# Rutster Echo Brain (Python reference)

The canonical foreign-language brain for slice-2. Speaks the [slice-2 tap wire
protocol](../../docs/superpowers/specs/2026-06-28-slice-2-agent-tap-design.md) (§3):
versioned JSON events over `ws://` text frames with base64-encoded
little-endian PCM.

## Why a Python brain?

The architecture (ARCHITECTURE.md §"Agent tap") names "a Python script" as the
canonical brain persona. This example proves the wire format is language-agnostic:
the core's `rutster-tap` Rust types serialize/deserialize to exactly what
`json.loads` + `websockets` produces. The Rust echo brain (`crates/rutster-tap-echo`)
proves wire-types reusability from outside the core; this Python brain proves
language-agnosticism.

## Run

```bash
pip install -r examples/echo_brain/requirements.txt
python examples/echo_brain/echo_brain.py
# [echo_brain] listening on ws://127.0.0.1:8081/echo
```

Then in another terminal:

```bash
cargo run  # the core dials out to ws://127.0.0.1:8081/echo by default
```

## Not in CI

This script is **not** run by CI. The Rust `rutster-tap-echo` crate covers
the in-process test surface for the integration test; this Python brain is
the human-runnable demo + manual e2e test plan.

## Protocol

See [the spec](../../docs/superpowers/specs/2026-06-28-slice-2-agent-tap-design.md)
§3 for the full wire protocol. Key behavior:

- On `hello`: ack with `hello` (echo the `session_id`).
- On `audio_in`: echo the same PCM back as `audio_out` (advisory — core
  disposes).
- On `bye` / `session_end`: close cleanly.
- Stateless across reconnects (spec §5.3) — every `hello` starts fresh.