Replace the LLM-per-request flow in /pm with a stateful Python backend
(OpenSquawk-LiveATC-api). The backend owns session state, does regex-first
routing with readback evaluation, and returns the next state + ATC speech.
The frontend keeps its local cursor (communicationsEngine) for TTS and
monitoring UI, but no longer calls /api/llm/decide.
Changes:
app/composables/useRadioBackend.ts (new)
Typed Nuxt composable wrapping the Python REST API:
createSession, transmit, deleteSession, fetchFlows.
Base URL read from NUXT_PUBLIC_RADIO_BACKEND_URL (default 127.0.0.1:8000).
nuxt.config.ts
Expose radioBackendUrl as a public runtime config key so the composable
and communicationsEngine can both reach the Python backend.
shared/utils/communicationsEngine.ts
- fetchRuntimeTree now accepts an optional baseUrl so it fetches from the
Python backend instead of the Nuxt server when a URL is provided.
- renderTpl handles both {var} (old MongoDB schema) and {{var}} (new YAML
schema) — double-brace matched first to avoid partial matches.
- stateSayTpl / stateUtteranceTpl helpers unify say_tpl|say_template and
utterance_tpl|expected_pilot_template across both schema versions.
- auto_transitions from the new YAML schema are included when collecting
eligible transitions in collectAtcStatesUntilPilotTurn.
shared/types/decision.ts
RuntimeDecisionState extended with say_template and expected_pilot_template
fields (new YAML schema field names alongside the existing legacy names).
app/pages/pm.vue
- startMonitoring: loads tree from Python backend, then creates a backend
session (backendSessionId). Cursor synced to session.current_state.
- handlePilotTransmission: calls radioBackend.transmit instead of
/api/llm/decide. Applies auto_advanced_states via moveToSilent, then
the final state. Speaks controller_say_template via TTS.
- Both fetchRuntimeTree calls now pass radioBackendUrl so they hit the
Python backend, not the Nuxt flow-from-MongoDB path.
AGENTS.md (new)
Project guide updated to document the new two-backend architecture,
the Python backend session lifecycle, and the dual template schema.
docs/plans/2026-05-06-pm-python-runtime-contract.md (new)
Implementation plan and API contract written before the work started.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
- Fix client: playbackRate was set to 1 for non-native-speed providers (Speaches/Piper),
making the speed slider ineffective in the main Pizzicato audio path
- Fix server: pass speed parameter to Speaches TTS API
- Add pitch-preserving playback via MediaElementSourceNode when rate != 1,
routing through the same Web Audio effects chain (radio filters, distortion, etc.)
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
