# 03 — Gateway Plugin (Python)

The plugin is a **community-style hermes platform plugin** named `iris`.
It follows the "Plugin Path" in `hermes-agent/gateway/platforms/ADDING_A_PLATFORM.md`
and the canonical example `hermes-agent/plugins/platforms/irc/adapter.py`.
**Zero hermes-core changes. Zero new Python dependencies** (`websockets` and
`httpx` are already core deps).

> Source map for every hermes integration point: see `15-hermes-reference.md`.

## 3.1 `plugin.yaml` (manifest)

```yaml
name: iris-platform
label: Android
kind: platform
version: 0.1.0
description: >
  Native Android / Desktop client gateway adapter for Hermes Agent.
  Runs a WebSocket server inside the gateway; the app connects with a
  pairing token. Supports streaming, reasoning, structured tool events,
  channels/threads, media, FTS5 search, and FCM/ntfy push.
author: <you>
requires_env:
  - name: IRIS_TOKEN
    description: "Shared pairing token the app presents on connect"
    prompt: "Android pairing token"
    password: true
optional_env:
  - name: IRIS_WS_HOST
    description: "WS bind host (default 127.0.0.1; use 0.0.0.0 for LAN)"
    prompt: "WS host"
    password: false
  - name: IRIS_WS_PORT
    description: "WS port (default 8790)"
    prompt: "WS port"
    password: false
  - name: ANDROID_HOME_CHANNEL
    description: "Default chat id for cron/notification delivery (default default)"
    prompt: "Home channel"
    password: false
  - name: IRIS_ALLOWED_USERS
    description: "Comma-separated allowed device_ids (empty = token-only auth)"
    prompt: "Allowed device ids"
    password: false
  - name: IRIS_ALLOW_ALL_USERS
    description: "Allow any paired device (dev only)"
    prompt: "Allow all devices? (true/false)"
    password: false
  - name: IRIS_PUSH_BACKEND
    description: "Push backend: fcm (default) or ntfy"
    prompt: "Push backend"
    password: false
  - name: IRIS_FCM_SERVICE_ACCOUNT
    description: "Path to Firebase service-account JSON (FCM HTTP v1)"
    prompt: "FCM service account path"
    password: true
  - name: IRIS_FCM_SERVER_KEY
    description: "Legacy FCM server key (fallback if no service account)"
    prompt: "FCM server key"
    password: true
  - name: NTFY_TOPIC
    description: "ntfy topic for push (when IRIS_PUSH_BACKEND=ntfy)"
    prompt: "ntfy topic"
    password: false
  - name: NTFY_SERVER_URL
    description: "ntfy server URL (default https://ntfy.sh)"
    prompt: "ntfy server URL"
    password: false
  - name: IRIS_WS_CERT
    description: "TLS cert path for WSS (optional)"
    prompt: "WSS cert"
    password: false
  - name: IRIS_WS_KEY
    description: "TLS key path for WSS (optional)"
    prompt: "WSS key"
    password: false
```

Behavioral (non-secret) settings live in `config.yaml` under
`gateway.platforms.iris.extra` (host, port, home_channel, outbox retention,
max upload bytes, tls). Secrets live in `.env`. (hermes policy: `.env` = secrets
only.)

## 3.2 `register(ctx)` entry point

```python
def register(ctx):
    ctx.register_platform(
        name="iris",
        label="Iris",
        adapter_factory=lambda cfg: IrisAdapter(cfg),
        check_fn=check_requirements,          # passive: websockets importable + token set
        validate_config=validate_config,      # host/port/token present
        is_connected=is_connected,
        required_env=["IRIS_TOKEN"],
        install_hint="No extra packages needed (websockets + httpx are core deps)",
        setup_fn=interactive_setup,           # hermes gateway setup flow
        env_enablement_fn=_env_enablement,    # seed extra + home_channel from env
        cron_deliver_env_var="ANDROID_HOME_CHANNEL",
        standalone_sender_fn=_standalone_send,  # best-effort out-of-proc cron (stretch)
        parse_target_ref_fn=_parse_target_ref,  # "iris:<chat>[:<thread>]"
        allowed_users_env="IRIS_ALLOWED_USERS",
        allow_all_env="IRIS_ALLOW_ALL_USERS",
        max_message_length=0,                 # 0 = no limit (WS has none)
        emoji="📱",
        pii_safe=False,
        platform_hint=(
            "You are chatting with the user through their native Iris app "
            "(Android/Desktop). It renders Markdown, inline code, images, "
            "audio and video, and shows your reasoning and tool activity. "
            "Conversations are organized into channels and optional threads. "
            "Keep formatting rich but readable."
        ),
    )
```

Field reference (all from `PlatformEntry`, `gateway/platform_registry.py:63`):
`adapter_factory`, `check_fn`, `validate_config`, `is_connected`, `required_env`,
`install_hint`, `setup_fn`, `env_enablement_fn`, `apply_yaml_config_fn`,
`cron_deliver_env_var`, `parse_target_ref_fn`, `allowed_users_env`,
`allow_all_env`, `max_message_length`, `pii_safe`, `platform_hint`, `emoji`,
`ensure_deps_fn`.

- **`check_requirements()`** — passive probe: `import websockets` succeeds and
  `IRIS_TOKEN` is set. Never installs.
- **`_env_enablement()`** — returns a dict seeding `PlatformConfig.extra`
  (host/port/home_channel/push_backend) + a `home_channel` key
  `{"chat_id": "default", "name": "Default"}` so `hermes gateway status`
  and cron home-channel resolution work without instantiating the adapter.
- **`_parse_target_ref(ref)`** — the core strips the platform prefix first, so
  `ref` is the direct chat id (e.g. `chan_7`, `default`) with an optional
  `:t_<n>` thread suffix; friendly names resolve via the channel directory.
  Returns `(chat_id, thread_id)` or `None`.
- **`interactive_setup()`** — prompts for token (or generates one), host/port,
  push backend + credentials, prints a QR code (pairing) and the app URL.

## 3.3 `IrisAdapter(BasePlatformAdapter)`

Constructor: `super().__init__(config=config, platform=Platform("iris"))`.
Reads `config.extra` (env overrides win). Initializes: WS server (not started
until `connect()`), connection registry, outbox (SQLite under
`get_hermes_home()/"iris"`), push backend, pairing store, channel directory.

### Lifecycle

- **`connect(*, is_reconnect=False) -> bool`**
  - Acquire scoped lock (`gateway.status.acquire_scoped_lock("iris", key)`)
    so two profiles can't bind the same port/identity.
  - Start the `websockets` server on `host:port` (TLS if cert/key set).
  - `_mark_connected()`; return True.
- **`disconnect()`**
  - Stop server, close all device sockets, release lock, `_mark_disconnected()`.

### Inbound (app → agent)

- WS `message.send {text, reply_to?, media_refs?}` → build `SessionSource` via
  `self.build_source(chat_id, chat_name, chat_type, user_id, user_name,
  thread_id)` → build `MessageEvent(text=…, message_type=TEXT, source=…,
  media_urls=[cached paths], media_types=[…], reply_to_message_id=…)` →
  `await self.handle_message(event)`.
- Slash commands arrive as plain text starting with `/`; the gateway's command
  pipeline resolves + dispatches them (no special handling needed).
- `picker.select {picker_id, value}` → route to the gateway-side resolvers
  (model picker / choice picker / clarify / approval / slash-confirm) using the
  shared callback-id conventions (`cl:<id>:<idx>`, `appr:<id>:<choice>`,
  `sc:<choice>:<id>`).
- `channel.create` / `channel.rename` / `channel.set_default` → mutate the
  channel directory (SQLite) + emit `channel.*` frames to all devices.
- `search {query, scope, chat_id?, thread_id?}` → `search.py` → `search.results`.
- `media.upload` (chunked) → `media.py` → `cache_*_from_bytes` → `media_ref`.
- `media.pull {media_id}` → stream cached bytes as binary frames.
- `fcm.register {token}` / `hello` → update device registry.
- `read.receipt {message_id}` → mark delivered/read (drives ✓✓), ack.
- `sync {cursor}` → `outbox.py` → replay frames since cursor.

### Outbound (agent → app)

- **`send(chat_id, content, reply_to=None, metadata=None) -> SendResult`**
  - Split reasoning prefix (see `05-streaming.md`) → `reasoning` field.
  - If **any** device is connected: broadcast `message` frame to all.
  - Else (no live devices): append to **outbox** + fire **push** (FCM/ntfy).
  - Return `SendResult(success=True, message_id=<id>)`.
- **`edit_message(chat_id, message_id, content)`** → `message.update` frame
  (drives streaming). If no device, no-op (outbox holds the final `send`).
- **`send_typing(chat_id, metadata=None)`** → `typing` frame.
- **`get_chat_info(chat_id) -> dict`** → `{"name": <channel name>, "type": "dm"|"channel"}`
  from the channel directory.
- **Media send** — `send_image / send_video / send_document / send_voice /
  send_image_file / send_multiple_images`: stage the file in the media cache,
  mint a `media_id`, emit `media.offer {media_id, mime, size, filename, kind}`,
  serve bytes on `media.pull`. (Base-class `extract_media`/`extract_images`
  already pull `MEDIA:`/image tags out of agent text and call these.)
- **Interactive pickers** — `send_model_picker(...)`, `send_choice_picker(...)`,
  `send_clarify(...)`, `send_exec_approval(...)`, `send_slash_confirm(...)`:
  emit `picker.model` / `picker.choice` / `picker.clarify` / `picker.approval` /
  `picker.confirm` frames with options; store pending state keyed by
  `picker_id`; resolve on `picker.select`.
- **`create_handoff_thread(chat_id, name)`** → create a thread id, register in
  channel directory, return it (used by cron "continuable" threads).

### Streaming hooks

The main gateway drives delivery through the **legacy callback path**:

- `stream_delta_callback` → `GatewayStreamConsumer` → `send()` (first) +
  `edit_message()` (updates) → `message.start` / `message.update`.
- `tool_progress_callback` → progress queue → `send_progress_messages` →
  `send()` → `tool.*` frames (structured; classified in the adapter).
- `interim_assistant_callback` → consumer `on_commentary` → `send()` →
  `commentary` frames.

The adapter tracks per-chat **turn state** (in-turn, current streaming
`message_id`, last tool index) to classify outbound `send()` calls into
`message` vs `tool.*` vs `commentary`. The exact classification markers are
verified empirically in M2 (see `13-testing.md`).

## 3.4 WebSocket server (`ws_server.py`)

- Library: **`websockets`** (core dep, v15). `websockets.serve(handler, host,
  port, ssl=ctx)`.
- **Handler** per connection:
  1. Await first frame; must be `hello {token, device_id, device_name, caps,
     fcm_token?}`. Verify token (constant-time) + allowlist. On failure: send
     `error {code:"auth"}` and close.
  2. On success: register in connection registry
     (`device_id → {ws, caps, fcm_token}`), send
     `hello.ack {server_caps, sync_cursor, channels[]}`.
  3. Loop: decode frames, dispatch to adapter inbound handlers.
  4. On close: deregister; if no devices remain, ensure pending outbox
     frames have push fired.
- **Routing:** `emit(chat_id, frame)` → broadcast to **all** connected
  devices (no per-chat subscribe; single-user model). Global frames
  (`channel.*`, `status`) also broadcast to all.
- **Heartbeat:** WS ping/pong + app-level `ping`/`pong`; dead peers reaped.
- **Backpressure:** per-connection send queue with a bounded buffer; drop
  `message.update` (coalesce to latest) under pressure, never drop
  `message`/`tool.end`/`notification`.

## 3.5 State & storage (all under `get_hermes_home()/"iris"`)

> Use `get_hermes_home()` from `hermes_constants` for **all** paths (profile-safe).
> Never hardcode `~/.hermes`.

- `devices.db` — device registry (device_id, name, caps, fcm_token, ntfy_topic,
  last_seen, created).
- `channels.db` — channel directory (chat_id, name, kind: default|channel|thread,
  parent_chat_id, created, is_default).
- `outbox.db` — undelivered frames per chat_id + monotonic cursor.
- `media/` — inbound + outbound media cache (reuse hermes `cache_*_from_bytes`
  dirs where possible).

## 3.6 Config resolution

- **Secrets (`.env`):** `IRIS_TOKEN`, `IRIS_FCM_SERVICE_ACCOUNT`,
  `IRIS_FCM_SERVER_KEY`, `IRIS_WS_CERT/KEY`, `NTFY_TOPIC` (if secret).
- **Behavioral (`config.yaml` → `gateway.platforms.iris.extra`):** `host`,
  `port`, `home_channel`, `allowed_users`, `push_backend`, `outbox_retention_hours`,
  `max_upload_bytes`, `tls`.
- Env vars override `config.yaml` (hermes convention). Read secrets with the
  scope-aware `_get_scoped_secret` pattern (see `plugins/platforms/irc/adapter.py:42`)
  so multiplexed profiles don't leak each other's tokens.

## 3.7 Failure & lifecycle safety

- WS server bind failure → `_set_fatal_error("bind_failed", …, retryable=True)`.
- All outbound sends are best-effort; a dead socket latches and the frame falls
  to the outbox.
- `disconnect()` cancels the server task and closes sockets cleanly.
- Token/PII redaction in all logs (hermes PII policy).