* perf(summarization): skip the summarizer LLM call for an input already proven no-op
When the exact rendered summarizer prompt (plus candidate models) previously
produced output byte-identical to the current summary_text, reuse that summary
instead of calling the LLM. Compaction proceeds through the normal path, so
messages, hooks and state transitions are unchanged.
- Only proven no-op inputs are cached (bounded LRU, thread-safe); failed
attempts are never cached and any cache error falls back to the LLM call.
- The middleware:summarize event gains changes.llm_call_skipped.
- Applies to both compact_state and acompact_state.
Builds on the per-call telemetry in the P0 branch.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
* fix(summarization): keep fallback no-ops retryable
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Co-authored-by: Claude Sonnet 5.5 <noreply@anthropic.com>
Co-authored-by: Willem Jiang <willem.jiang@gmail.com>
