`load_config()` is called from the agent loop's per-API-call hot path via
`get_provider_request_timeout()` and `get_provider_stale_timeout()` —
both invoked once per turn from `_resolved_api_call_timeout()` in
run_agent.py.
Profiling a synthetic 20-tool-call agent run revealed:
- 21 invocations of `load_config()` cumulating 56ms (~17% of agent loop)
- 34,398 deepcopy calls totaling 37ms (config defensive deepcopy + chain)
- 8,652 `_expand_env_vars` invocations (~412 per turn)
Microbench (cache-hit, real config.yaml present):
load_config() 265us/call (125us deepcopy + 140us infra)
load_config_readonly() 138us/call (~48% faster)
`load_config_readonly()` returns the cached dict directly without the
defensive deepcopy. Documented contract: caller must not mutate. Returns
plain dict (not MappingProxyType) so downstream `isinstance(x, dict)`
guards keep working — caught during initial implementation when
MappingProxyType broke get_provider_request_timeout's guard logic.
Wired into hermes_cli/timeouts.py (the two functions called per agent
turn). load_config() is unchanged for the 263 other call sites that
mutate the result before save_config(), are not in the hot path, or
where the safety guarantee matters more than the perf.
Profile A/B (cached config, 21-turn agent loop):
BEFORE AFTER delta
get_provider_request_timeout 55ms 16ms -71%
total function calls 399k 160k -60%
deepcopy calls (in hotspots) 34,398 ~0 ~elim
Verified:
- isinstance(load_config_readonly(), dict) is True
- timeout/stale resolutions correct
- load_config() still returns isolated mutable deepcopies
- tests/hermes_cli/test_config*.py / test_timeouts.py: 102/102 pass
- tests/cli/ + tests/agent/test_auxiliary_client.py: 883/883 pass
Teknium
3b220cb76b