## 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
`codex sandbox windows` previously did a one-shot spawn for all
commands.
This change uses the `unified_exec` session to spawn long-lived
processes instead, and implements a simple bridge to forward stdin to
the spawned session and stdout/stderr from the spawned session back to
the caller.
It also fixes a bug with the new shared spawn context code where the
"no-network env" was being applied to both elevated and unelevated
sandbox spawns. It should only be applied for the unelevated sandbox
because the elevated one uses firewall rules instead of an env-based
network suppression strategy.
## Summary
This PR adds `CodexAuth::AgentIdentity` as an explicit auth mode.
An AgentIdentity auth record is a standalone `auth.json` mode. When
`AuthManager::auth().await` loads that mode, it registers one
process-scoped task and stores it in runtime-only state on the auth
value. Header creation stays synchronous after that because the task is
initialized before callers receive the auth object.
This PR also removes the old feature flag path. AgentIdentity is
selected by explicit auth mode, not by a hidden flag or lazy mutation of
ChatGPT auth records.
Reference old stack: https://github.com/openai/codex/pull/17387/changes
## Design Decisions
- AgentIdentity is a real auth enum variant because it can be the only
credential in `auth.json`.
- The process task is ephemeral runtime state. It is not serialized and
is not stored in rollout/session data.
- Account/user metadata needed by existing Codex backend checks lives on
the AgentIdentity record for now.
- `is_chatgpt_auth()` remains token-specific.
- `uses_codex_backend()` is the broader predicate for ChatGPT-token auth
and AgentIdentity auth.
## Stack
1. https://github.com/openai/codex/pull/18757: full revert
2. https://github.com/openai/codex/pull/18871: isolated Agent Identity
crate
3. This PR: explicit AgentIdentity auth mode and startup task allocation
4. https://github.com/openai/codex/pull/18811: migrate Codex backend
auth callsites through AuthProvider
5. https://github.com/openai/codex/pull/18904: accept AgentIdentity JWTs
and load `CODEX_AGENT_IDENTITY`
## Testing
Tests: targeted Rust checks, cargo-shear, Bazel lock check, and CI.