Files
codex/codex-rs/exec-server/src
jif 13ba8058f2 Resolve selected capability roots without starting executors (#31581)
## Why

A thread can select skill roots that live in an executor environment.
`skills/list` needs a passive snapshot of the roots that are usable now:
it must not start an executor, wait for recovery, or reconnect a failed
environment.

The initial implementation checked the immutable first startup result.
After a successful connection later entered recovery or failed, that
result still looked successful. A read-only catalog request could then
wait for recovery or trigger a new connection while reading the
filesystem.

## What

- inspect readiness from the current exec-server connection state
- return roots only while their environment can serve a request
immediately
- omit environments that have not started, are connecting, or are
recovering
- return warnings for missing environments and terminal connection
failures
- add a fail-fast filesystem view that never starts, waits for, or
reconnects an environment
- expose the passive selected-root snapshot through `CodexThread`

## Behavior

- Local and currently connected environments are ready.
- Starting and recovering environments are omitted without a warning so
callers can retry later.
- Missing and terminally failed environments are omitted with a warning.
- A disconnect between readiness inspection and filesystem access fails
promptly instead of crossing into the normal recovery path.
- Normal model-turn and execution paths keep their existing reconnect
behavior.

## Design

The recovery policy is private to the exec-server client. Callers choose
the explicit fail-fast filesystem method; the existing client and
filesystem APIs remain reconnecting. This keeps the passive contract at
the transport boundary instead of plumbing timeout or retry flags
through the skills stack.

## Coverage

- a lazy stdio environment stays unstarted during passive inspection
- missing and terminally failed environments surface warnings
- a real websocket disconnect proves current readiness drops, a
previously acquired fail-fast filesystem handle returns promptly, and
readiness returns after recovery

## Scope

This PR only provides passive readiness and fail-fast filesystem
primitives. It does not add app-server API fields or notifications.

## Stack

- #31582 uses these primitives for experimental thread-scoped
`skills/list`.
- #30228 adds targeted invalidation notifications.
2026-07-09 11:17:05 +01:00
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2026-07-08 19:46:18 +01:00