feat(planner-agent): add llm_router.py with local-first fallback chain
services/planner-agent/src/llm_router.py:
- LLMRouter: async routing via litellm; chain = Qwen/Ollama → haiku → sonnet
- Timeouts: 8s local, 30s cloud; asyncio.wait_for belt-and-suspenders
- Rejection triggers: timeout, API error, refusal patterns, JSON schema fail
- JSON fence extraction: recovers valid JSON from blocks
- ModelMetrics: per-model success/fallback/error counters + success_rate()
- Redis publish to 'llm_router_metrics' after every call (failure-safe)
- redis_url=None disables Redis (useful in tests / edge nodes)
- context= param adds caller label to all log lines for tracing
services/planner-agent/tests/test_llm_router.py:
- 34 tests, 0 network calls (litellm + Redis fully mocked)
- Covers: primary success, JSON error fallback, refusal fallback,
timeout fallback, API exception fallback, all-fail RuntimeError,
schema validation, fence extraction, metrics recording, Redis publish,
Redis failure isolation
services/planner-agent/requirements.txt:
- litellm>=1.40.0, redis>=5.0.0, jsonschema>=4.21.0
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Oskar Kapala
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