fix: tool_output_limits re-reads config file on every tool call

[amathxbt]

Bug

tools/tool_output_limits.py calls _load_config() on every invocation of get_output_limit(). _load_config opens and parses the YAML config file from disk each time.

Impact

In workloads that invoke many tool calls per second (e.g. batch file editing, large agentic loops), this creates continuous disk I/O and YAML parsing overhead. On network-mounted or slow storage the latency compounds.

Fix

Cache the parsed config in a module-level dict with a TTL (default 60 s). Adds _reset_config_cache() for tests and hot-reload.

[amathxbt]

Reproduction (profiling)

import time
from tools.tool_output_limits import get_output_limit

N = 1000
start = time.perf_counter()
for _ in range(N):
    get_output_limit('read_file')
elapsed = time.perf_counter() - start
print(f'{N} calls: {elapsed:.3f}s')
# Typically 0.5–2 s depending on disk speed — every call opens + parses YAML

Root cause: _load_config() has no cache — it opens the YAML file on every call.

Fix: Module-level dict cache with 60-second TTL. In a 100-tool-call workload (typical agentic loop) this reduces config I/O from 100 file reads to 1–2.

[teknium1]

This has already landed on current main via the perf-fix salvage batch. This is an automated hermes-sweeper review.

Evidence:

• tools/tool_output_limits.py:43 defines the module-level _cached_limits cache, and tools/tool_output_limits.py:70 returns the cached value before reloading config.
• tools/tool_output_limits.py:92 includes _reset_tool_output_limits_cache() for tests / reload paths.
• tests/tools/test_tool_output_limits.py:25 resets the cache around tests so patched config values do not leak across cases.
• Commit 91a98d15190181814b68792a0431ae8bc034e462 is fix: tool_output_limits re-reads config on every call (no caching) and is contained in v2026.6.5.
• Merged PR perf: batch salvage of 5 verified micro-fixes (cache leaks, per-call waste, blocking sleep, O(n²) drain) #35758 explicitly lists fix: tool_output_limits re-reads config file on every tool call #22155 as included in its batch salvage.