This PR introduces an initial `McpClient` that we will use to give Codex
itself programmatic access to foreign MCPs. This does not wire it up in
Codex itself yet, but the new `mcp-client` crate includes a `main.rs`
for basic testing for now.
Manually tested by sending a `tools/list` request to Codex's own MCP
server:
```
codex-rs$ cargo build
codex-rs$ cargo run --bin codex-mcp-client ./target/debug/codex-mcp-server
{
"tools": [
{
"description": "Run a Codex session. Accepts configuration parameters matching the Codex Config struct.",
"inputSchema": {
"properties": {
"approval-policy": {
"description": "Execution approval policy expressed as the kebab-case variant name (`unless-allow-listed`, `auto-edit`, `on-failure`, `never`).",
"enum": [
"auto-edit",
"unless-allow-listed",
"on-failure",
"never"
],
"type": "string"
},
"cwd": {
"description": "Working directory for the session. If relative, it is resolved against the server process's current working directory.",
"type": "string"
},
"disable-response-storage": {
"description": "Disable server-side response storage.",
"type": "boolean"
},
"model": {
"description": "Optional override for the model name (e.g. \"o3\", \"o4-mini\")",
"type": "string"
},
"prompt": {
"description": "The *initial user prompt* to start the Codex conversation.",
"type": "string"
},
"sandbox-permissions": {
"description": "Sandbox permissions using the same string values accepted by the CLI (e.g. \"disk-write-cwd\", \"network-full-access\").",
"items": {
"enum": [
"disk-full-read-access",
"disk-write-cwd",
"disk-write-platform-user-temp-folder",
"disk-write-platform-global-temp-folder",
"disk-full-write-access",
"network-full-access"
],
"type": "string"
},
"type": "array"
}
},
"required": [
"prompt"
],
"type": "object"
},
"name": "codex"
}
]
}
```
This Pull Request addresses an issue where the output of commands
executed in the raw-exec utility was being truncated due to restrictive
limits on the number of lines and bytes collected. The truncation caused
the message [Output truncated: too many lines or bytes] to appear when
processing large outputs, which could hinder the functionality of the
CLI.
Changes Made
Increased the maximum output limits in the
[createTruncatingCollector](https://github.com/openai/codex/pull/575)
utility:
Bytes: Increased from 10 KB to 100 KB.
Lines: Increased from 256 lines to 1024 lines.
Installed the @types/node package to resolve missing type definitions
for [NodeJS](https://github.com/openai/codex/pull/575) and
[Buffer](https://github.com/openai/codex/pull/575).
Verified and fixed any related errors in the
[createTruncatingCollector](https://github.com/openai/codex/pull/575)
implementation.
Issue Solved:
This PR ensures that larger outputs can be processed without truncation,
improving the usability of the CLI for commands that generate extensive
output. https://github.com/openai/codex/issues/509
---------
Co-authored-by: Michael Bolin <bolinfest@gmail.com>
This PR replaces the placeholder `"echo"` tool call in the MCP server
with a `"codex"` tool that calls Codex. Events such as
`ExecApprovalRequest` and `ApplyPatchApprovalRequest` are not handled
properly yet, but I have `approval_policy = "never"` set in my
`~/.codex/config.toml` such that those codepaths are not exercised.
The schema for this MPC tool is defined by a new `CodexToolCallParam`
struct introduced in this PR. It is fairly similar to `ConfigOverrides`,
as the param is used to help create the `Config` used to start the Codex
session, though it also includes the `prompt` used to kick off the
session.
This PR also introduces the use of the third-party `schemars` crate to
generate the JSON schema, which is verified in the
`verify_codex_tool_json_schema()` unit test.
Events that are dispatched during the Codex session are sent back to the
MCP client as MCP notifications. This gives the client a way to monitor
progress as the tool call itself may take minutes to complete depending
on the complexity of the task requested by the user.
In the video below, I launched the server via:
```shell
mcp-server$ RUST_LOG=debug npx @modelcontextprotocol/inspector cargo run --
```
In the video, you can see the flow of:
* requesting the list of tools
* choosing the **codex** tool
* entering a value for **prompt** and then making the tool call
Note that I left the other fields blank because when unspecified, the
values in my `~/.codex/config.toml` were used:
https://github.com/user-attachments/assets/1975058c-b004-43ef-8c8d-800a953b8192
Note that while using the inspector, I did run into
https://github.com/modelcontextprotocol/inspector/issues/293, though the
tip about ensuring I had only one instance of the **MCP Inspector** tab
open in my browser seemed to fix things.
https://github.com/openai/codex/pull/800 kicked off some work to be more
disciplined about honoring the `cwd` param passed in rather than
assuming `std::env::current_dir()` as the `cwd`. As part of this, we
need to ensure `apply_patch` calls honor the appropriate `cwd` as well,
which is significant if the paths in the `apply_patch` arg are not
absolute paths themselves. Failing that:
- The `apply_patch` function call can contain an optional`workdir`
param, so:
- If specified and is an absolute path, it should be used to resolve
relative paths
- If specified and is a relative path, should be resolved against
`Config.cwd` and then any relative paths will be resolved against the
result
- If `workdir` is not specified on the function call, relative paths
should be resolved against `Config.cwd`
Note that we had a similar issue in the TypeScript CLI that was fixed in
https://github.com/openai/codex/pull/556.
As part of the fix, this PR introduces `ApplyPatchAction` so clients can
deal with that instead of the raw `HashMap<PathBuf,
ApplyPatchFileChange>`. This enables us to enforce, by construction,
that all paths contained in the `ApplyPatchAction` are absolute paths.
https://github.com/openai/codex/pull/800 made `cwd` a property of
`Config` and made it so the `cwd` is not necessarily
`std::env::current_dir()`. As such, `is_inside_git_repo()` should check
`Config.cwd` rather than `std::env::current_dir()`.
This PR updates `is_inside_git_repo()` to take `Config` instead of an
arbitrary `PathBuf` to force the check to operate on a `Config` where
`cwd` has been resolved to what the user specified.
