# Screens Agent Streamer — Hand-off

**Branch:** `screens-connection` in `ria-toolkit-oss`
**Status:** Part A complete (tests passing, 25/25). Part B is pending in the `ria-hub` repo.
**Related docs:** [screens_agent_streamer_plan.md](./screens_agent_streamer_plan.md), [../screens_connection_updates.md](../screens_connection_updates.md)

---

## What's done (Part A — this repo)

### Phase 1 — SDR foundation

- Added `ria_toolkit_oss.sdr.detect_available() -> dict[str, type]` that probes
  every driver module and returns the map of importable driver classes.
  Importability is used as a proxy for "user has installed this driver's
  optional dep"; it does **not** probe for physical hardware.
- Added `SdrDisconnectedError` (subclass of `SDRError`) plus a
  `translate_disconnect(exc)` helper in [sdr/sdr.py](../src/ria_toolkit_oss/sdr/sdr.py).
  Pattern-matches USB/device-drop exceptions (`ENODEV`/`EIO`, "no such device",
  "broken pipe", etc.) and converts them so the streamer can distinguish a
  real hardware failure from a transient error.
- Audited every driver under `sdr/` for GUI imports — none found. All drivers
  are headless-clean at import time.
- `Pluto.rx(num_samples)` now wraps `self.radio.rx()` with
  `translate_disconnect`. The same one-liner pattern can be applied to other
  drivers (hackrf/rtlsdr/usrp/blade/thinkrf) when they get wired to the
  streamer — deferred until each is needed.

**Not done (Phase 1 Task 4):** SigMF recording validation across radio types —
needs real captures from each device, out of scope without hardware.

### Phase 2 — Agent package restructure

Moved the former `src/ria_toolkit_oss/agent.py` into a package:

```
src/ria_toolkit_oss/agent/
├── __init__.py          # re-exports NodeAgent + main for back-compat
├── legacy_executor.py   # former agent.py, unchanged behavior
├── streamer.py          # new WebSocket IQ streamer
├── ws_client.py         # persistent WS client + heartbeat + reconnect
├── hardware.py          # wraps sdr.detect_available() for heartbeat payloads
├── config.py            # ~/.ria/agent.json load/save (0600 perms)
└── cli.py               # unified CLI (run / stream / detect / register)
```

Back-compat preserved: `from ria_toolkit_oss.agent import NodeAgent` still
works, and bare `ria-agent ...` with no subcommand (or with legacy flags
like `--hub`) falls through to the original long-poll executor.

### Phase 3 — Streamer implementation

- `ws_client.WsClient` — `async run()` loop, JSON heartbeats on a timer,
  auto-reconnect on drop, bearer-token auth header on connect.
- `streamer.Streamer` — handles `start` / `stop` / `configure` messages,
  opens the SDR via an injectable `sdr_factory`, runs capture in an executor
  thread, and ships raw interleaved float32 IQ bytes per `rx()` call.
- `hardware.heartbeat_payload(status, app_id)` — `{type, hardware[], status}`.
- `config.AgentConfig` — dataclass round-tripped through JSON, unknown keys
  preserved in an `extra` dict.
- CLI subcommands: `run` (legacy), `stream`, `detect`, `register`.

### Phase 4 — Protocol

Matches `screens_connection_updates.md` §"WebSocket Protocol" exactly:

| Direction | Message |
|-----------|---------|
| A → S (JSON) | `{type: heartbeat, hardware[], status}` |
| A → S (JSON) | `{type: status, status, app_id}` |
| A → S (JSON) | `{type: error, app_id, message}` |
| A → S (binary) | raw interleaved float32 IQ, one frame per `rx()` |
| S → A (JSON) | `{type: start, app_id, radio_config}` |
| S → A (JSON) | `{type: stop, app_id}` |
| S → A (JSON) | `{type: configure, app_id, radio_config}` — applied at next boundary |

**Auth decision:** bearer token in `Authorization` header on the initial
handshake. (Open questions in the plan around first-frame auth / mid-buffer
`configure` / backpressure remain open.)

### Phase 5 — Tests

25 tests, all green under `poetry run pytest tests/agent/`:

- `test_hardware.py` — `detect_available`, heartbeat payload shape
- `test_config.py` — round-trip, missing-file fallback, extra-key preservation
- `test_streamer.py` — start/stream/stop against `MockSDR` + fake WS, error
  frames, configure queueing
- `test_disconnect.py` — `translate_disconnect` patterns + streamer reports
  `SDR disconnected:` and closes the SDR
- `test_ws_client.py` — real local `websockets` server: heartbeat on connect,
  auto-reconnect after server drop, malformed-frame resilience
- `test_integration.py` — end-to-end heartbeat → start → 3 binary IQ frames → stop
- `test_legacy.py` — regression: `NodeAgent` still importable

### Dependency / build changes

- Added `websockets (>=12.0,<14.0)` to `[tool.poetry.group.agent.dependencies]`.
- Repointed the `ria-agent` console script from `ria_toolkit_oss.agent:main`
  to `ria_toolkit_oss.agent.cli:main` (the unified CLI, which still calls
  through to the legacy `main` for back-compat).

### Files changed

```
M  pyproject.toml
M  poetry.lock
M  src/ria_toolkit_oss/sdr/__init__.py
M  src/ria_toolkit_oss/sdr/sdr.py
M  src/ria_toolkit_oss/sdr/pluto.py
R  src/ria_toolkit_oss/agent.py -> src/ria_toolkit_oss/agent/legacy_executor.py
A  src/ria_toolkit_oss/agent/{__init__,cli,config,hardware,streamer,ws_client}.py
A  tests/agent/{__init__,test_config,test_disconnect,test_hardware,
               test_integration,test_legacy,test_streamer,test_ws_client}.py
A  docs/screens_agent_streamer_plan.md
A  docs/screens_agent_handoff.md  (this file)
```

---

## What's left (Part B — `ria-hub` repo)

In priority order. B1 + B2 + B3 + B6 are the MVP; everything else hardens.

### Server-side (MVP)

| # | Task | File / area |
|---|------|-------------|
| B1 | Implement `AgentDataSource` (DataSource ABC, reads IQ from WS connection) and register in `build_data_source()` | `controller/app/modules/screens/data_sources.py` |
| B2 | Add `"agent"` to `dataSource.type` enum in manifest schema; update Pydantic / JSON schema validators | `controller/app/modules/screens/graph_derivation.py` + schema files |
| B3 | Agent WebSocket endpoint `POST /api/agent/ws` (or `GET` with Upgrade) — accepts agent connections, auths on bearer token, bridges the connection to the Celery task's `AgentDataSource` | new `controller/app/modules/agent/routes.py` |
| B6 | Celery wiring: when `dataSource.type == "agent"`, look up the connected agent by `agent_id`, forward `radio_config` as a `start` message, and feed received IQ bytes into the inference loop via `AgentDataSource.next_chunk()` | `controller/app/modules/screens/tasks.py` |

### Server-side (hardening)

| # | Task |
|---|------|
| B4 | Agent registry — MongoDB collection: `agent_id`, `hardware[]`, `last_heartbeat`, `online`, registration tokens |
| B5 | `POST /api/agent/register` returning `{agent_id, token}` for `~/.ria/agent.json` |

### Frontend

| # | Task |
|---|------|
| B7 | Device / agent picker in the Screens app config (Vue 3) |
| B8 | Agents list / status admin view |

### Protocol contract (keep in lockstep with Part A)

- Binary frames are interleaved float32 IQ, one frame per `radio.rx()` call.
- `radio_config` is forwarded verbatim from manifest `dataSource.params`.
  Minimum keys the agent handles: `device`, `identifier`, `sample_rate`,
  `center_frequency`, `gain`, `buffer_size`.
- `configure` messages from the server apply at the next capture boundary
  (current agent implementation).
- Agent authenticates with bearer token in `Authorization` header on the
  handshake.

### Still-open protocol questions (pin down before B3 lands)

- Auth frame as fallback when proxies strip `Authorization`?
- Mid-buffer `configure` application for tighter retune latency?
- Backpressure policy when the server's inference loop is slower than the
  agent's `rx()` cadence — drop, queue, or pause the agent via a `pause`
  control frame?

### Manifest example (new `agent` mode)

```json
{
  "dataSource": {
    "type": "agent",
    "device": "pluto",
    "agent_id": "agent-abc123",
    "params": {
      "identifier": "ip:192.168.3.1",
      "sample_rate": 1000000,
      "center_frequency": 2450000000,
      "gain": 40,
      "buffer_size": 1024
    }
  },
  "preprocess": "magnitude_phase_window_stats",
  "config": {"inference": {"knownDevices": [], "interval": 1}}
}
```

### Pipeline invariant

**No changes to `inference_core.py`, `preprocessors.py`, or
`run_onnx_chain_loop()`.** `AgentDataSource` is a drop-in replacement for
`SdrDataSource`; everything downstream is unchanged.

---

## Local test setup

### 1. Branch layout

- `ria-toolkit-oss` — branch **`screens-connection`** (this work).
- `ria-hub` — whatever branch you'll be doing Part B on (create a matching
  `screens-connection` branch there to keep the hand-off clean).

### 2. Install the toolkit branch into your local RIA Hub

The hub declares `ria-toolkit-oss` as a git dep in its `pyproject.toml`.
Point it at this branch:

```toml
# ria-hub/pyproject.toml
ria-toolkit-oss = { git = "https://riahub.ai/qoherent/ria-toolkit-oss.git", branch = "screens-connection" }
```

Or for a fully local dev loop (edits visible without reinstall):

```bash
# from ria-hub repo
poetry run pip install -e /home/qrf/ria-toolkit-oss
# plus the agent extra so websockets is available server-side too
poetry run pip install websockets
```

### 3. Commit this branch and push (optional, for CI / shared dev)

```bash
cd /home/qrf/ria-toolkit-oss
git add -A
git commit -m "Add WebSocket IQ streamer agent (Part A)"
git push -u origin screens-connection
```

### 4. Try the agent locally against a mock server

You can exercise the whole Part A stack without RIA Hub by running the
integration test:

```bash
cd /home/qrf/ria-toolkit-oss
poetry run pytest tests/agent/test_integration.py -v
```

Or manually, once Part B lands:

```bash
# on the user machine (mock hardware is fine)
ria-agent register --url https://localhost:8000 --token <tok>
ria-agent detect          # lists: mock, pluto, ... whatever's importable
ria-agent stream --url ws://localhost:8000/api/agent/ws
```

### 5. End-to-end integration test (after Part B MVP)

1. Start RIA Hub (FastAPI + Celery + Mongo + Redis) with the Part B branch.
2. Run `ria-agent stream` on your laptop.
3. Create a Screens app with `dataSource.type: "agent"` and `device: "mock"`.
4. Start the app; confirm the agent logs "streaming" and the SSE stream
   shows inference metrics flowing.