# Terminal Query Authority

Status: Phase 5 of the terminal model/view architecture. Builds on
[`terminal-model-view-contract.md`](./terminal-model-view-contract.md) (this
phase **amends invariant 6**),
[`terminal-side-effect-authority.md`](./terminal-side-effect-authority.md)
(Phase 3), and the Phase-4 hidden-delivery gate
(`src/main/ipc/pty-hidden-delivery-gate.ts`).

## Problem

Phase 4 drops renderer-bound bytes for hidden-gated PTYs after model ingestion
(`src/main/ipc/pty.ts:1417,1506`, `src/main/ssh/ssh-relay-session.ts:931`).
Queries embedded in dropped bytes get no reply: DA1 (ConPTY 1.22+ blocks
waiting for it — `terminal-conpty-device-attributes.ts:22`), CPR probes hang
TUIs, OSC 10/11 leaves `claude /theme` blind while hidden. The pre-Phase-4
hidden skip latch had the same hole (only mode 2031 and the 10s codex startup
window answered), so this is not a regression — it is the long-standing gap
this phase closes.

Contract invariant 6 ("the model must never answer queries") was written
against a real bug: the daemon emulator replying ahead of the renderer with
default-xterm values (the OSC-11 default-black-background race,
`headless-emulator.ts:82-93`, pinned by `session.test.ts:163-187`). The danger
was never "the model answers" — it was **two answerers for the same bytes**,
one of them with wrong values. Phase 5 keeps the singularity and fixes the
values.

## Decision: the delivery decision is the reply decision

Main answers a query **iff main dropped the chunk that carried it**. The same
per-chunk hidden-gate predicate (`shouldDropHiddenRendererPtyData`) that
decides renderer delivery decides reply ownership, evaluated once,
synchronously, at ingestion:

- Visible/unmarked PTY → chunk delivered → renderer xterm auto-replies via
  `Terminal.onData` → `transport.sendInput`, unchanged.
- Hidden-marked, no delivery interest → chunk dropped → main answers from the
  runtime headless emulator, via the provider input path (`provider.write`,
  same path as `pty:write`; daemon shell-ready write gating and the SSH relay
  write apply unchanged).
- Replayed/seeded/snapshot bytes → answered by no one (replay guards on both
  sides).

This is structurally exactly-one-responder: a chunk is delivered or dropped,
never both, and each side only answers bytes it actually parsed live. The
mark/unmark ordering, unhide-before-restore, and restore-marker IPC all exist
from Phase 4 and are reused, not duplicated.

Rejected alternatives:

- **Fact-based renderer replies per query class** (the mode-2031 pattern
  generalized): needs a main-side detection grammar per query, a fact round
  trip per reply, and the renderer cannot answer CPR/DECRPM anyway — the
  emulator is the only state for a hidden pane. The 2031 fact stays because it
  is subscription registration, not a state query.
- **Emulator always answers**: re-creates the OSC-11 double-reply race for
  visible panes. Never.

## Mechanism: forwarded emulator onData, not a new grammar

`HeadlessEmulator` gains `onData` wiring behind a per-write capture flag.
For static and model-state queries, xterm core **is** the query grammar: the
runtime emulator runs the same xterm version with equivalent options as the
renderer pane, so main's reply set equals the visible renderer's by
construction — verified empirically against the bundled headless build:
DA1/DA2, DSR 5n, CPR, DECRPM (including unknown-mode `0`), DECRQSS (including
DECSCUSR from cursor options), XTVERSION, kitty `CSI ? u` all reply; XTWINOPS
(`windowOptions` stays default-off) and XTGETTCAP stay silent, matching
visible behavior today. The headless build has **no theme service**: OSC
4/10/11/12 queries and DSR ?996n return nothing even with the `theme` option
set, so the view-attribute class is answered by responder-registered parser
handlers instead (below) — never by core defaults.

Forwarding predicate, captured per chunk in `OrcaRuntimeService.onPtyData` and
attached to the emulator `writeChain` link (the mark can flip between
ingestion and an async write; the decision must not be re-read at reply time):

1. gate enabled (`terminalMainSideEffectAuthority` and
   `terminalHiddenDeliveryGate` both on) AND new kill switch
   `terminalModelQueryAuthority !== false`;
2. the chunk was hidden-dropped for this PTY (`shouldDropHiddenRendererPtyData`
   — same module state, same tick as the drop sites);
3. the write is live PTY data — never `seedHeadlessTerminal`,
   `maybeHydrateHeadlessFromRenderer`, option pushes, or any snapshot replay
   (main-side replay guard, mirror of the renderer's `replay-guard.ts`);
4. no remote view subscriber is attached to the PTY (runtime terminal-RPC
   subscriber records / `mobileSubscribers`): a mobile/web/remote-desktop
   xterm receiving the multiplexed stream answers with view authority, exactly
   like a visible local pane. Read-only consumers (CLI reads, automation
   observers) do not suppress — they also do not answer; that bounded
   no-reply case matches today's behavior.

Everything the emulator emits outside a forwarding window is discarded, which
also swallows unsolicited core emissions (e.g. native 997 color-scheme pushes
triggered by option mutations).

## Reply classes

| Class | Queries | Answer source |
| --- | --- | --- |
| Static | DA1 `CSI c` (ConPTY override below), DA2, DSR 5n, XTVERSION, DECRQM unknown → `0`, kitty `CSI ? u` | xterm core constants + kitty flag state |
| Model-state | CPR `6n`/`?6n`, DECRPM mode table (?1 ?6 ?7 ?25 mouse ?1004 ?1006 ?1016 ?1049 ?2004 ?2026, insert), DECRQSS DECSTBM/DECSCA/SGR, kitty flags | emulator buffer/mode state — for a hidden pane it is the only state, hence authoritative |
| View-attribute | OSC 4/10/11/12 `;?` queries, DSR ?996n | responder parser handlers + renderer attribute push (below); **silent until first push** |
| View-attribute (via options) | DECRQSS DECSCUSR, DECRQM 12 | xterm core, from pushed `cursorStyle`/`cursorBlink` emulator options |
| Silent | XTWINOPS, XTGETTCAP, ?15n/?25n/?26n/?53n | nobody, visible or hidden |
| Mode 2031 | DECSET 2031 subscribe | unchanged in Phase 5: main emits the `2031-subscribe` fact, the renderer replies (`pty-connection.ts:1627`, parked watcher fact callback). Emulator-native 2031/997 output is suppressed by the forwarding guard |

### View-attribute bridge

New renderer→main push, `pty:terminalViewAttributes` — one global snapshot,
not per-PTY: the composed terminal `ITheme` (from
`applyTerminalAppearanceToPanes`, `terminal-appearance.ts:211-232`),
`terminalCursorStyle`, `terminalCursorBlink`, and the resolved color-scheme
mode (`resolveTerminalColorSchemeMode` — the same source as the existing
hidden 2031 reply). Pushed on renderer startup and on every theme/settings
apply.

Main consumes it two ways:

- `cursorStyle`/`cursorBlink` are applied to every runtime emulator's options
  inside the replay guard; xterm core then answers DECRQSS DECSCUSR and
  DECRQM 12 with renderer-true values (verified working headless).
- Palette and color-scheme replies come from responder-registered parser
  handlers on the emulator (`registerOscHandler` 4/10/11/12,
  `registerCsiHandler` for DSR ?996n), because the headless core cannot
  answer them. The OSC handlers see SET payloads too, so runtime OSC
  4/10/11/12 mutations (and 104/110/111/112 resets) from the byte stream are
  tracked per PTY and layered over the pushed base palette — matching what
  the renderer's theme service reports for a visible pane.

Staleness rules: replies use the last push; a theme flip is stale for at most
one IPC hop (subscribed TUIs are corrected by the 2031/997 flip push).
**Before the first push main answers no view-attribute query** — a fabricated
default would resurrect the default-black OSC-11 bug; silence is the
documented hidden status quo.

### Kitty keyboard flags

Enable `vtExtensions.kittyKeyboard: true` in `HeadlessEmulator`, matching
`buildDefaultTerminalOptions` (`pane-terminal-options.ts:49`). Risk is low:
for the write-only daemon use, keyboard state never alters serialization; the
change only makes the emulator parse `CSI =/>/< u` pushes instead of ignoring
them, and lets the responder answer `CSI ? u` with the flags the hidden app
actually pushed. Snapshot parity: add `kittyKeyboardFlags` to `TerminalModes`
for emulator re-seed parity only. `rehydrateSequences` must **not** push kitty
flags into a renderer xterm — `POST_REPLAY_REATTACH_RESET`'s deliberate kitty
reset (stale CSI-u Ctrl+C hazard, `terminal-replay-cursor-state.test.ts`)
stays authoritative. A re-seeded emulator that lost flags answers `?0u`;
protocol-conformant programs re-push.

### ConPTY DA1 variant

The provider kind is known main-side: mirror `isLocalNativeWindowsPty`
(`windows-pty-compatibility.ts:48`) from the spawn record (local/daemon
provider, `win32`, not WSL). For such PTYs register a CSI `c` override on the
emulator parser (the main-side twin of
`installConptyDeviceAttributesHandler`) replying `CSI ?61;4c`, still gated by
the forwarding predicate. ConPTY blocking on a missing DA1 is a spawn-time
hazard; spawn-time ownership is deterministic (see races below).

## Suppression: when main never replies

- Visible or unmarked PTY (chunk was delivered).
- Renderer delivery interest registered (chunk was delivered to a sidecar).
- Codex startup window active — the renderer never marks the PTY hidden while
  the window runs (`pty-connection.ts:2259-2261`), so the gate predicate is
  structurally false; the live xterm answers startup probes.
- Remote-runtime (`remote:`) PTYs — never markable
  (`isHiddenDeliveryGateManagedPty`), bytes never transit local main.
- Remote view subscriber attached (mobile/web/remote desktop owns replies).
- Seed/hydration/snapshot writes into the emulator, and option pushes.
- Kill switches off — no marks exist, and `terminalModelQueryAuthority` is an
  independent off switch for the responder alone.
- The **daemon** emulator: never, under any setting. The responder lives in
  main's runtime only; `session.test.ts:163-187` stays pinned verbatim.

## Transition races

Worst cases, per direction:

- **visible→hidden**: chunks delivered between the visibility flip and the
  mark landing in main are hidden-skipped by the renderer write path without
  query scanning. No reply, no duplicate — identical to the pre-Phase-4 hidden
  skip behavior, bounded by one renderer→main IPC hop. After the mark lands,
  main answers everything it drops.
- **hidden→visible**: unmark consumes the drop latch and emits the restore
  marker; the snapshot replay is replay-guarded, so queries main already
  answered are never re-answered from the snapshot; post-unmark live chunks
  are answered by xterm once (restore-queued live chunks reply late, not
  twice).
- **Split queries across the drop/deliver boundary**: neither parser saw the
  whole sequence → no reply; the restore marker resets renderer cross-chunk
  state and replay hygiene resets the parser. At-most-once holds.

Safe-side rule per class: duplicates are structurally impossible (one decision
point per chunk); where the race costs anything it costs a missing reply.
That is acceptable for state queries (DSR/CPR/DECRPM — TUIs re-probe or
tolerate silence, as they did for every hidden pane before this phase). The
one blocking-on-no-reply sequence, ConPTY DA1, only fires at spawn, where
ownership is deterministic: visible pane, startup window (renderer), or
marked-at-spawn (main). It cannot land in the flip gap.

## Invariants

1. Exactly one party may answer any query, chosen by the chunk's delivery
   decision: delivered → the consuming live view's xterm; dropped → main's
   model responder; replayed/seeded → no one. The decision is captured once,
   synchronously, at ingestion.
2. Main answers only from live PTY bytes parsed by the runtime emulator —
   never from snapshot, seed, hydration, or option-push writes.
3. View-attribute answers are renderer-true or absent: no reply is ever
   fabricated from emulator defaults (the OSC-11 lesson).
4. The daemon emulator stays write-only; daemon subprocess query writes stay
   zero (`session.test.ts` pins are permanent).
5. Reply parity is structural for static and model-state classes: same xterm
   core, equivalent options, no hand-rolled grammar — the only overrides are
   the documented ConPTY DA1 variant and the view-attribute parser handlers
   the headless core cannot serve.
6. Remote views keep view authority; main yields whenever a remote view
   subscriber is attached.

**Contract amendment** — `terminal-model-view-contract.md` invariant 6 is
replaced by:

> 6. Terminal query authority is singular and structural: the party that
>    writes a chunk into a live terminal answers its queries. Visible renderer
>    and remote views keep xterm authority. Chunks dropped by the
>    hidden-delivery gate are answered exactly once by the main model
>    responder, from runtime-emulator state plus renderer-pushed view
>    attributes. Replayed, seeded, or snapshot bytes are answered by no one.
>    The daemon emulator never answers.

The contract's test bullet "headless tracking does not answer DA, DSR, OSC 11,
or theme-sensitive queries" splits into: daemon emulator never answers
(unchanged pins) / runtime responder answers only hidden-dropped chunks. The
side-effect authority matrix row "DECSET 2031 reply — query authority stays
with the view (contract invariant 6)" gains a pointer here; its reply path is
otherwise untouched in this phase.

## Test strategy

- Responder unit tests beside `orca-runtime.test.ts`: marked vs unmarked vs
  interest-suppressed; each reply class; seed/hydrate silence; remote-
  subscriber suppression; ConPTY DA1 variant; kill-switch off; mark flip
  between ingestion and async emulator write (captured decision wins).
- Parity harness: shared query byte fixtures through a renderer-configured
  xterm (onData capture) and through the responder; assert byte-identical
  replies for static + model-state classes, and for view-attribute classes
  after an attribute push.
- `session.test.ts:163-187`: assertions stay; the comment is updated to name
  the main responder (not "the renderer") as the hidden answerer.
- E2E: hidden `claude /theme` reports the configured theme; hidden TUI
  blocked on CPR/DA unblocks while gated; reveal shows no stray reply
  fragments (`?1;2c`, `rgb:` …) on the prompt; Windows ConPTY golden and
  `terminal-hidden-view-parking.spec.ts` stay green.

## Cut-offs (stacked, independently mergeable)

1. **Responder core.** Emulator onData wiring + per-write capture + main
   replay guard; kitty flag enable (+ `TerminalModes.kittyKeyboardFlags`);
   static + model-state classes; ConPTY DA1 override; remote-subscriber
   suppression; `terminalModelQueryAuthority` switch; unit + parity tests.
   Main-only — no renderer change. Ships the DA1/CPR/DECRPM unblock.
2. **View-attribute bridge.** `pty:terminalViewAttributes` push, cursor
   option application under the guard, responder OSC/DSR parser handlers with
   per-PTY palette-mutation tracking, silent-until-push rule, `/theme` e2e.
3. **Contract alignment.** Invariant-6 amendment in the contract doc, test
   bullet split, `session.test.ts` comment, side-effect matrix pointer, and
   the Phase 6 prerequisites below recorded as accepted.

## What Phase 6 (delete skip grammar + startup window) requires from this design

- **Mark-before-first-byte**: panes spawned without a visible view must be
  hidden-marked at spawn (spawn-record flag, not a renderer round trip) so
  startup queries — including ConPTY's blocking DA1 and codex startup probes —
  are main-owned from byte zero once the 10s window is gone.
- **Attributes before spawn**: the renderer must push view attributes at app
  start, before any hidden spawn, or spawn-time view-attribute queries fall
  into the silent-until-push rule.
- **Daemon shell-ready write gating** queues responder replies until the
  ready marker; spawn-time replies on Windows daemon PTYs need explicit
  validation before the window is removed.
- With the skip grammar deleted, every chunk is either written to a live
  xterm or dropped — the delivered-but-skipped no-reply gap disappears and
  the only remaining loss window is the mark IPC race.
- **2031 consolidation** (optional follow-up): move the subscription registry
  into the responder (the headless core cannot serve 997 pushes any more than
  it can ?996n) and push 997 flips from the attribute cache, retiring the
  `2031-subscribe` fact reply, the parked responder, and the parked-tab
  theme-flip gap.