Files
codex/codex-rs/core
Michael Bolin 6afcf26d5d core: route Responses API through system proxy (#31335)
## Why

`features.respect_system_proxy` already routes authentication traffic
through the OS proxy APIs, but it does not affect the primary inference
path. That leaves users behind OS-managed proxies unable to send normal
Responses API requests even after login succeeds.

This PR is the first product-path migration onto the route-aware
transport introduced in #31323 and refined in #31331. It also
establishes the construction pattern for later migrations: the effective
feature state is resolved once into a required HTTP client factory
rather than represented by an optional per-call setting.

The scope remains limited to the two HTTP Responses endpoints;
WebSockets, model discovery, memories, realtime, and file uploads remain
follow-up migrations.

## What changed

- Replace the optional proxy marker with an explicit
`OutboundProxyPolicy::{ReqwestDefault, RespectSystemProxy}` and a
required `HttpClientFactory`. The policy has no default, and the
lower-level route-aware reqwest builder is now private.
- Have `Config` construct the factory from the effective feature state
and require every `ModelClient` constructor to receive it. There is no
optional setter or implicit `None` fallback.
- Build HTTP clients for `/responses` and `/responses/compact` with
`ClientRouteClass::Api`, using the complete destination URL so PAC rules
can make URL-specific decisions.
- Layer route-aware selection onto Codex's existing default headers,
Cloudflare cookie store, custom CA handling, and sandbox no-proxy
behavior.
- Add an integration test that loads `features.respect_system_proxy`
through `config.toml`, creates a real Codex session, and verifies that
both a normal Responses turn and remote compaction reach an isolated
local proxy.

## Review guide

1. `http-client/src/outbound_proxy.rs` defines the mandatory
policy/factory boundary and keeps route resolution private.
2. `core/src/config/mod.rs`, `core/src/session/session.rs`, and
`core/src/client.rs` show the compile-time invariant: effective config
creates the factory, and `ModelClient` cannot be constructed without
one.
3. `login/src/auth/default_client.rs` preserves existing default-client
behavior while accepting the required factory for migrated routes.
4. `core/src/client.rs` switches only streaming Responses and remote
compaction HTTP transports to the API route class.
5. `core/tests/suite/responses_api_system_proxy.rs` is the behavioral
regression boundary. Its Linux subprocess deliberately sets the CGI
marker that disables reqwest's implicit environment-proxy handling, so
the test fails if session wiring or either Responses call site falls
back to the default client.

## Test plan

- `cargo check --tests -p codex-http-client -p codex-login -p
codex-core`
- `just test -p codex-login`
- `just test -p codex-core
respect_system_proxy_feature_resolves_enabled`
- Existing `compact_uses_bearer_after_agent_identity_session_fallback`
coverage passes with the new transport construction.
- New Linux integration coverage:
`responses_and_compact_use_enabled_system_proxy`
- `just bazel-lock-check`

---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/openai/codex/pull/31335).
* #31342
* __->__ #31335
2026-07-07 03:49:53 +00:00
..

codex-core

This crate implements the business logic for Codex. It is designed to be used by the various Codex UIs written in Rust.

Wine-exec integration tests

On x86-64 Linux, run the shared suite against the Windows exec server with bazel test //codex-rs/core:core-all-wine-exec-test.

Local execution targets the host OS, Docker targets Linux, and Wine exec targets Windows. Choose the skip macro by what the test depends on:

  • skip_if_target_windows!: Windows target behavior.
  • skip_if_host_windows!: Windows host constraints.
  • skip_if_remote!: Local-only test behavior.
  • skip_if_no_remote_env!: Remote-only test behavior.
  • skip_if_wine_exec!: Wine-specific runner debt.

Dependencies

Note that codex-core makes some assumptions about certain helper utilities being available in the environment. Currently, this support matrix is:

macOS

Expects /usr/bin/sandbox-exec to be present.

When using the workspace-write sandbox policy, the Seatbelt profile allows writes under the configured writable roots while keeping .git (directory or pointer file), the resolved gitdir: target, and .codex read-only.

Network access and filesystem read/write roots are controlled by SandboxPolicy. Seatbelt consumes the resolved policy and enforces it.

Seatbelt also keeps the legacy default preferences read access (user-preference-read) needed for cfprefs-backed macOS behavior.

Linux

Expects the binary containing codex-core to run the equivalent of codex sandbox when arg0 is codex-linux-sandbox. See the codex-arg0 crate for details.

Legacy SandboxPolicy / sandbox_mode configs are still supported on Linux. They can continue to use the legacy Landlock path when the split filesystem policy is sandbox-equivalent to the legacy model after cwd resolution. Split filesystem policies that need direct FileSystemSandboxPolicy enforcement, such as read-only or denied carveouts under a broader writable root, automatically route through bubblewrap. The legacy Landlock path is used only when the split filesystem policy round-trips through the legacy SandboxPolicy model without changing semantics. That includes overlapping cases like /repo = write, /repo/a = none, /repo/a/b = write, where the more specific writable child must reopen under a denied parent.

The Linux sandbox helper prefers the first bwrap found on PATH outside the current working directory whenever it is available. If bwrap is present but too old to support --argv0, the helper keeps using system bubblewrap and switches to a no---argv0 compatibility path for the inner re-exec. If bwrap is missing, it falls back to the bundled codex-resources/bwrap binary shipped with Codex and Codex surfaces a startup warning through its normal notification path instead of printing directly from the sandbox helper. Codex also surfaces a startup warning when bubblewrap cannot create user namespaces. WSL2 uses the normal Linux bubblewrap path. WSL1 is not supported for bubblewrap sandboxing because it cannot create the required user namespaces, so Codex rejects sandboxed shell commands that would enter the bubblewrap path before invoking bwrap.

Windows

Legacy SandboxPolicy / sandbox_mode configs are still supported on Windows. Legacy read-only and workspace-write policies imply full filesystem read access; exact readable roots are represented by split filesystem policies instead.

The elevated Windows sandbox also supports:

  • legacy ReadOnly and WorkspaceWrite behavior
  • split filesystem policies that need exact readable roots, exact writable roots, or extra read-only carveouts under writable roots
  • backend-managed system read roots required for basic execution, such as C:\Windows, C:\Program Files, C:\Program Files (x86), and C:\ProgramData, when a split filesystem policy requests platform defaults

The unelevated restricted-token backend still supports the legacy full-read Windows model for legacy ReadOnly and WorkspaceWrite behavior. It also supports a narrow split-filesystem subset: full-read split policies whose writable roots still match the legacy WorkspaceWrite root set, but add extra read-only carveouts under those writable roots.

New [permissions] / split filesystem policies remain supported on Windows only when they can be enforced directly by the selected Windows backend or round-trip through the legacy SandboxPolicy model without changing semantics. Policies that would require direct explicit unreadable carveouts (none) or reopened writable descendants under read-only carveouts still fail closed instead of running with weaker enforcement.

All Platforms

Expects the binary containing codex-core to simulate the virtual apply_patch CLI when arg1 is --codex-run-as-apply-patch. See the codex-arg0 crate for details.