git:20260902.3a5b8ef to git:20260927.88cac0b

- - Never mention the user's emotional state. I'm here to work, NOT be psychoanalyzed by a machine.

-

- # TUI TERMINAL KNOWLEDGE (verified, don't re-derive)

-

- - ANSI emulator resize semantics ARE the product: alternate-screen buffers

- must resize like pyte/real terminals (truncate columns on width shrink,

- top-trim/pad on height change, 1:1 grid rows <-> buffer lines, clamp

- cursor) — folding stale wide lines breaks CUP row addressing = garble.

- Scrollback (normal) screen keeps folding. Oracle test: pyte dev dep.

- - Two terminal pathways by mandate: `tui/agent_terminal.py::AgentTerminal`

- (headless PTY + raw byte capture) backs the ACP terminal tool; the

- human-facing emulator (TerminalTool/EditorTerminal) is separate. A

- suspended conversation has window size 0 — never size a PTY from it.

- - Textual gotchas: `Widget.screen` is a Textual property (name pyte

- screens `pyte_screen`); `Strip` API is cell-based in Textual 8

- (`crop_extend(0, w, None)`, `adjust_cell_length`); Textual 8.2.x breaks

- on rich>=15 (uses Style internals rich dropped) — pin rich<15.

- - pyte color values are "default", ANSI names, or 6-char hex strings for

- BOTH 256-color and truecolor — never numeric palette indices (an

- all-digit hex like "281733" is truecolor).

- - A TUI only sends DIFFS: any fresh out-of-process terminal client

- (riotermjs, reconnect) sees a blank/stale screen unless the child is

- forced to full-repaint (winsize nudge: set cols-1 then cols).

- - sandbox/textual-term-toy: the terminal-in-a-column experiment + the

- riotermjs browser harness (bridge.py = PTY<->websocket; harness/ = page

- with importmap to ~/src/riotermjs dist). How to view the TUI in a

- browser: run bridge.py + `python -m http.server --directory harness`,

- open the page, screenshot via playwright-cli.

-

- # TUI STREAMING & CANCELLATION (verified, don't re-derive)

-

- - Textual has ONE message pump per app. A torrent of `session/update`

- starves key handling completely (measured: 0 Escape handlers ran while a

- mock agent blasted the pipe — starvation, not stolen bindings). Fix is to

- never render more than you can afford: `tui/acp/agent.py` coalesces chunks

- on `loop.call_later` (`STREAM_FLUSH_INTERVAL` = 30ms, early flush at 16 KB)

- and buffers wire logging O(1) instead of a task per line.

- - `session/cancel` is a notification: `jsonrpc.MethodCall.wait()` returns

- immediately when `id is None`, so awaiting it proves nothing (the old code

- always reported success). `Agent.begin_cancel()` is synchronous by contract

- and writes to stdin before returning — nothing may be awaited in front of it.

- - Turn ownership lives in `Agent.send_prompt` (`_turn_seq` / `_turn_open`), not

- in `acp_session_prompt`: prompts overlap when the user cancels and immediately

- re-prompts, and only the current turn may close it. A stale `_cancelling=True`

- silently swallows the *next* turn's updates — which is why `begin_cancel()`

- returns False when nothing is in flight.

- - `Conversation.action_cancel` claims the cancelled turn's widgets by reference

- before deferring their removal; reading `self._loading` from a deferred

- callback races the turn that replaced it and orphans its spinner.

- - Escape is bound to `cancel` with `priority=True` (priority bindings run

- App-down, before the focused widget's `_on_key`) so it survives saturation —

- and deliberately yields to a focused Terminal in `check_action`, because

- tap-tap Escape is how you leave one. The Cancel button in the prompt row is

- the mouse path; visible only while `Prompt.-streaming`.

- - TCSS: `display` accepts only `block`/`none` (no `inline`). A Button inside a

- 1-line row needs `border: none; height: 1; min-width: 0` or it adds two rows.

- - Load tests: `tests/integration/test_cancel_under_load.py` drives the real

- CrowApp against `tests/integration/mock_acp_agent.py` (env knobs

- `CROW_MOCK_TOKENS_PER_SEC` / `_CHUNKS` / `_CHUNK_CHARS` / `_IGNORE_CANCEL` /

- `_LOG`). Under load never `pilot.pause()` — it waits for a queue that never

- drains: poll on the event loop, post `events.Key` straight to the app, and use

- `Button.press()` (it refuses to post when hidden).

- - KNOWN GAP (open): per-append cost of one long `AgentResponse` is still

- superlinear (~0.24ms -> ~2.8ms over one answer) and `check_prune()` is only

- reachable from `Conversation.post()`, so a single in-flight turn is unbounded;

- fix is to roll to a new `AgentResponse` past a line cap.

-