Entered-prompt Pi multi-round trial

Question and scope

Can a user enter successive prompts into one real Pi conversation, cancel a streamed answer, and continue while earlier terminal history remains available?

This extends the finite Pi session trial, reusing its event mapping, the SDK, and the experimental terminal host. It exercises Context lifecycle across turns through a separate plain-text frontend.

Stage-three completion boundary

This stage delivers a finite, entered-prompt Pi frontend paired with our experimental terminal. Its acceptance checks are retained multi-round model context; continuation after assistant/tool cancellation; old reading, selection/copy and search during subsequent output; fail-stop and cleanup; and a separately recorded, deliberately initiated subscription trial. The 2026-09-21 checkpoint below records the completed acceptance checks.

Run

From the repository root, with the existing Node 24+/pnpm dependencies:

pnpm prototype:pi-multi

Open http://127.0.0.1:4178/, connect, wait for [ready 1/5], enter a prompt, and choose Send prompt. This default uses a deterministic local model provider through the actual pinned Pi 0.86.1 SDK: it reads the fixed sample, echoes the entered prompt, and includes the preceding prompt if one exists. It runs locally without model requests or credentials. For generated answers to arbitrary prompts, use the opt-in live source below.

Cancel current turn retains whatever partial response Pi has produced and, when Pi settles without reporting an error, permits another prompt after the next ready marker. End session cancels any active turn and exits after cleanup; Disconnect immediately closes the transport and is not a successful-completion claim. Search, native scrolling, selection, and copy use the existing experimental host. Reload for a fresh conversation; the form draft stays after sending because transport delivery does not mean the application accepted it.

Only the form supplies prompts; terminal keystrokes are not forwarded. Busy prompts are rejected with a notice, not queued or used as steering messages. Application controls are newline-delimited JSON on ordinary stdin after protocol-response decoding; they are not new protocol Messages.

Optional live source

pnpm prototype:pi-multi-live

This selects the existing Pi OpenAI Codex OAuth source and explicit SSE model transport. The login and model-selection rules still apply. Each accepted prompt sends its text, retained conversation, tool definition, and any sample result to OpenAI and consumes subscription allowance. Do not enter secrets. No project files or shell tools are exposed. The only tool reads the repository’s fixed fixtures/sample.txt; it cannot choose paths. Automatic fixture checks are disabled in live mode. An optional, explicitly armed one-shot helper clicks Cancel after visible assistant text; it never starts a prompt. A four-prompt live checkpoint records tool use, retained context, assistant cancellation, a subsequent successful prompt, search, and exit.

Both commands share port 4178 with the other PTY examples; run one at a time. Stop the server with Ctrl+C. Builds require the development host and its injected connection token to run; they are not standalone deployments.

Lifecycle and limits

  • One in-memory Pi session retains model conversation across turns. Each turn gets a fresh protocol Context and event adapter; normal completion/cancellation closes that Context explicitly while leaving its display history available. Reusing local Block names in a new Context does not reuse their identity.

  • At most five submitted turns, including cancellations, per connection; 2,000 UTF-16 units per prompt; ten sample reads per Pi session. A cancellation before Pi starts the prompt can leave an empty closed Context and no model conversation entry. These are local trial policies, not negotiated limits.

  • A turn has a 60-second cooperative deadline, and the application a ten-minute deadline including idle time. The browser closes after ten minutes plus ten seconds. Cancellation/deadlines request Pi abort; this does not prove a bound for an unresponsive provider or tool.

  • Existing per-turn adapter/event/content and output budgets apply, together with host Session/pending-input limits. Five turns is not a bound on total process memory, live tokens, or cost. Automatic retries and compaction remain disabled; model context-window exhaustion is not recovered automatically.

  • A model, protocol, transport, parsing, or resource failure stops this connection. It does not start a fallback UI, reopen failed Contexts, retry, or report a completed turn. EOF may close an incomplete display Context; closure alone is not evidence of successful completion.

Cancellation at a tool boundary

The initial implementation stopped after cancelling the sample tool: Pi tried to prepare another model request with an already-aborted signal, and its lazyStream setup handling classified that exception as an ordinary assistant error in the pinned local-provider setup.

The trial source now installs Pi’s public shouldStopAfterTurn hook to stop when the active run signal is aborted. The agent loop calls it after settling tool results, before the next model turn. The cancelled tool’s error result stays visible, the round is marked aborted, its Context closes, and the next user prompt can run. The hook uses the abort signal rather than matching returned error text. Genuine model errors, including ones racing with cancellation, still fail the connection.

Files

File

Responsibility

application.ts

Own negotiated transport, ready/busy/turn loop, deadlines, and cleanup.

commands.ts

Bound and parse form commands independently of protocol replies.

provider.ts

Local deterministic responses using actual Pi conversation/tool inputs.

main.ts, main-live.ts

Compose the fixture or explicitly selected subscription source.

browser.ts, index.html

Enter prompts and send cancel/end controls through the reused host.

vite.config.ts, page-mode.ts

Select one fixed child, inject source labels, and fail closed if live fixture-control removal cannot be applied.

checks.ts, checks.html

Repeat the multi-round local-provider browser scenarios.

native-checks.ts

Inspect reading position, selection/copy, both cancellation boundaries, and finite exit in the supporting browser host.

../multi-round.test.ts

Real Pi plus in-process protocol/Session lifecycle and input checks.

../multi-round-page.test.ts

Verify live labels and removal of both fixture-test entry points.

live-checkpoint.md

Expected-versus-observed record of deliberate subscription calls.

Verification

pnpm typecheck
pnpm test:pi-session
pnpm test
pnpm build:pi-multi

While serving the default fixture, open /checks.html and choose Run checks. Recorded on 2026-09-21 using Windows bundled ConPTY and experimental browser xterm, the three grouped checks passed:

  1. Two entered prompts share Pi conversation state; each display Context closes.

  2. Cancelling the third streamed answer retains partial content; the fourth prompt completes in the same Pi session, with the cancelled user turn retained.

  3. Earlier input remains searchable; ending while idle confirms child exit zero and all four Contexts explicitly closed before EOF.

On a fresh main page in fixture mode, Run native and cancellation checks also passed four grouped checks through real ConPTY and xterm:

  1. Reading an old marker above the bottom: its screen row, selection, and copied text remain unchanged during the second turn’s stream and after completion.

  2. Cancelling the sample tool in the third turn settles its result and returns to a ready state with that Context closed.

  3. Cancelling assistant streaming in the fourth turn still permits the fifth prompt to complete; the five-turn limit then exits 0 with five closed Contexts.

  4. Old content remains searchable and copyable after exit.

At this checkpoint, type checking, 52 focused Pi Node tests, all 276 Node tests, and the multi-round, single-round Pi, and terminal-host browser builds passed. The original two single-round Pi browser scenarios were rerun and passed. The live page’s warning and disabled automatic-check page were separately checked before the finite subscription run. Builds retain the existing xterm bundle-size warning.

The Node checks additionally exercise UTF-8 split input, malformed/oversized commands, busy-prompt rejection, immediate cancellation, active/idle quit, second-turn model failure, terminal rejection, EOF, deadlines, unsupported negotiation, output-budget rejection, and input-mode/listener cleanup. They also exercise tool cancellation followed by another turn. The browser checks are separate from pnpm test. They inspect terminal/Session state and search through the real PTY path. The native runner uses public xterm selection/scroll methods and the real copy handler with an in-memory clipboard sink; it does not test a physical mouse drag, the OS clipboard, or long-duration usability. Wider native-capability evidence remains in the host’s separate suites.

This trial keeps a 40-by-8 viewport and one in-memory conversation on Windows bundled ConPTY. Resize, capacity reclamation, broader Unicode interaction, backpressure, and reconnect behavior need separate checks. Integrating Pi’s stock editor/extensions, rich Markdown, persistent sessions, or other terminal hosts remains follow-up work. The host uses pinned private xterm interfaces and experimental OSC 9002.