fix: treat extension commands handled by Pi as non-turn prompts

apps/app/src/features/chat/runtime/chat-queue.test.ts

@@ -81,6 +81,17 @@ describe("Chat pending prompt", () => {
     expect(chat.store.getState().messages).toEqual([]);
   });
 
+  it("returns to ready when Pi handles a command without starting a turn", async () => {
+    const { chat, transport, attach } = makeChat();
+    await attach({});
+    transport.promptStarted = false;
+
+    await chat.prompt("/mcp");
+
+    expect(chat.store.getState().messages).toEqual([]);
+    expect(chat.store.getState().status).toBe("ready");
+  });
+
   it("keeps the queue empty when a follow-up races to a real prompt", async () => {
     const { chat, transport, attach, live } = makeChat();
     await attach({});

apps/app/src/features/chat/runtime/chat.ts

@@ -701,6 +701,9 @@ export class Chat {
       });
       if (!receipt.started) {
         this.#state.messages = this.#state.messages.filter((message) => message.id !== messageId);
+        // No turn started for this prompt (queued into a running turn, or an
+        // extension command handled it). A running turn re-stamps the phase.
+        if (this.#state.status === "submitted") this.#setStatus("ready");
       }
     } catch (promptError) {
       this.#state.error =

packages/server/src/harness/pi/process.ts

@@ -535,7 +535,7 @@ export const makePiProcessWithDependencies = <R>(
                   if (before._tag === "Idle") yield* drainQueue(session.chunks);
 
                   // Stock Pi before 0.99 omits `data`. 0.99 returns `{ disposition }`.
-                  // pie-pi-process still returns `{ started }`.
+                  // pie-pi-process returns `{ started, disposition }`.
                   const admission = yield* restore(
                     session.transport.command<
                       { readonly started?: boolean; readonly disposition?: string } | undefined

packages/server/src/harness/pi/rpc/rpc-mode.ts

@@ -444,7 +444,8 @@ export async function runRpcMode(runtimeHost: AgentSessionRuntime): Promise<neve
               preflightSucceeded = true;
               // 0.99 reports disposition instead of a boolean. isStreaming is
               // already true for a prompt that just started, so it cannot mean
-              // "queued".
+              // "queued". "handled" (an extension command consumed the input)
+              // starts no turn, so it is forwarded for the host to tell apart.
               output(
                 success(id, "prompt", {
                   started: disposition === "started",

packages/server/test/harness/pi/agent.test.ts

@@ -239,6 +239,10 @@ layer(NodeServices.layer)("PiAgent", (it) => {
       assert.equal(prompt.started, false);
       const chunks = yield* Stream.runCollect(prompt.output);
       assert.equal(Array.from(chunks).length, 0);
+
+      const next = yield* agent.session.prompt({ sessionId, text: "ping" });
+      assert.equal(next.started, true);
+      assert.equal(Array.from(yield* Stream.runCollect(next.output)).at(-1)?.type, "finish");
       yield* agent.session.abort(sessionId);
     }),
   );