## Why
The `PermissionProfile` migration needs app-server clients to see the
same constrained permission model that core is using at runtime. Before
this PR, thread lifecycle responses only exposed the legacy
`SandboxPolicy` shape, so clients still had to infer active permissions
from sandbox fields. That makes downstream resume, fork, and override
flows harder to make `PermissionProfile`-first.
External sandbox policies are intentionally excluded from this canonical
view. External enforcement cannot be round-tripped as a
`PermissionProfile`, and exposing a lossy root-write profile would let
clients accidentally change sandbox semantics if they echo the profile
back later.
## What changed
- Adds the app-server v2 `PermissionProfile` wire shape, including
filesystem permissions and glob scan depth metadata.
- Adds `PermissionProfileNetworkPermissions` so the profile response
does not expose active network state through the older
additional-permissions naming.
- Returns `permissionProfile` from thread start, resume, and fork
responses when the active sandbox can be represented as a
`PermissionProfile`.
- Keeps legacy `sandbox` in those responses for compatibility and
documents `permissionProfile` as canonical when present.
- Makes lifecycle `permissionProfile` nullable and returns `null` for
`ExternalSandbox` to avoid exposing a lossy profile.
- Regenerates the app-server JSON schema and TypeScript fixtures.
## Verification
- `cargo test -p codex-app-server-protocol`
- `cargo test -p codex-app-server
thread_response_permission_profile_omits_external_sandbox --
--nocapture`
- `cargo check --tests -p codex-analytics -p codex-exec -p codex-tui`
- `just fix -p codex-app-server-protocol -p codex-app-server -p
codex-analytics -p codex-exec -p codex-tui`
---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/openai/codex/pull/18278).
* #18279
* __->__ #18278
Addresses #17498
Problem: The TUI derived /status instruction source paths from the local
client environment, which could show stale <none> output or incorrect
paths when connected to a remote app server.
Solution: Add an app-server v2 instructionSources snapshot to thread
start/resume/fork responses, default it to an empty list when older
servers omit it, and render TUI /status from that server-provided
session data.
Additional context: The app-server field is intentionally named
instructionSources rather than AGENTS.md-specific terminology because
the loaded instruction sources can include global instructions, project
AGENTS.md files, AGENTS.override.md, user-defined instruction files, and
future dynamic sources.
Addresses #16781
Problem: `codex exec --ephemeral` backfilled empty `turn/completed`
items with `thread/read(includeTurns=true)`, which app-server rejects
for ephemeral threads.
This is a regression introduced in the recent conversion of "exec" to
use app server rather than call the core directly.
Solution: Skip turn-item backfill for ephemeral exec threads while
preserving the existing recovery path for non-ephemeral sessions.
Addresses #16560
Problem: `/status` stopped showing the source thread id in forked TUI
sessions after the app-server migration.
Solution: Carry fork source ids through app-server v2 thread data and
the TUI session adapter, and update TUI fixtures so `/status` matches
the old TUI behavior.
## Why
`codex-rs/exec/src/lib.rs` already keeps unit tests in a sibling
`lib_tests.rs` module so the implementation stays top-heavy and easier
to read. This applies that same layout to the rest of
`codex-rs/exec/src` so each production file keeps its entry points and
helpers ahead of test code.
## What
- Move inline unit tests out of `cli.rs`, `main.rs`,
`event_processor_with_human_output.rs`, and
`event_processor_with_jsonl_output.rs` into sibling `*_tests.rs` files.
- Keep test modules wired through `#[cfg(test)]` plus `#[path = "..."]
mod tests;`, matching the `lib.rs` pattern.
- Preserve the existing test coverage and assertions while making this a
source-layout-only refactor.
## Verification
- `cargo test -p codex-exec`
Michael Bolin