The traffic learner was emitting one-shot error_recovery patterns that
contradicted each other and bloated MEMORY.md with low-signal noise. Two
issues drove this:
1. The shutdown flush bypassed the evidence gate: the in-memory
_min_evidence was set to 2, but on stop() the gate dropped to 1, so
every singleton pattern got persisted at session end. This is the
opposite of how evidence thresholding should work — singletons are
the least trustworthy patterns, not the most.
2. The default min_evidence of 2 is too low to filter noise from the
matchers, which pair up failed/successful tool calls within a small
sliding window without a strong semantic check that the calls are
actually related.
Changes:
- Raise default min_evidence from 2 to 5 in TrafficLearner.
- Remove the shutdown-relaxation in flush_to_files; require
self._min_evidence at all times, including on stop().
- Add traffic_learning_min_evidence to ProxyConfig (default 5).
- Add --min-evidence CLI flag with HEADROOM_MIN_EVIDENCE envvar so
users and embedded clients (desktop apps, plugins) can tune the
threshold without source changes.
- Thread the config value through HeadroomProxy into TrafficLearner.
- Tests: cover default propagation and custom value flow.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
