core-agent-ide/shell-tool-mcp
Michael Bolin d363a0968e
feat: codex-shell-tool-mcp (#7005)
This adds a GitHub workflow for building a new npm module we are
experimenting with that contains an MCP server for running Bash
commands. The new workflow, `shell-tool-mcp`, is a dependency of the
general `release` workflow so that we continue to use one version number
for all artifacts across the project in one GitHub release.

`.github/workflows/shell-tool-mcp.yml` is the primary workflow
introduced by this PR, which does the following:

- builds the `codex-exec-mcp-server` and `codex-execve-wrapper`
executables for both arm64 and x64 versions of Mac and Linux (preferring
the MUSL version for Linux)
- builds Bash (dynamically linked) for a [comically] large number of
platforms (both x64 and arm64 for most) with a small patch specified by
`shell-tool-mcp/patches/bash-exec-wrapper.patch`:
  - `debian-11`
  - `debian-12`
  - `ubuntu-20.04`
  - `ubuntu-22.04`
  - `ubuntu-24.04`
  - `centos-9`
  - `macos-13` (x64 only)
  - `macos-14` (arm64 only)
  - `macos-15` (arm64 only)
- builds the TypeScript for the [new] Node module declared in the
`shell-tool-mcp/` folder, which creates `bin/mcp-server.js`
- adds all of the native binaries to `shell-tool-mcp/vendor/` folder;
`bin/mcp-server.js` does a runtime check to determine which ones to
execute
- uses `npm pack` to create the `.tgz` for the module
- if `publish: true` is set, invokes the `npm publish` call with the
`.tgz`

The justification for building Bash for so many different operating
systems is because, since it is dynamically linked, we want to increase
our confidence that the version we build is compatible with the glibc
whatever OS we end up running on. (Note this is less of a concern with
`codex-exec-mcp-server` and `codex-execve-wrapper` on Linux, as they are
statically linked.)

This PR also introduces the code for the npm module in `shell-tool-mcp/`
(the proposed module name is `@openai/codex-shell-tool-mcp`). Initially,
I intended the module to be a single file of vanilla JavaScript (like
[`codex-cli/bin/codex.js`](ab5972d447/codex-cli/bin/codex.js)),
but some of the logic seemed a bit tricky, so I decided to port it to
TypeScript and add unit tests.

`shell-tool-mcp/src/index.ts` defines the `main()` function for the
module, which performs runtime checks to determine the clang triple to
find the path to the Rust executables within the `vendor/` folder
(`resolveTargetTriple()`). It uses a combination of `readOsRelease()`
and `resolveBashPath()` to determine the correct Bash executable to run
in the environment. Ultimately, it spawns a command like the following:

```
codex-exec-mcp-server \
    --execve codex-execve-wrapper \
    --bash custom-bash "$@"
```

Note `.github/workflows/shell-tool-mcp-ci.yml` defines a fairly standard
CI job for the module (`format`/`build`/`test`).

To test this PR, I pushed this branch to my personal fork of Codex and
ran the CI job there:

https://github.com/bolinfest/codex/actions/runs/19564311320

Admittedly, the graph looks a bit wild now:

<img width="5115" height="2969" alt="Screenshot 2025-11-20 at 11 44
58 PM"
src="https://github.com/user-attachments/assets/cc5ef306-efc1-4ed7-a137-5347e394f393"
/>

But when it finished, I was able to download `codex-shell-tool-mcp-npm`
from the **Artifacts** for the workflow in an empty temp directory,
unzip the `.zip` and then the `.tgz` inside it, followed by `xattr -rc
.` to remove the quarantine bits. Then I ran:

```shell
npx @modelcontextprotocol/inspector node /private/tmp/foobar4/package/bin/mcp-server.js
```

which launched the MCP Inspector and I was able to use it as expected!
This bodes well that this should work once the package is published to
npm:

```shell
npx @modelcontextprotocol/inspector npx @openai/codex-shell-tool-mcp
```

Also, to verify the package contains what I expect:

```shell
/tmp/foobar4/package$ tree
.
├── bin
│   └── mcp-server.js
├── package.json
├── README.md
└── vendor
    ├── aarch64-apple-darwin
    │   ├── bash
    │   │   ├── macos-14
    │   │   │   └── bash
    │   │   └── macos-15
    │   │       └── bash
    │   ├── codex-exec-mcp-server
    │   └── codex-execve-wrapper
    ├── aarch64-unknown-linux-musl
    │   ├── bash
    │   │   ├── centos-9
    │   │   │   └── bash
    │   │   ├── debian-11
    │   │   │   └── bash
    │   │   ├── debian-12
    │   │   │   └── bash
    │   │   ├── ubuntu-20.04
    │   │   │   └── bash
    │   │   ├── ubuntu-22.04
    │   │   │   └── bash
    │   │   └── ubuntu-24.04
    │   │       └── bash
    │   ├── codex-exec-mcp-server
    │   └── codex-execve-wrapper
    ├── x86_64-apple-darwin
    │   ├── bash
    │   │   └── macos-13
    │   │       └── bash
    │   ├── codex-exec-mcp-server
    │   └── codex-execve-wrapper
    └── x86_64-unknown-linux-musl
        ├── bash
        │   ├── centos-9
        │   │   └── bash
        │   ├── debian-11
        │   │   └── bash
        │   ├── debian-12
        │   │   └── bash
        │   ├── ubuntu-20.04
        │   │   └── bash
        │   ├── ubuntu-22.04
        │   │   └── bash
        │   └── ubuntu-24.04
        │       └── bash
        ├── codex-exec-mcp-server
        └── codex-execve-wrapper

26 directories, 26 files
```
2025-11-21 08:16:36 -08:00
..
patches feat: codex-shell-tool-mcp (#7005) 2025-11-21 08:16:36 -08:00
src feat: codex-shell-tool-mcp (#7005) 2025-11-21 08:16:36 -08:00
tests feat: codex-shell-tool-mcp (#7005) 2025-11-21 08:16:36 -08:00
.gitignore feat: codex-shell-tool-mcp (#7005) 2025-11-21 08:16:36 -08:00
jest.config.cjs feat: codex-shell-tool-mcp (#7005) 2025-11-21 08:16:36 -08:00
package.json feat: codex-shell-tool-mcp (#7005) 2025-11-21 08:16:36 -08:00
README.md feat: codex-shell-tool-mcp (#7005) 2025-11-21 08:16:36 -08:00
tsconfig.json feat: codex-shell-tool-mcp (#7005) 2025-11-21 08:16:36 -08:00
tsup.config.ts feat: codex-shell-tool-mcp (#7005) 2025-11-21 08:16:36 -08:00

@openai/codex-shell-tool-mcp

This package wraps the codex-exec-mcp-server binary and its helpers so that the shell MCP can be invoked via npx @openai/codex-shell-tool-mcp. It bundles:

  • codex-exec-mcp-server and codex-execve-wrapper built for macOS (arm64, x64) and Linux (musl arm64, musl x64).
  • A patched Bash that honors BASH_EXEC_WRAPPER, built for multiple glibc baselines (Ubuntu 24.04/22.04/20.04, Debian 12/11, CentOS-like 9) and macOS (15/14/13).
  • A launcher (bin/mcp-server.js) that picks the correct binaries for the current process.platform / process.arch, specifying --execve and --bash for the MCP, as appropriate.

Usage

npx @openai/codex-shell-tool-mcp --help

The launcher selects a Rust target triple based on the host and chooses the closest Bash variant by inspecting /etc/os-release on Linux or the Darwin major version on macOS.

Patched Bash

We carry a small patch to execute_cmd.c (see patches/bash-exec-wrapper.patch) that adds support for BASH_EXEC_WRAPPER. The original commit message is “add support for BASH_EXEC_WRAPPER” and the patch applies cleanly to a8a1c2fac029404d3f42cd39f5a20f24b6e4fe4b from https://github.com/bminor/bash. To rebuild manually:

git clone https://github.com/bminor/bash
git checkout a8a1c2fac029404d3f42cd39f5a20f24b6e4fe4b
git apply /path/to/patches/bash-exec-wrapper.patch
./configure --without-bash-malloc
make -j"$(nproc)"

Release workflow

.github/workflows/shell-tool-mcp.yml builds the Rust binaries, compiles the patched Bash variants, assembles the vendor/ tree, and creates codex-shell-tool-mcp-npm-<version>.tgz for inclusion in the Rust GitHub Release. When the version is a stable or alpha tag, the workflow also publishes the tarball to npm using OIDC. The workflow is invoked from rust-release.yml so the package ships alongside other Codex artifacts.