Codex discovery surfaced every `~/.codex/hooks/*.{ts,js}` file as an OMP
hook (silently defaulting untyped names to `pre:<basename>`), and
`discoverExtensionPaths` then handed those paths to `loadExtension` for
dynamic import. A standalone Codex hook script with a top-level
`process.exit(0)` terminated the host CLI cleanly — `try/catch` around
`await import()` cannot intercept a synchronous exit, so OMP died at the
`loadExtensions:start` startup marker with no error surface.
Two-layer fix:
- `packages/coding-agent/src/extensibility/utils.ts`: new
`withExitGuard` helper patches `process.exit` for the duration of a
guarded callback so an exit raises `ExtensionExitError` instead of
terminating the process; nested and concurrent guards restore correctly
via depth counter.
- `extensibility/extensions/loader.ts`, `extensibility/hooks/loader.ts`,
and `extensibility/plugins/manager.ts` wrap their dynamic-import sites
in `withExitGuard` so the existing per-module `try/catch` records the
intercepted exit as a load error and OMP keeps starting.
- `discovery/codex.ts:loadHooks` no longer treats arbitrary files as
OMP hooks: only `pre-<tool>.{ts,js}` and `post-<tool>.{ts,js}` are
registered. Files like `memory-bank-reminder.ts` are silently skipped
rather than imported as extension factories.
Adds regression coverage:
- `test/extension-loader-process-exit.test.ts` — `loadExtensions` /
`loadHooks` return errors and leave `process.exit` restored when a
module exits at import time; sibling modules still load.
- `test/discovery/codex-hooks-discovery.test.ts` — codex provider
registers `pre-*` / `post-*` files and drops everything else.
Fixes#3680
roboomp
500c39aa2e