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phase: 08_kiosk_page
**Phase 08 final verification pass — complete, all green.**

**Verified (all 5 tasks already implemented):**
- `static/wall.js` (`createWall` + `installWallKeys`), `kiosk.html`/`kiosk.js`, `GET /kiosk` route — guards: no `$("#…")` in wall.js, one keydown listener, kiosk ids no-collision across 3 pages, no audio field in `arrange`, no header/share link in markup, address gate covers `/kiosk`
- Cross-page e2e: arrival-arrangement, keypress-on-one-display moves the other (asserted on the second display's decoded moving pixels), dead mirror → `data-layout="wall"` on both, `followers` count, pointer-free meta-test

**Gates (exact outcomes):**
- `uv run ruff check . && uv run ruff format --check .` — passed
- `uv run pyright` — 0 errors
- `uv run pytest` — 341 passed, 5 skipped (realdisplay-gated), 96s
- `MIRROR_REALDISPLAY=1 uv run pytest -m realdisplay` — 4 passed, 1 skipped (documented: host has no audio source for real capture)
- Coverage 96% (>90%); only warning is a starlette/httpx third-party deprecation

**Completion criteria:** all 9 ✅ — e2e green incl. `test_kiosk_layout.py` (the one e2e diff is the phase-mandated address-gate extension to `/kiosk`; assertion logic untouched), full suite 100% passing, README documents `/kiosk`, PLAN.md untouched.

**Documentation:**
- README: fixed the Kiosk-client section that implied the display box is permanently pointed at `/watch` — now states the display page is `/kiosk` with the runbook's one-line re-point (installer default still `/watch` this phase, per docs). Rest of README verified against code (routes, config table, CLI flag, presets, key table) — consistent.
- AGENTS.md: fixed 2 stale statements — CDN test moved to `TestPages` (was `TestClientScripts`), suite runtime ~50s → ~95s. No content added.

**Notable:** PLAN.md §6 says "per-leg `maxBitrate` cap (default 12 Mbit/s)" but code/README default is 25 Mbit/s — pre-existing, left untouched (locked file; flagged for a user decision).

**Next pending phase:** `09_wall_remote_page`.
2026-11-03 22:38:22 -05:00

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# mirror — Agent Operating Rules
**Read `.agents/PLAN.md` before touching anything here.** It holds the locked
architectural decisions; this file holds the rules for working inside them.
`mirror` is browser-only screen mirroring for a local network: `/mirror` shares a
window/screen/tab via the OS-native picker, `/watch` shows every live mirror and
lets anyone take one fullscreen. Media flows peer-to-peer over WebRTC; the server
is a roster and a signaling relay. Linux is the reference platform.
---
## 1. The order of reading
1. `.agents/PLAN.md` — architecture, locked anchors, verification ladder.
2. `README.md` — the user-facing contract.
3. `SECURITY.md` — why there is no authentication, and what that costs.
4. `src/mirror/registry.py` — the whole policy lives here. Read it before
changing behavior; it is short and it is the product.
## 2. Phased execution
```
.agents/
├── PLAN.md ← locked design (do not edit without an explicit decision)
└── phases/
├── todo/ ← pending phases: NN_name/00_phase.md + NN_task.md
└── complete/ ← finished phases, read-only history
```
* New work enters through the **`phase-authoring` skill**, never as a direct
implementation of a vague request.
* Phases run through the **`phased-execution` skill**.
* Never edit anything in `phases/complete/`. Ask before editing `phases/todo/`.
* Never edit `PLAN.md` unless the user explicitly authorises a change to a locked
decision, and record the reason in the same change.
* A phase is not done until every gate in §4 passes.
## 3. Locked decisions that are easy to break by accident
| Rule | Why it exists |
|---|---|
| **No external assets.** No CDN, remote font, remote icon, `@import`, or analytics | LAN/offline correctness. `tests/test_app.py::TestPages::test_nothing_is_loaded_from_a_cdn` fails the build if you add one |
| **No framework, no bundler** in `src/mirror/static/` | Four pages and one WebSocket. `node --check` is the entire frontend toolchain |
| **Media never passes through the server** | The server relays JSON only. Anything that puts frames in the Python process violates A3 |
| **`Registry` stays pure** — no sockets, no FastAPI, no `await` | It returns `list[Envelope]`. Transport lives in `Hub`. This is why the policy has 100%-ish unit coverage |
| **camelCase on the wire, snake_case in Python**, via `alias_generator=to_camel` | A silently-dropped `displaySurface` was a real bug we shipped. Any new multi-word field needs an alias test |
| **No authentication** (A11) — but the **address is the access control** (A19) | Product brief: no accounts. What decides who gets in is `MIRROR_ALLOW_CIDRS` (`src/mirror/access.py`), enforced in the HTTP middleware *and* before the socket accepts. If you think it needs auth, that is a `PLAN.md` discussion first — and see `SECURITY.md` |
| **Trust `X-Forwarded-For` only from `MIRROR_TRUSTED_PROXIES`, left-most value only** | Otherwise a browser writes its own pass. The deployment's nginx must *overwrite* the header (`$remote_addr`, never `$proxy_add_x_forwarded_for`) — and the nginx `allow`/`deny` list and `MIRROR_ALLOW_CIDRS` change in the same commit |
| **`/healthz` stays exempt from the address gate** | The podman `HealthCmd` probes it from loopback, which the production list otherwise excludes — an exempt probe is why the container is not permanently unhealthy |
| **No STUN/TURN by default** | A LAN tool must not announce internal addresses to a third party |
| **Teardown is broadcast to every viewer**, not just subscribers | Tiles are drawn on `stream_added`; a non-subscribed viewer still has a stale tile to clear |
| **Keep both `<video>` elements `muted playsinline`** | Autoplay policy on iOS/Safari otherwise blocks the wall entirely |
## 4. Gates — run all four before calling anything done
```bash
uv run ruff check . && uv run ruff format --check .
uv run pyright # must be 0 errors
uv run pytest # unit + API + browser E2E (~95s)
MIRROR_REALDISPLAY=1 uv run pytest -m realdisplay # Linux-native X11 capture
```
Coverage is ~95%; the media path is covered by browser assertions, not by unit
tests pretending to be WebRTC.
## 5. Browser testing rules
Non-negotiable, all learned the hard way (full notes in `PLAN.md` §5):
* Launch with **`channel="chromium"`**. The headless shell has no media stack —
`navigator.mediaDevices` does not exist there.
* Serve pages over **`http://127.0.0.1:<port>`**. On `about:blank` or a plain
LAN IP, `mediaDevices` is undefined and the test proves nothing.
* Deterministic capture: `--use-fake-ui-for-media-stream
--use-fake-device-for-media-stream` → a real, *moving* monitor stream
(1280×720 by default; clamped to the capturing window when a size is
requested).
* Real capture (the `realdisplay` suite): private **Xvfb**, headed Chromium,
`--auto-select-desktop-capture-source="Entire screen"`, `--ozone-platform=x11`,
and **never** `--use-fake-ui-for-media-stream` (it approves the request without
selecting a source and the capturer dies with `NotReadableError`).
* **Strip `WAYLAND_DISPLAY` and `DBUS_SESSION_BUS_ADDRESS`** from any headed
browser env (`tests/e2e/test_x11_capture.py::browser_env`). Otherwise the
portal captures the developer's actual desktop and pops a permission dialog on
their real screen.
* Assert media on the **viewer's** `<video>` — decoded size and *frames that
differ*. The sharer's preview proves nothing crossed the wire.
* Two browser **processes**, not two contexts, when a test means "two machines".
## 6. JavaScript rules
* Plain ES modules loaded with `<script type="module">`. No globals beyond
`window.__probe` in test scaffolding.
* Every element a script looks up (`$("#id")`) must exist in its page — enforced
by `test_every_element_the_script_reaches_for_exists`.
* Element ids must not collide **across** pages (one shared stylesheet):
`test_the_two_pages_share_no_element_ids_but_the_shared_chrome`. The only
allowed shared ids are `net`, `notice`, `toast`.
* WebRTC: the **sharer always offers, the viewer always answers**. Queue ICE
candidates until `remoteDescription` exists; serialise offers per peer to avoid
glare. Reuse `net.js` rather than duplicating socket logic.
* Never move a `<video>` element's `srcObject` to "switch views" — move the
element (that is how `/watch` staging works) so the peer connection survives.
## 7. Python rules
* `from __future__ import annotations`, full type hints, Google-style docstrings
on public functions.
* Starlette ≥1.10 raises **`WebSocketDisconnected`** (a `RuntimeError`) when the
app has already closed a socket, and `WebSocketDisconnect` when the peer does.
Catch both; read a socket you closed and you will crash the connection handler.
* Registry errors are `RegistryError(code, message, fatal)`; `fatal` means the
socket closes after the error frame is delivered. New error codes get a test.
* No bare `except:`; swallow only what you can name, and say why in a comment.
## 8. What to do when something behaves mysteriously
Reproduce at the lowest layer that can fail:
1. `curl -s localhost:8055/api/streams | python -m json.tool` — server truth.
2. `websocat ws://localhost:8055/ws` — speak the protocol by hand (see PLAN §3).
3. `uv run pytest tests/test_registry.py` — is the policy wrong, or the wiring?
4. Only then reach for a browser, and print `pageerror`/`console` from the first
line of the test.
## 9. Commits
* Conventional Commits (`feat:`, `fix:`, `test:`, `docs:`, `chore:`).
* Always `--no-gpg-sign`, always append the trailer `LLM-Generated: true`
(the `git-commit` skill does this).
* Never commit `.env`, keys, or `.agents/phase-sessions/`.
## 10. Quick reference
| I want to… | Do |
|---|---|
| Run it | `uv run mirror serve` → `:8055` |
| Share / watch | `/mirror` · `/watch` |
| Debug with an editor | `DEBUGPY=1 uv run mirror serve` (port 5678) |
| Server truth about mirrors | `GET /api/streams` |
| What the browser may know | `GET /api/config` |
| Everything fast, no browser | `uv run pytest -m "not e2e"` |
| Only the real-desktop test | `MIRROR_REALDISPLAY=1 uv run pytest -m realdisplay` |