# Observability severity patch

- Central `severity_policy.py` classifies explicit MCP failures, guardrail blocks, judge rejections, RAG failures and memory/cache errors.
- `Telemetry.event()` accepts `level` and `status_message` and preserves WARNING/ERROR events as individual observations in compact mode.
- `Telemetry.span()` handle supports `set_status(level, message)`; failed MCP results mark their span ERROR without raising exceptions.
- Long-term-memory read/write failures emit telemetry while preserving existing fallback behavior.
- Guardrail blocked and negative judge evaluation emit WARNING when these helper methods are invoked.
- Normal cache misses and empty RAG results are not automatically failures.

## Scope / limitations
- Existing call sites must invoke `GuardrailTelemetry.blocked` for guardrail blocking events; this patch does not rewrite every pipeline call site.
- Redis cache currently has no injected Telemetry instance, so its existing logger errors are not yet Langfuse observations. A separate dependency-injection change is required to cover that path safely.
- RAG database connection errors that are caught by external KBDB integrations without emitting a telemetry event cannot be classified automatically.
- No live Langfuse ingestion test was possible in this environment. Verify both compact and verbose modes against your server.

## Validation
`PYTHONPATH=libs/agent_framework/src python -m pytest -q tests/test_observability_severity_policy.py`