# CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

## Project

cohere-transcribe — live speech-to-text using the Cohere ASR model (`CohereLabs/cohere-transcribe-03-2026`) via HuggingFace Transformers. Captures microphone audio, runs voice activity detection (VAD) to segment speech, transcribes each segment, and either prints text or injects it into the focused window via `wtype` (Wayland).

## Development Environment

Nix flake provides the dev shell (Python 3.14, portaudio, CUDA toolkit, wtype, uv). Direnv activates it automatically. Python deps managed by uv.

```bash
# Install/sync Python deps
uv sync

# Run the CLI (installed as entry point)
uv run cohere on          # start daemon (background, types into focused window)
uv run cohere off         # stop daemon
uv run cohere status
uv run cohere transcribe --stream   # live transcribe to terminal
uv run cohere transcribe --mic 5    # record 5s then transcribe
uv run cohere transcribe file.wav   # transcribe file

# Run mic tests
uv run python tests/test_mic.py
```

## Architecture

Two modes share the same model/VAD pipeline but differ in output:

- **Daemon mode** (`cohere on`): runs as a background process, transcribes speech segments and injects text into the focused window via `wtype`. State tracked in `~/.local/state/cohere/state.json`. The daemon is spawned by the CLI (`cli.py`) which launches `daemon_main.py` as a detached subprocess.
- **Stream/one-shot mode** (`cohere transcribe`): runs in foreground, prints transcriptions to stdout with timestamps.

### Key modules

- `model.py` — model loading (`load_model`) and transcription (`transcribe_audio`). Single source of truth for `MODEL_ID` and `SAMPLE_RATE` (16kHz).
- `vad.py` — RMS-based voice activity detection with `VADStateMachine`. Calibrates ambient noise threshold at startup. Configurable silence duration triggers segment boundaries.
- `stream.py` — streaming transcription loop: audio callback feeds VAD, completed segments go to a transcription worker thread via queue.
- `daemon.py` — same streaming pattern as `stream.py` but outputs via `wtype` instead of print. Also contains daemon lifecycle management (state file, PID tracking, start/stop).
- `cli/cli.py` — Typer CLI with `on`/`off`/`status`/`transcribe` commands.
- `transcribe.py` — original standalone script (not part of the package).

### Data flow

```
Microphone → sounddevice.InputStream (50ms frames)
  → VADStateMachine.process_frame()
  → speech segment detected → Queue
  → transcription_worker thread → transcribe_audio()
  → output (wtype or print)
```

## Conventions

- Package uses src layout (`src/cohere_transcribe/`), built with hatchling.
- Entry points: `cohere` and `cohere-transcribe` both map to `cohere_transcribe.cli:main`.
- VAD constants are in `vad.py` (frame size, pre-roll, silence limits, max segment length).
- Daemon state lives at `~/.local/state/cohere/` (state.json, daemon.log).
