### Summary
* Added `mcpServer/oauthLogin` in app server for supporting in session
MCP server login
* Added `McpServerOauthLoginParams` and `McpServerOauthLoginResponse` to
support above method with response returning the auth URL for consumer
to open browser or display accordingly.
* Added `McpServerOauthLoginCompletedNotification` which the app server
would emit on MCP server login success or failure (i.e. timeout).
* Refactored rmcp-client oath_login to have the ability on starting a
auth server which the codex_message_processor uses for in-session auth.
This introduces a new feature to Codex when it operates as an MCP
_client_ where if an MCP _server_ replies that it has an entry named
`"codex/sandbox-state"` in its _server capabilities_, then Codex will
send it an MCP notification with the following structure:
```json
{
"method": "codex/sandbox-state/update",
"params": {
"sandboxPolicy": {
"type": "workspace-write",
"network-access": false,
"exclude-tmpdir-env-var": false
"exclude-slash-tmp": false
},
"codexLinuxSandboxExe": null,
"sandboxCwd": "/Users/mbolin/code/codex2"
}
}
```
or with whatever values are appropriate for the initial `sandboxPolicy`.
**NOTE:** Codex _should_ continue to send the MCP server notifications
of the same format if these things change over the lifetime of the
thread, but that isn't wired up yet.
The result is that `shell-tool-mcp` can consume these values so that
when it calls `codex_core::exec::process_exec_tool_call()` in
`codex-rs/exec-server/src/posix/escalate_server.rs`, it is now sure to
call it with the correct values (whereas previously we relied on
hardcoded values).
While I would argue this is a supported use case within the MCP
protocol, the `rmcp` crate that we are using today does not support
custom notifications. As such, I had to patch it and I submitted it for
review, so hopefully it will be accepted in some form:
https://github.com/modelcontextprotocol/rust-sdk/pull/556
To test out this change from end-to-end:
- I ran `cargo build` in `~/code/codex2/codex-rs/exec-server`
- I built the fork of Bash in `~/code/bash/bash`
- I added the following to my `~/.codex/config.toml`:
```toml
# Use with `codex --disable shell_tool`.
[mcp_servers.execshell]
args = ["--bash", "/Users/mbolin/code/bash/bash"]
command = "/Users/mbolin/code/codex2/codex-rs/target/debug/codex-exec-mcp-server"
```
- From `~/code/codex2/codex-rs`, I ran `just codex --disable shell_tool`
- When the TUI started up, I verified that the sandbox mode is
`workspace-write`
- I ran `/mcp` to verify that the shell tool from the MCP is there:
<img width="1387" height="1400" alt="image"
src="https://github.com/user-attachments/assets/1a8addcc-5005-4e16-b59f-95cfd06fd4ab"
/>
- Then I asked it:
> what is the output of `gh issue list`
because this should be auto-approved with our existing dummy policy:
https://github.com/openai/codex/blob/af63e6eccc35783f1bf4dca3c61adb090efb6b8a/codex-rs/exec-server/src/posix.rs#L157-L164
And it worked:
<img width="1387" height="1400" alt="image"
src="https://github.com/user-attachments/assets/7568d2f7-80da-4d68-86d0-c265a6f5e6c1"
/>
## What?
Fixes MCP server initialization failures on Windows when using
script-based tools like `npx`, `pnpm`, and `yarn` that rely on
`.cmd`/`.bat` files rather than `.exe` binaries.
Fixes#2945
## Why?
Windows users encounter "program not found" errors when configuring MCP
servers with commands like `npx` in their `~/.codex/config.toml`. This
happens because:
- Tools like `npx` are batch scripts (`npx.cmd`) on Windows, not
executable binaries
- Rust's `std::process::Command` bypasses the shell and cannot execute
these scripts directly
- The Windows shell normally handles this by checking `PATHEXT` for
executable extensions
Without this fix, Windows users must specify full paths or add `.cmd`
extensions manually, which breaks cross-platform compatibility.
## How?
Added platform-specific program resolution using the `which` crate to
find the correct executable path:
- **Windows**: Resolves programs through PATH/PATHEXT to find
`.cmd`/`.bat` scripts
- **Unix**: Returns the program unchanged (no-op, as Unix handles
scripts natively)
### Changes
- Added `which = "6"` dependency to `mcp-client/Cargo.toml`
- Implemented `program_resolver` module in `mcp_client.rs` with
platform-specific resolution
- Added comprehensive tests for both Windows and Unix behavior
### Testing
Added platform-specific tests to verify:
- Unix systems execute scripts without extensions
- Windows fails without proper extensions
- Windows succeeds with explicit extensions
- Cross-platform resolution enables successful execution
**Tested on:**
- Windows 11 (NT 10.0.26100.0 x64)
- PowerShell 5.1 & 7+, CMD, Git Bash
- MCP servers: playwright, context7, supabase
- WSL (verified no regression)
**Local checks passed:**
```bash
cargo test && cargo clippy --tests && cargo fmt -- --config imports_granularity=Item
```
### Results
**Before:**
```
🖐 MCP client for `playwright` failed to start: program not found
```
**After:**
```
🖐 MCP client for `playwright` failed to start: request timed out
```
Windows users can now use simple commands like `npx` in their config
without specifying full paths or extensions. The timeout issue is a
separate concern that will be addressed in a follow-up PR.
---------
Co-authored-by: Eric Traut <etraut@openai.com>
# Preserve PATH precedence & fix Windows MCP env propagation
## Problem & intent
Preserve user PATH precedence and reduce Windows setup friction for MCP
servers by avoiding PATH reordering and ensuring Windows child processes
receive essential env vars.
- Addresses: #4180#5225#2945#3245#3385#2892#3310#3457#4370
- Supersedes: #4182, #3866, #3828 (overlapping/inferior once this
merges)
- Notes: #2626 / #2646 are the original PATH-mutation sources being
corrected.
---
## Before / After
**Before**
- PATH was **prepended** with an `apply_patch` helper dir (Rust + Node
wrapper), reordering tools and breaking virtualenvs/shims on
macOS/Linux.
- On Windows, MCP servers missed core env vars and often failed to start
without explicit per-server env blocks.
**After**
- Helper dir is **appended** to PATH (preserves user/tool precedence).
- Windows MCP child env now includes common core variables and mirrors
`PATH` → `Path`, so typical CLIs/plugins work **without** per-server env
blocks.
---
## Scope of change
### `codex-rs/arg0/src/lib.rs`
- Append temp/helper dir to `PATH` instead of prepending.
### `codex-cli/bin/codex.js`
- Mirror the same append behavior for the Node wrapper.
### `codex-rs/rmcp-client/src/utils.rs`
- Expand Windows `DEFAULT_ENV_VARS` (e.g., `COMSPEC`, `SYSTEMROOT`,
`PROGRAMFILES*`, `APPDATA`, etc.).
- Mirror `PATH` → `Path` for Windows child processes.
- Small unit test; conditional `mut` + `clippy` cleanup.
---
## Security effects
No broadened privileges. Only environment propagation for well-known
Windows keys on stdio MCP child processes. No sandbox policy changes and
no network additions.
---
## Testing evidence
**Static**
- `cargo fmt`
- `cargo clippy -p codex-arg0 -D warnings` → **clean**
- `cargo clippy -p codex-rmcp-client -D warnings` → **clean**
- `cargo test -p codex-rmcp-client` → **13 passed**
**Manual**
- Local verification on Windows PowerShell 5/7 and WSL (no `unused_mut`
warnings on non-Windows targets).
---
## Checklist
- [x] Append (not prepend) helper dir to PATH in Rust and Node wrappers
- [x] Windows MCP child inherits core env vars; `PATH` mirrored to
`Path`
- [x] `cargo fmt` / `clippy` clean across touched crates
- [x] Unit tests updated/passing where applicable
- [x] Cross-platform behavior preserved (macOS/Linux PATH precedence
intact)
It's pretty amazing we have gotten here without the ability for the
model to see image content from MCP tool calls.
This PR builds off of 4391 and fixes#4819. I would like @KKcorps to get
adequete credit here but I also want to get this fix in ASAP so I gave
him a week to update it and haven't gotten a response so I'm going to
take it across the finish line.
This test highlights how absured the current situation is. I asked the
model to read this image using the Chrome MCP
<img width="2378" height="674" alt="image"
src="https://github.com/user-attachments/assets/9ef52608-72a2-4423-9f5e-7ae36b2b56e0"
/>
After this change, it correctly outputs:
> Captured the page: image dhows a dark terminal-style UI labeled
`OpenAI Codex (v0.0.0)` with prompt `model: gpt-5-codex medium` and
working directory `/codex/codex-rs`
(and more)
Before this change, it said:
> Took the full-page screenshot you asked for. It shows a long,
horizontally repeating pattern of stylized people in orange, light-blue,
and mustard clothing, holding hands in alternating poses against a white
background. No text or other graphics-just rows of flat illustration
stretching off to the right.
Without this change, the Figma, Playwright, Chrome, and other visual MCP
servers are pretty much entirely useless.
I tested this change with the openai respones api as well as a third
party completions api
Follow-up PR to #5569. Add Keyring Support for Auth Storage in Codex CLI
as well as a hybrid mode (default to persisting in keychain but fall
back to file when unavailable.)
It also refactors out the keyringstore implementation from rmcp-client
[here](https://github.com/openai/codex/blob/main/codex-rs/rmcp-client/src/oauth.rs)
to a new keyring-store crate.
There will be a follow-up that picks the right credential mode depending
on the config, instead of hardcoding `AuthCredentialsStoreMode::File`.
This makes stdio mcp servers more flexible by allowing users to specify
the cwd to run the server command from and adding additional environment
variables to be passed through to the server.
Example config using the test server in this repo:
```toml
[mcp_servers.test_stdio]
cwd = "/Users/<user>/code/codex/codex-rs"
command = "cargo"
args = ["run", "--bin", "test_stdio_server"]
env_vars = ["MCP_TEST_VALUE"]
```
@bolinfest I know you hate these env var tests but let's roll with this
for now. I may take a stab at the env guard + serial macro at some
point.
This adds two new config fields to streamable http mcp servers:
`http_headers`: a map of key to value
`env_http_headers` a map of key to env var which will be resolved at
request time
All headers will be passed to all MCP requests to that server just like
authorization headers.
There is a test ensuring that headers are not passed to other servers.
Fixes#5180
1. If Codex detects that a `codex mcp add -url …` server supports oauth,
it will auto-initiate the login flow.
2. If the TUI starts and a MCP server supports oauth but isn't logged
in, it will give the user an explicit warning telling them to log in.
This adds a queryable auth status for MCP servers which is useful:
1. To determine whether a streamable HTTP server supports auth or not
based on whether or not it supports RFC 8414-3.2
2. Allow us to build a better user experience on top of MCP status
This lets users/companies explicitly choose whether to force/disallow
the keyring/fallback file storage for mcp credentials.
People who develop with Codex will want to use this until we sign
binaries or else each ad-hoc debug builds will require keychain access
on every build. I don't love this and am open to other ideas for how to
handle that.
```toml
mcp_oauth_credentials_store = "auto"
mcp_oauth_credentials_store = "file"
mcp_oauth_credentials_store = "keyrung"
```
Defaults to `auto`
`http_config.auth_header` automatically added `Bearer `. By adding it
ourselves, we were sending `Bearer Bearer <token>`.
I confirmed that the GitHub MCP initialization 400s before and works
now.
I also optimized the oauth flow to not check the keyring if you
explicitly pass in a bearer token.
This PR adds oauth login support to streamable http servers when
`experimental_use_rmcp_client` is enabled.
This PR is large but represents the minimal amount of work required for
this to work. To keep this PR smaller, login can only be done with
`codex mcp login` and `codex mcp logout` but it doesn't appear in `/mcp`
or `codex mcp list` yet. Fingers crossed that this is the last large MCP
PR and that subsequent PRs can be smaller.
Under the hood, credentials are stored using platform credential
managers using the [keyring crate](https://crates.io/crates/keyring).
When the keyring isn't available, it falls back to storing credentials
in `CODEX_HOME/.credentials.json` which is consistent with how other
coding agents handle authentication.
I tested this on macOS, Windows, WSL (ubuntu), and Linux. I wasn't able
to test the dbus store on linux but did verify that the fallback works.
One quirk is that if you have credentials, during development, every
build will have its own ad-hoc binary so the keyring won't recognize the
reader as being the same as the write so it may ask for the user's
password. I may add an override to disable this or allow
users/enterprises to opt-out of the keyring storage if it causes issues.
<img width="5064" height="686" alt="CleanShot 2025-09-30 at 19 31 40"
src="https://github.com/user-attachments/assets/9573f9b4-07f1-4160-83b8-2920db287e2d"
/>
<img width="745" height="486" alt="image"
src="https://github.com/user-attachments/assets/9562649b-ea5f-4f22-ace2-d0cb438b143e"
/>
This PR adds support for streamable HTTP MCP servers when the
`experimental_use_rmcp_client` is enabled.
To set one up, simply add a new mcp server config with the url:
```
[mcp_servers.figma]
url = "http://127.0.0.1:3845/mcp"
```
It also supports an optional `bearer_token` which will be provided in an
authorization header. The full oauth flow is not supported yet.
The config parsing will throw if it detects that the user mixed and
matched config fields (like command + bearer token or url + env).
The best way to review it is to review `core/src` and then
`rmcp-client/src/rmcp_client.rs` first. The rest is tests and
propagating the `Transport` struct around the codebase.
Example with the Figma MCP:
<img width="5084" height="1614" alt="CleanShot 2025-09-26 at 13 35 40"
src="https://github.com/user-attachments/assets/eaf2771e-df3e-4300-816b-184d7dec5a28"
/>
The [official Rust
SDK](https://github.com/modelcontextprotocol/rust-sdk/tree/57fc428c578a1a3fe851ee0838bf068bda120eb3)
has come a long way since we first started our mcp client implementation
5 months ago and, today, it is much more complete than our own
stdio-only implementation.
This PR introduces a new config flag `experimental_use_rmcp_client`
which will use a new mcp client powered by the sdk instead of our own.
To keep this PR simple, I've only implemented the same stdio MCP
functionality that we had but will expand on it with future PRs.
---------
Co-authored-by: pakrym-oai <pakrym@openai.com>
Shijie Rao ·
Michael Bolin ·
Jeremy Rose ·
Lael ·
Joonsoo Lee ·
Gabriel Peal ·
Curt ·
Celia Chen ·