codex

fix(app-server): set originator header from initialize JSON-RPC request (#8873 )

**Motivation**
The `originator` header is important for codex-backend’s Responses API
proxy because it identifies the real end client (codex cli, codex vscode
extension, codex exec, future IDEs) and is used to categorize requests
by client for our enterprise compliance API.

Today the `originator` header is set by either:
- the `CODEX_INTERNAL_ORIGINATOR_OVERRIDE` env var (our VSCode extension
does this)
- calling `set_default_originator()` which sets a global immutable
singleton (`codex exec` does this)

For `codex app-server`, we want the `initialize` JSON-RPC request to set
that header because it is a natural place to do so. Example:
```json
{
  "method": "initialize",
  "id": 0,
  "params": {
    "clientInfo": {
      "name": "codex_vscode",
      "title": "Codex VS Code Extension",
      "version": "0.1.0"
    }
  }
}
```
and when app-server receives that request, it can call
`set_default_originator()`. This is a much more natural interface than
asking third party developers to set an env var.

One hiccup is that `originator()` reads the global singleton and locks
in the value, preventing a later `set_default_originator()` call from
setting it. This would be fine but is brittle, since any codepath that
calls `originator()` before app-server can process an `initialize`
JSON-RPC call would prevent app-server from setting it. This was
actually the case with OTEL initialization which runs on boot, but I
also saw this behavior in certain tests.

Instead, what we now do is:
- [unchanged] If `CODEX_INTERNAL_ORIGINATOR_OVERRIDE` env var is set,
`originator()` would return that value and `set_default_originator()`
with some other value does NOT override it.
- [new] If no env var is set, `originator()` would return the default
value which is `codex_cli_rs` UNTIL `set_default_originator()` is called
once, in which case it is set to the new value and becomes immutable.
Later calls to `set_default_originator()` returns
`SetOriginatorError::AlreadyInitialized`.

**Other notes**
- I updated `codex_core::otel_init::build_provider` to accepts a service
name override, and app-server sends a hardcoded `codex_app_server`
service name to distinguish it from `codex_cli_rs` used by default (e.g.
TUI).

**Next steps**
- Update VSCE to set the proper value for `clientInfo.name` on
`initialize` and drop the `CODEX_INTERNAL_ORIGINATOR_OVERRIDE` env var.
- Delete support for `CODEX_INTERNAL_ORIGINATOR_OVERRIDE` in codex-rs.

Owen Lin · 2026-01-09 08:17:13 -08:00

ea56186c2b

[chore] move app server tests from chat completion to responses (#8939 )

We are deprecating chat completions. Move all app server tests from chat
completion to responses.

Celia Chen · 2026-01-08 22:27:55 +00:00

be4364bb80

feat: fork conversation/thread (#8866 )

## Summary
- add thread/conversation fork endpoints to the protocol (v1 + v2)
- implement fork handling in app-server using thread manager and config
overrides
- add fork coverage in app-server tests and document `thread/fork` usage

Anton Panasenko · 2026-01-08 12:54:20 -08:00

41a317321d

[fix] app server flaky send_messages test (#8874 )

Fix flakiness of CI test:
https://github.com/openai/codex/actions/runs/20350530276/job/58473691434?pr=8282

This PR does two things:
1. move the flakiness test to use responses API instead of chat
completion API
2. make mcp_process agnostic to the order of
responses/notifications/requests that come in, by buffering messages not
read

Celia Chen · 2026-01-08 20:41:21 +00:00

051bf81df9

[fix] app server flaky thread/resume tests (#8870 )

Fix flakiness of CI tests:
https://github.com/openai/codex/actions/runs/20350530276/job/58473691443?pr=8282

This PR does two things:
1. test with responses API instead of chat completions API in
thread_resume tests;
2. have a new responses API fixture that mocks out arbitrary numbers of
responses API calls (including no calls) and have the same repeated
response.

Tested by CI

Celia Chen · 2026-01-08 10:17:05 -08:00

c4af304c77

feat: add list loaded threads to app server (#8902 )

jif-oai · 2026-01-08 17:48:20 +00:00

5b7707dfb1

Fix app-server write_models_cache to treat models with less priority number as higher priority. (#8844 )

Rank models with p0 higher than p1. This shouldn't result in any
behavioral changes. Just reordering.

Ahmed Ibrahim · 2026-01-07 11:22:13 -08:00

4c9b4b684f

Merge Modelfamily into modelinfo (#8763 )

- Merge ModelFamily into ModelInfo
- Remove logic for adding instructions to apply patch
- Add compaction limit and visible context window to `ModelInfo`

Ahmed Ibrahim · 2026-01-07 10:35:09 -08:00

9179c9deac

chore: unify conversation with thread name (#8830 )

Done and verified by Codex + refactor feature of RustRover

jif-oai · 2026-01-07 17:04:53 +00:00

116059c3a0

feat(app-server): thread/rollback API (#8454 )

Add `thread/rollback` to app-server to support IDEs undo-ing the last N
turns of a thread.

For context, an IDE partner will be supporting an "undo" capability
where the IDE (the app-server client) will be responsible for reverting
the local changes made during the last turn. To support this well, we
also need a way to drop the last turn (or more generally, the last N
turns) from the agent's context. This is what `thread/rollback` does.

**Core idea**: A Thread rollback is represented as a persisted event
message (EventMsg::ThreadRollback) in the rollout JSONL file, not by
rewriting history. On resume, both the model's context (core replay) and
the UI turn list (app-server v2's thread history builder) apply these
markers so the pruned history is consistent across live conversations
and `thread/resume`.

Implementation notes:
- Rollback only affects agent context and appends to the rollout file;
clients are responsible for reverting files on disk.
- If a thread rollback is currently in progress, subsequent
`thread/rollback` calls are rejected.
- Because we use `CodexConversation::submit` and codex core tracks
active turns, returning an error on concurrent rollbacks is communicated
via an `EventMsg::Error` with a new variant
`CodexErrorInfo::ThreadRollbackFailed`. app-server watches for that and
sends the BAD_REQUEST RPC response.

Tests cover thread rollbacks in both core and app-server, including when
`num_turns` > existing turns (which clears all turns).

**Note**: this explicitly does **not** behave like `/undo` which we just
removed from the CLI, which does the opposite of what `thread/rollback`
does. `/undo` reverts local changes via ghost commits/snapshots and does
not modify the agent's context / conversation history.

Owen Lin · 2026-01-06 21:23:48 +00:00

8b7ec31ba7

feat: introduce codex-utils-cargo-bin as an alternative to assert_cmd::Command (#8496 )

This PR introduces a `codex-utils-cargo-bin` utility crate that
wraps/replaces our use of `assert_cmd::Command` and
`escargot::CargoBuild`.

As you can infer from the introduction of `buck_project_root()` in this
PR, I am attempting to make it possible to build Codex under
[Buck2](https://buck2.build) as well as `cargo`. With Buck2, I hope to
achieve faster incremental local builds (largely due to Buck2's
[dice](https://buck2.build/docs/insights_and_knowledge/modern_dice/)
build strategy, as well as benefits from its local build daemon) as well
as faster CI builds if we invest in remote execution and caching.

See
https://buck2.build/docs/getting_started/what_is_buck2/#why-use-buck2-key-advantages
for more details about the performance advantages of Buck2.

Buck2 enforces stronger requirements in terms of build and test
isolation. It discourages assumptions about absolute paths (which is key
to enabling remote execution). Because the `CARGO_BIN_EXE_*` environment
variables that Cargo provides are absolute paths (which
`assert_cmd::Command` reads), this is a problem for Buck2, which is why
we need this `codex-utils-cargo-bin` utility.

My WIP-Buck2 setup sets the `CARGO_BIN_EXE_*` environment variables
passed to a `rust_test()` build rule as relative paths.
`codex-utils-cargo-bin` will resolve these values to absolute paths,
when necessary.


---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/openai/codex/pull/8496).
* #8498
* __->__ #8496

Michael Bolin · 2025-12-23 19:29:32 -08:00

e61bae12e3

Remove reasoning format (#8484 )

This isn't very useful parameter. 

logic:
```
if model puts `**` in their reasoning, trim it and visualize the header.
if couldn't trim: don't render
if model doesn't support: don't render
```

We can simplify to:
```
if could trim, visualize header.
if not, don't render
```

Ahmed Ibrahim · 2025-12-23 16:01:46 -08:00

40de81e7af

remove minimal client version (#8447 )

This isn't needed value by client

Ahmed Ibrahim · 2025-12-22 12:52:24 -08:00

6b2ef216f1

Rename OpenAI models to models manager (#8346 )

# External (non-OpenAI) Pull Request Requirements

Before opening this Pull Request, please read the dedicated
"Contributing" markdown file or your PR may be closed:
https://github.com/openai/codex/blob/main/docs/contributing.md

If your PR conforms to our contribution guidelines, replace this text
with a detailed and high quality description of your changes.

Include a link to a bug report or enhancement request.

Ahmed Ibrahim · 2025-12-19 16:20:05 -08:00

f0dc6fd3c7

feat: model picker (#8209 )

# External (non-OpenAI) Pull Request Requirements

Before opening this Pull Request, please read the dedicated
"Contributing" markdown file or your PR may be closed:
https://github.com/openai/codex/blob/main/docs/contributing.md

If your PR conforms to our contribution guidelines, replace this text
with a detailed and high quality description of your changes.

Include a link to a bug report or enhancement request.

Ahmed Ibrahim · 2025-12-17 16:12:35 -08:00

774bd9e432

fix: added test helpers for platform-specific paths (#7954 )

This addresses post-merge feedback from
https://github.com/openai/codex/pull/7856.

Michael Bolin · 2025-12-13 00:14:12 +00:00

b1905d3754

chores: models manager (#7937 )

Ahmed Ibrahim · 2025-12-12 18:59:39 +00:00

149696d959

Update Model Info (#7853 )

Ahmed Ibrahim · 2025-12-11 14:06:07 -08:00

b7fa7ca8e9

feat: add shell snapshot for shell command (#7786 )

jif-oai · 2025-12-11 13:46:43 +00:00

29381ba5c2

make model optional in config (#7769 )

- Make Config.model optional and centralize default-selection logic in
ModelsManager, including a default_model helper (with
codex-auto-balanced when available) so sessions now carry an explicit
chosen model separate from the base config.
- Resolve `model` once in `core` and `tui` from config. Then store the
state of it on other structs.
- Move refreshing models to be before resolving the default model

Ahmed Ibrahim · 2025-12-10 11:19:00 -08:00

cb9a189857

feat: update process ID for event handling (#7261 )

jif-oai · 2025-11-25 14:21:05 -08:00

28ff364c3a

feat[app-serve]: config management (#7241 )

jif-oai · 2025-11-25 09:29:38 +00:00

523b40a129

chore: add cargo-deny configuration (#7119 )

- add GitHub workflow running cargo-deny on push/PR
- document cargo-deny allowlist with workspace-dep notes and advisory
ignores
- align workspace crates to inherit version/edition/license for
consistent checks

Josh McKinney · 2025-11-24 12:22:18 -08:00

ec49b56874

[app-server] feat: expose gitInfo/cwd/etc. on Thread (#7060 )

Port the new additions from https://github.com/openai/codex/pull/6337 on
the legacy API to v2. Mainly need `gitInfo` and `cwd` for VSCE.

Owen Lin · 2025-11-21 10:37:12 -08:00

aa4e0d823e

Migrate coverage to shell_command (#7042 )

pakrym-oai · 2025-11-21 03:44:00 +00:00

767b66f407

feat: review in app server (#6613 )

jif-oai · 2025-11-18 21:58:54 +00:00

8ddae8cde3

[App-server] Implement account/read endpoint (#6336 )

This PR does two things:
1. add a new function in core that maps the core-internal plan type to
the external plan type;
2. implement account/read that get account status (v2 of
`getAuthStatus`).

Celia Chen · 2025-11-06 19:43:13 -08:00

e84e39940b

[app-server] feat: v2 Turn APIs (#6216 )

Implements:
```
turn/start
turn/interrupt
```

along with their integration tests. These are relatively light wrappers
around the existing core logic, and changes to core logic are minimal.

However, an improvement made for developer ergonomics:
- `turn/start` replaces both `SendUserMessage` (no turn overrides) and
`SendUserTurn` (can override model, approval policy, etc.)

Owen Lin · 2025-11-06 16:36:36 +00:00

6582554926

[App-server] Add account/login/cancel v2 endpoint (#6288 )

Add `account/login/cancel` v2 endpoint for auth. this is similar
implementation to `cancelLoginChatgpt` v1 endpoint.

Celia Chen · 2025-11-06 01:13:55 +00:00

229d18f4d2

[App-server] Implement v2 for account/login/start and account/login/completed (#6183 )

This PR implements `account/login/start` and `account/login/completed`.
Instead of having separate endpoints for login with chatgpt and api, we
have a single enum handling different login methods. For sync auth
methods like sign in with api key, we still send a `completed`
notification back to be compatible with the async login flow.

Celia Chen · 2025-11-05 13:52:50 -08:00

05f0b4f590

[app-server] feat: v2 Thread APIs (#6214 )

Implements:
```
thread/list
thread/start
thread/resume
thread/archive
```

along with their integration tests. These are relatively light wrappers
around the existing core logic, and changes to core logic are minimal.

However, an improvement made for developer ergonomics:
- `thread/start` and `thread/resume` automatically attaches a
conversation listener internally, so clients don't have to make a
separate `AddConversationListener` call like they do today.

For consistency, also updated `model/list` and `feedback/upload` (naming
conventions, list API params).

Owen Lin · 2025-11-05 20:28:43 +00:00

2ab1650d4d

[App-server] v2 for account/updated and account/logout (#6175 )

V2 for `account/updated` and `account/logout` for app server. correspond
to old `authStatusChange` and `LogoutChatGpt` respectively. Followup PRs
will make other v2 endpoints call `account/updated` instead of
`authStatusChange` too.

Celia Chen · 2025-11-03 22:01:33 -08:00

d3187dbc17

[Auth] Choose which auth storage to use based on config (#5792 )

This PR is a follow-up to #5591. It allows users to choose which auth
storage mode they want by using the new
`cli_auth_credentials_store_mode` config.

Celia Chen · 2025-10-27 19:41:49 -07:00

4a42c4e142

[Auth] Introduce New Auth Storage Abstraction for Codex CLI (#5569 )

This PR introduces a new `Auth Storage` abstraction layer that takes
care of read, write, and load of auth tokens based on the
AuthCredentialsStoreMode. It is similar to how we handle MCP client
oauth
[here](https://github.com/openai/codex/blob/main/codex-rs/rmcp-client/src/oauth.rs).
Instead of reading and writing directly from disk for auth tokens, Codex
CLI workflows now should instead use this auth storage using the public
helper functions.

This PR is just a refactor of the current code so the behavior stays the
same. We will add support for keyring and hybrid mode in follow-up PRs.

I have read the CLA Document and I hereby sign the CLA

Celia Chen · 2025-10-27 11:01:14 -07:00

eb5b1b627f

Add feedback upload request handling (#5682 )

Ahmed Ibrahim · 2025-10-27 05:53:39 +00:00

f178805252

[app-server] model/list API (#5382 )

Adds a `model/list` paginated API that returns the list of models
supported by Codex.

Owen Lin · 2025-10-21 11:15:17 -07:00

26f314904a

[app-server] read rate limits API (#5302 )

Adds a `GET account/rateLimits/read` API to app-server. This calls the
codex backend to fetch the user's current rate limits.

This would be helpful in checking rate limits without having to send a
message.

For calling the codex backend usage API, I generated the types and
manually copied the relevant ones into `codex-backend-openapi-types`.
It'll be nice to extend our internal openapi generator to support Rust
so we don't have to run these manual steps.

# External (non-OpenAI) Pull Request Requirements

Before opening this Pull Request, please read the dedicated
"Contributing" markdown file or your PR may be closed:
https://github.com/openai/codex/blob/main/docs/contributing.md

If your PR conforms to our contribution guidelines, replace this text
with a detailed and high quality description of your changes.

Owen Lin · 2025-10-20 14:11:54 -07:00

5c680c6587

chore: sandbox refactor 2 (#4653 )

Revert the revert and fix the UI issue

jif-oai · 2025-10-03 11:17:39 +01:00

69cb72f842

Revert "chore: sanbox extraction" (#4626 )

Reverts openai/codex#4286

Ahmed Ibrahim · 2025-10-02 21:09:21 +00:00

ed5d656fa8

chore: sanbox extraction (#4286 )

# Extract and Centralize Sandboxing
- Goal: Improve safety and clarity by centralizing sandbox planning and
execution.
  - Approach:
- Add planner (ExecPlan) and backend registry (Direct/Seatbelt/Linux)
with run_with_plan.
- Refactor codex.rs to plan-then-execute; handle failures/escalation via
the plan.
- Delegate apply_patch to the codex binary and run it with an empty env
for determinism.

jif-oai · 2025-10-01 12:05:12 +01:00

b8195a17e5

fix: remove mcp-types from app server protocol (#4537 )

We continue the separation between `codex app-server` and `codex
mcp-server`.

In particular, we introduce a new crate, `codex-app-server-protocol`,
and migrate `codex-rs/protocol/src/mcp_protocol.rs` into it, renaming it
`codex-rs/app-server-protocol/src/protocol.rs`.

Because `ConversationId` was defined in `mcp_protocol.rs`, we move it
into its own file, `codex-rs/protocol/src/conversation_id.rs`, and
because it is referenced in a ton of places, we have to touch a lot of
files as part of this PR.

We also decide to get away from proper JSON-RPC 2.0 semantics, so we
also introduce `codex-rs/app-server-protocol/src/jsonrpc_lite.rs`, which
is basically the same `JSONRPCMessage` type defined in `mcp-types`
except with all of the `"jsonrpc": "2.0"` removed.

Getting rid of `"jsonrpc": "2.0"` makes our serialization logic
considerably simpler, as we can lean heavier on serde to serialize
directly into the wire format that we use now.

Michael Bolin · 2025-10-01 02:16:26 +00:00

5881c0d6d4

fix: use macros to ensure request/response symmetry (#4529 )

Manually curating `protocol-ts/src/lib.rs` was error-prone, as expected.
I finally asked Codex to write some Rust macros so we can ensure that:

- For every variant of `ClientRequest` and `ServerRequest`, there is an
associated `params` and `response` type.
- All response types are included automatically in the output of `codex
generate-ts`.

Michael Bolin · 2025-09-30 18:06:05 -07:00

32853ecbc5

fix: separate codex mcp into codex mcp-server and codex app-server (#4471 )

This is a very large PR with some non-backwards-compatible changes.

Historically, `codex mcp` (or `codex mcp serve`) started a JSON-RPC-ish
server that had two overlapping responsibilities:

- Running an MCP server, providing some basic tool calls.
- Running the app server used to power experiences such as the VS Code
extension.

This PR aims to separate these into distinct concepts:

- `codex mcp-server` for the MCP server
- `codex app-server` for the "application server"

Note `codex mcp` still exists because it already has its own subcommands
for MCP management (`list`, `add`, etc.)

The MCP logic continues to live in `codex-rs/mcp-server` whereas the
refactored app server logic is in the new `codex-rs/app-server` folder.
Note that most of the existing integration tests in
`codex-rs/mcp-server/tests/suite` were actually for the app server, so
all the tests have been moved with the exception of
`codex-rs/mcp-server/tests/suite/mod.rs`.

Because this is already a large diff, I tried not to change more than I
had to, so `codex-rs/app-server/tests/common/mcp_process.rs` still uses
the name `McpProcess` for now, but I will do some mechanical renamings
to things like `AppServer` in subsequent PRs.

While `mcp-server` and `app-server` share some overlapping functionality
(like reading streams of JSONL and dispatching based on message types)
and some differences (completely different message types), I ended up
doing a bit of copypasta between the two crates, as both have somewhat
similar `message_processor.rs` and `outgoing_message.rs` files for now,
though I expect them to diverge more in the near future.

One material change is that of the initialize handshake for `codex
app-server`, as we no longer use the MCP types for that handshake.
Instead, we update `codex-rs/protocol/src/mcp_protocol.rs` to add an
`Initialize` variant to `ClientRequest`, which takes the `ClientInfo`
object we need to update the `USER_AGENT_SUFFIX` in
`codex-rs/app-server/src/message_processor.rs`.

One other material change is in
`codex-rs/app-server/src/codex_message_processor.rs` where I eliminated
a use of the `send_event_as_notification()` method I am generally trying
to deprecate (because it blindly maps an `EventMsg` into a
`JSONNotification`) in favor of `send_server_notification()`, which
takes a `ServerNotification`, as that is intended to be a custom enum of
all notification types supported by the app server. So to make this
update, I had to introduce a new variant of `ServerNotification`,
`SessionConfigured`, which is a non-backwards compatible change with the
old `codex mcp`, and clients will have to be updated after the next
release that contains this PR. Note that
`codex-rs/app-server/tests/suite/list_resume.rs` also had to be update
to reflect this change.

I introduced `codex-rs/utils/json-to-toml/src/lib.rs` as a small utility
crate to avoid some of the copying between `mcp-server` and
`app-server`.

Michael Bolin · 2025-09-30 07:06:18 +00:00

d9dbf48828

43 Commits