黄云龙 e492bb1c68
fix(middleware): window LoopDetection tool-frequency counter so long runs don't false-trip (#4072)
* fix(loop-detection): decay per-tool frequency counter with a windowed deque

The Layer 2 per-tool-type frequency guard in _track_and_check used a
monotonic integer counter (freq[name] += 1) that never decayed or reset,
so a long-running thread could trip the frequency warn/hard-stop even when
calls were spread out over the whole run. Replace it with a deque of recent
tool names trimmed to window_size, matching the windowed hash layer, and
count occurrences within the window. Update _evict_if_needed and reset() to
manage the new _tool_name_history storage.

* address review: size Layer-2 freq window to the hard limit, not window_size

The windowed freq_count is bounded by the deque length; reusing Layer-1's
window_size (default 20) capped it below tool_freq_warn (30) / hard (50),
making the Layer-2 guard dead code under the shipped default config. Size
a dedicated _tool_freq_window = max(window_size, tool_freq_hard_limit,
override hard limits) so a tight burst reaches the limit while spread-out
calls still decay. Per @willem-bd review on #4072.

Adds default-config regression tests: freq window >= hard limit, override
coverage, and a tight-burst-with-distinct-args hard-stop under real defaults.

Co-Authored-By: Claude <noreply@anthropic.com>

* fix(#4072): docstrings describe windowed semantics; defaultdict+Counter for O(1)

Addresses willem-bds three inline nits:
1. Docstrings for tool_freq_warn/tool_freq_hard_limit now explain the
   sliding-window semantics and reference _tool_freq_window sizing.
2. Hot-path deque() allocation avoided: _tool_name_history uses
   defaultdict(deque) instead of dict.setdefault(thread_id, deque()).
3. O(window) sum() scan replaced with mirrored collections.Counter
   (incremented on append, decremented on popleft) for O(1) freq_count.

---------

Co-authored-by: Claude <noreply@anthropic.com>
2026-07-14 21:45:37 +08:00
..