U1: Add estimate_text_tokens() module-level function with CJK 1:1 / ASCII
4:1 heuristic. Update estimate_tokens(), _summarize() pre-truncation, and
react.py _should_compress() fallback to use it. Fixes 4x token
underestimation for Chinese/Japanese/Korean conversations.
U3: Rewrite compress() from recursive _compression_depth to linear flow
(summarize -> aggressive -> truncate). Add _log_compression() structured
logging with tokens_before/after/ratio/strategy. Remove _compression_depth
parameter from compress() and _compress_aggressive().
Per plan: docs/plans/2026-07-02-003-feat-context-compressor-cjk-prefix-enhancement-plan.md
U3: ContextCompressor now accepts model_context_limit, headroom_threshold,
and min_tokens. should_compress() triggers when token ratio exceeds 0.8 of
model limit OR exceeds min_tokens (8000 fallback). ReActEngine._should_compress
delegates to compressor when available, checks is_available() first.
Tests: 6 scenarios (headroom trigger, min_tokens guard, small model,
unavailable compressor, delegation, fallback) — all pass.
Add runtime-checkable CompressionStrategy Protocol with compress(),
compress_tool_result(), and is_available() methods. Add compress_tool_result
and is_available to existing ContextCompressor. Add create_compressor()
factory function with headroom/summary provider routing and ImportError
fallback.
chiguyong
Fischer