Summary

Fixes three bugs in the context auto-compression system that collectively cause compression to never trigger for models with context_length at or near MINIMUM_CONTEXT_LENGTH (64000 tokens).

Bug 1: MINIMUM_CONTEXT_LENGTH floor makes threshold=100% when context_length==64000

Closes #14690

When context_length == MINIMUM_CONTEXT_LENGTH == 64000, the floor value in threshold_tokens calculation dominates:

# Before: max(44800, 64000) = 64000 = 100% of context → compression never triggers
self.threshold_tokens = max(
    int(self.context_length * threshold_percent),
    MINIMUM_CONTEXT_LENGTH,
)

Fix: Fall back to percentage-based value when floor >= context_length:

if self.threshold_tokens >= self.context_length:
    self.threshold_tokens = int(self.context_length * threshold_percent)

Applied in both __init__ and update_model.

Bug 2: Anti-thrashing protection permanently disables compression with no recovery

Closes #14694

After 2 consecutive ineffective compressions (<10% savings each), should_compress() returns False forever. No timeout, decay, or auto-recovery mechanism exists.

Fix: Add time-based auto-recovery (300 seconds). If enough time has passed since the last compression attempt, reset the counter:

if self._ineffective_compression_count >= 2:
    _elapsed = time.monotonic() - self._last_compression_time
    if _elapsed > self._ANTI_THRASH_RECOVERY_SECONDS:
        self._ineffective_compression_count = 0
    else:
        return False

Bug 3: Post-compression token estimate excludes tools schema

Closes #14695

After compression, last_prompt_tokens is set using estimate_messages_tokens_rough() which omits tools schema tokens (20-30K with 50+ tools). This causes the next compression cycle to trigger much later than the configured threshold.

Fix: Use estimate_request_tokens_rough() which includes tools schema, consistent with the preflight compression check pattern:

# Before:
_compressed_est = estimate_tokens_rough(new_system_prompt) + estimate_messages_tokens_rough(compressed)

# After:
_compressed_est = estimate_request_tokens_rough(
    compressed, system_prompt=new_system_prompt or "", tools=self.tools or None,
)

Testing

Verified with unit-level tests:

• Bug 1: context_length=64000, threshold=0.7 → threshold_tokens=44800 (70%), should_compress(44800)=True
• Bug 2: Anti-thrashing blocks within 300s window, auto-recovers after 300s elapsed
• Bug 3: estimate_request_tokens_rough includes tools schema in token count

Files Changed

• agent/context_compressor.py: Bug 1 fix (L320-321, L363-368) + Bug 2 fix (L299, L398-401, L418-436, L1283)
• run_agent.py: Bug 3 fix (L7596-7607)