Trace Viewer

The viewer (src/nooa/viewer/) is a single FastAPI app that is both the OTLP receiver agents send spans to and the web UI (React SPA) for browsing traces, LLM calls, and evaluation experiments. Traces persist in SQLite, so they survive restarts.

Start it

nooa start-dev                                  # http://localhost:5001
nooa start-dev --port 5002                      # custom port
nooa start-dev --db /path/to/other.db           # separate trace store
nooa start-dev --host 127.0.0.1                 # default host is 0.0.0.0

Stop with Ctrl-C. If deps are missing: uv sync --extra viewer. If the port is busy, the command reports the offending PID.

• Database resolution: --db > $NOOA_TRACE_DB > ~/.config/nooa/traces.db.
• Alternate entry point: python -m nooa.viewer (this path honors $NOOA_TRACE_VIEWER_PORT, default 5001; start-dev uses --port instead). DB default for the raw module is ./traces.db — prefer start-dev.

End-to-end workflow