes. Drives
+ * the steer label/tooltip, not whether steer is allowed.
  */
 export function useSupportsNativeSteer(taskId: string | undefined): boolean {
   return useSessionStore((s) => {

packages/ui/src/features/sessions/sessionServiceHost.test.ts

@@ -3226,7 +3226,7 @@ describe("SessionService", () => {
       );
     });
 
-    it("captures agentVersion from run_started params onto the session", async () => {
+    it("captures agent capabilities from run_started params onto the session", async () => {
       const service = getSessionService();
       const hydratedSession = createMockSession({
         taskRunId: "run-123",
@@ -3256,6 +3256,7 @@ describe("SessionService", () => {
             runId: "run-123",
             taskId: "task-123",
             agentVersion: "0.42.3",
+            steering: "native",
           },
         },
       };
@@ -3275,6 +3276,7 @@ describe("SessionService", () => {
           "run-123",
           expect.objectContaining({
             agentVersion: "0.42.3",
+            steering: "native",
             status: "connected",
           }),
         );
@@ -5472,18 +5474,50 @@ describe("SessionService", () => {
       expect(mockTrpcCloudTask.sendCommand.mutate).not.toHaveBeenCalled();
     });
 
-    it("queues a cloud steer instead of interrupting the running turn", async () => {
-      // Regression: cloud has no native mid-turn steer, so steering used to
-      // fall back to cancel-then-resend — which surfaced as a jarring user
-      // interruption. Cloud steer must now queue like a normal message and
-      // never cancel the running turn.
+    it("sends a native cloud steer immediately", async () => {
       const service = getSessionService();
       mockSessionStoreSetters.getSessionByTaskId.mockReturnValue(
         createMockSession({
           isCloud: true,
           cloudStatus: "in_progress",
           status: "connected",
           isPromptPending: true,
+          steering: "native",
+        }),
+      );
+      mockTrpcCloudTask.sendCommand.mutate.mockResolvedValue({
+        success: true,
+        result: { stopReason: "steered", steered: true },
+      });
+
+      const prompt: ContentBlock[] = [{ type: "text", text: "steer me" }];
+      const result = await service.sendPrompt("task-123", prompt, {
+        steer: true,
+      });
+
+      expect(result.stopReason).toBe("steered");
+      expect(mockSessionStoreSetters.enqueueMessage).not.toHaveBeenCalled();
+      expect(mockTrpcCloudTask.sendCommand.mutate).toHaveBeenCalledWith(
+        expect.objectContaining({
+          method: "user_message",
+          params: { content: "steer me", steer: true },
+        }),
+      );
+      expect(mockSessionStoreSetters.updateSession).not.toHaveBeenCalledWith(
+        "run-123",
+        expect.objectContaining({ isPromptPending: false }),
+      );
+    });
+
+    it("queues a cloud steer when the sandbox lacks the capability", async () => {
+      const service = getSessionService();
+      mockSessionStoreSetters.getSessionByTaskId.mockReturnValue(
+        createMockSession({
+          isCloud: true,
+          cloudStatus: "in_progress",
+          status: "connected",
+          isPromptPending: true,
+          steering: undefined,
         }),
       );