Four deferrals following the established truthy-skip / PEP 562
lazy-load patterns (PRs #22681/#22859 lineage). Rebased over #74194,
which independently landed the browser_tool half of this work — that
file is dropped here; the remaining four modules are untouched by it:
- tools/vision_tools.py: defer agent.auxiliary_client
(credential_pool -> hermes_cli.auth -> httpx -> rich, ~50 ms) to
first vision handler call. async_call_llm /
extract_content_or_reasoning stay patchable module attributes;
injected test mocks win over the loader.
- agent/model_metadata.py: defer 'requests' (+urllib3, ~27 ms of the
'import cli' waterfall) to the fetch functions. PEP 562 __getattr__
keeps patch('agent.model_metadata.requests.get') working.
- tools/browser_supervisor.py: websockets (~22 ms) imports on first
CDP connect; ClientConnection type under TYPE_CHECKING.
- cron/jobs.py: croniter (~15 ms) resolves on first cron-expression
use; HAS_CRONITER stays monkeypatchable (None = unprobed sentinel).
A/B vs current main incl. #74194 (median of 7, cold subprocess):
import cli 147 -> 132 ms (-10%)
import model_tools 244 -> 224 ms (-8%)
import run_agent 264 -> 244 ms (-8%)
Lazy-verify: importing the four modules no longer pulls requests /
croniter / websockets into sys.modules. 369 targeted tests green
post-rebase.