## Why
`built_tools` runs for every sampling request, and local plugin
discovery was repeatedly rereading plugin manifests, skills, MCP
configuration, and app declarations to build the same tool-suggest
metadata.
That source-derived metadata is stable until the existing plugin manager
reloads its cache. Runtime eligibility still needs to reflect the
current install, disable, policy, app-overlap, and authentication state.
## What changed
- Add a bounded, in-memory tool-suggest metadata cache owned by
`PluginsManager`.
- Key cached metadata by plugin identity and source, while applying
authentication routing each time the metadata is projected.
- Invalidate the metadata alongside the existing loaded-plugin cache,
including its normal configuration, marketplace refresh, and
remote-installed-plugin invalidation paths.
- Guard against an in-flight load repopulating stale metadata after
invalidation.
- Keep marketplace membership and all runtime eligibility filtering live
rather than introducing a separate catalog or revision model.
## Impact
Repeated sampling requests reuse already-loaded plugin capability
metadata while retaining the existing plugin-manager lifecycle as the
single freshness boundary.
## Validation
- `just test -p codex-core-plugins` — 252 passed
- Added focused coverage for cache invalidation and authentication
reprojection.
Matthew ZengandGitHub
a52a3b5197