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

[oxwen11]

Requirement

Sending an extension slash command such as /mcp or /mcp login <server> in Pie fails with "Model request failed … Pi queued a prompt without an active server turn". Found while verifying #433, and it reproduced on main at 18ba5813.

Regression from #426. Pi reports a prompt disposition (started | queued | handled). rpc-mode.ts reduced that to started: disposition === "started", so a prompt an extension command consumed (handled) looked like a queued prompt with no active turn.

Since this opened, #429 forwarded disposition and stopped failing a queued prompt that has no server turn. The client still stayed on the optimistic submitted status, so the composer kept waiting.

Expected behavior

• An extension command that Pi handles without starting a turn succeeds:
  • there is no error;
  • the optimistic bubble is removed;
  • the composer returns to idle;
  • the next prompt starts a normal turn.
• A prompt Pi queued while the server has no turn is streamed, as on main after fix(server): stream a prompt Pi queued after the server turn ended #429. It is not an AgentOperationError.

Changes and risks

• apps/app chat.ts: when a receipt is not started and the status is still the optimistic submitted, the status resets to ready. A running turn re-stamps the phase from its events.

• Server admission already returns a non-started receipt for disposition: "handled" (fix(server): stream a prompt Pi queued after the server turn ended #429). This merge keeps that, and keeps fix(server): stream a prompt Pi queued after the server turn ended #429's attach-and-stream for a queued prompt with no server turn. The branch's prompt-admission-state error for that case is gone.

• Prompt RPC disposition stays optional, matching main. Pi 1.0.2 still reports started | queued | handled; an extension command still calls preflightResult("handled") and returns without a turn. chore: stop passing --no-extensions to the Pi child #443 loads those commands in the Pi child, so this path is live.

• Out of scope (would need contract changes):

  • Extension command output (notify) is still not shown in Pie.
  • Interactive UI requests outside a turn are still declined.

  So /mcp runs without error, but its output is not visible yet.

Verification

Tested revision: 84dbc549 (merge of origin/main 6bb30797 into ffb36b64).

• pnpm --filter @getpie/server exec vitest run test/harness/pi/agent.test.ts: 24 passed. The handled-prompt case checks an empty non-started receipt and that the next prompt starts and finishes.
• pnpm --filter @getpie/app exec vitest run src/features/chat/runtime/chat-queue.test.ts: 14 passed. The handled command returns status to ready.
• pnpm check passed.
• Pi 1.0.2 AgentSession.prompt still reports handled for an extension command and does not start a turn (installed package). Not re-run: the live web /mcp pass from ffb36b64.

[oxwen11]

Runtime evidence (pie-verify web, isolated PIE_HOME / PI_CODING_AGENT_DIR, fake e2e provider).

Before (main 18ba581): before-typed-mcp.png, then before-sent-mcp-error.png (error card). Video: the before recording-002.webm shows typing and sending /mcp.
After (ffb36b64): after-typed-mcp.png, then after-sent-mcp-no-error.png (no error, composer idle), then after-followup-prompt-replies.png (hello after mcp gets the fake reply). Video: the after recording-002.webm shows the same steps.

recording-002.webm

recording-002.webm

[github-actions]

React Doctor found no new issues. 🎉

_{Reviewed by React Doctor for commit 03cfced.}

[pkg-pr-new]

npx https://pkg.pr.new/oxwen11/pie/@getpie/cli@438

commit: 03cfced

[oxwen11]

auto-merge: no

head ffb36b644d6e — required CI green (Check, react-doctor, both Publish @getpie/cli preview, Continuous Releases, React Doctor), but fails the gate and the exclusions:

• Gate: mergeable=CONFLICTING / mergeStateStatus=DIRTY against main (f6912c31e83b, fix(server): stream a prompt Pi queued after the server turn ended #429), so it is not MERGEABLE.
• Exclusion (non-presentational fix / product behavior): packages/server/src/harness/pi/rpc/rpc-mode.ts and rpc-types.ts add a disposition field to the prompt RPC response; packages/server/src/harness/pi/process.ts returns an empty, non-started turn when disposition === "handled"; apps/app/src/features/chat/runtime/chat.ts flips status submitted → ready when no turn starts. This changes runtime prompt/turn control flow on both server and app.
• Exclusion (tests that also change product control flow): the new tests in chat-queue.test.ts and agent.test.ts ship together with the control-flow changes above.

No allowed group (docs/tooling, lint/format, UI presentation) covers these hunks. Needs human review; rebase onto main to clear the conflict. Not merged.

[oxwen11]

Merged origin/main (6bb30797) into this branch as 84dbc549. No rebase, no force push. PR is not merged.

Conflicts were only in the prompt-admission path (process.ts, rpc-mode.ts, rpc-types.ts, agent.test.ts). chat.ts auto-merged.

Resolution:

• Kept the client reset to ready when a non-started receipt leaves status submitted. That is what stops an extension command from leaving the composer waiting. main still lacked it.
• Kept fix(server): stream a prompt Pi queued after the server turn ended #429's server behavior: handled returns a non-started empty receipt; a prompt Pi queued with no server turn is streamed instead of prompt-admission-state. The branch's error for that queued case is dropped.
• disposition stays optional, matching main.
• Pi 1.0.2 still uses started | queued | handled. An extension command still calls preflightResult("handled") and returns without a turn. chore: stop passing --no-extensions to the Pi child #443 loads user extensions, so that path is now live; no extra change was needed for it. feat(server): background long bash commands after 60 seconds #390 auto-merged and does not touch this receipt.

Checks: server agent.test.ts 24 passed (handled prompt, then the next prompt starts); chat-queue.test.ts 14 passed; pnpm check passed. Live web /mcp was not re-run.

[oxwen11]

Review + verification record — #438

• Head: 03cfced49d256bcd457d22aa481befd881d20004, base: 7b4d86b1bd8caa1fb3d6c0c5e883b7e29930cc7f (trusted rules from base)
• Required CI on this head: Check, react-doctor, both Publish @getpie/cli preview jobs — all pass.

Conclusion: verified, merging.

Review

• chat.ts: when Pi returns a receipt with started: false, the client now drops the optimistic message and moves the optimistic submitted state back to ready. A turn that really starts still sets status from stream events, so the reset can't hide a running turn.
• rpc-mode.ts / process.ts: comment-only changes.
• New tests:
  • chat-queue.test.ts covers the not-started receipt returning to ready.
  • agent.test.ts checks that a prompt after a handled command still starts and finishes.
• No trust boundary, persistence or contract changes.

Independent verification

Clean worktrees, isolated PIE_HOME, real Pi with the operator's model.

• Tests: server agent.test.ts 24/24, app chat-queue.test.ts 14/14.
• Web, before (main 7b4d86b1):
  • Steps: prompt → answer → send /mcp.
  • At 6 s the composer is still showing Stop generating. It only went back to idle at about 26 s.
• Web, after (PR head):
  • Steps: prompt → answer → send /mcp.
  • The composer is idle at 1 s and at 6 s, with no error. The next prompt AFTER-MCP-438 is answered normally.
• Desktop, after (PR head, Electron dev):
  • Steps: same flow.
  • The composer is idle at 1 s and at 6 s, and the next prompt AFTER-MCP-DESKTOP is answered.
• The slash-command suggestion list is masked in the videos because it lists the operator's local skills.

Gaps / notes

• On first launch, the Desktop dev renderer sat on the "Starting Pie" splash until one reload. This looks like Vite's first-compile timing in dev mode and is unrelated to this diff. It was not investigated further.
• No Desktop "before" run. The changed code is the shared SPA chat runtime, and the bug is demonstrated in the Web before run.

Re-review is warranted if the receipt or status handling in chat.ts changes again.

438-before-main.webm

438-after-pr.webm

438-desktop-pr.webm

[oxwen11]

Merged as 9960a7b (squash of verified head 03cfced; record: #438 (comment)).