147a940449
This adds initial support for MCP servers in the style of Claude Desktop and Cursor. Note this PR is the bare minimum to get things working end to end: all configured MCP servers are launched every time Codex is run, there is no recovery for MCP servers that crash, etc. (Also, I took some shortcuts to change some fields of `Session` to be `pub(crate)`, which also means there are circular deps between `codex.rs` and `mcp_tool_call.rs`, but I will clean that up in a subsequent PR.) `codex-rs/README.md` is updated as part of this PR to explain how to use this feature. There is a bit of plumbing to route the new settings from `Config` to the business logic in `codex.rs`. The most significant chunks for new code are in `mcp_connection_manager.rs` (which defines the `McpConnectionManager` struct) and `mcp_tool_call.rs`, which is responsible for tool calls. This PR also introduces new `McpToolCallBegin` and `McpToolCallEnd` event types to the protocol, but does not add any handlers for them. (See https://github.com/openai/codex/pull/836 for initial usage.) To test, I added the following to my `~/.codex/config.toml`: ```toml # Local build of https://github.com/hideya/mcp-server-weather-js [mcp_servers.weather] command = "/Users/mbolin/code/mcp-server-weather-js/dist/index.js" args = [] ``` And then I ran the following: ``` codex-rs$ cargo run --bin codex exec 'what is the weather in san francisco' [2025-05-06T22:40:05] Task started: 1 [2025-05-06T22:40:18] Agent message: Here’s the latest National Weather Service forecast for San Francisco (downtown, near 37.77° N, 122.42° W): This Afternoon (Tue): • Sunny, high near 69 °F • West-southwest wind around 12 mph Tonight: • Partly cloudy, low around 52 °F • SW wind 7–10 mph ... ``` Note that Codex itself is not able to make network calls, so it would not normally be able to get live weather information like this. However, the weather MCP is [currently] not run under the Codex sandbox, so it is able to hit `api.weather.gov` and fetch current weather information. --- [//]: # (BEGIN SAPLING FOOTER) Stack created with [Sapling](https://sapling-scm.com). Best reviewed with [ReviewStack](https://reviewstack.dev/openai/codex/pull/829). * #836 * __->__ #829
codex-core
This crate implements the business logic for Codex. It is designed to be used by the various Codex UIs written in Rust.
Though for non-Rust UIs, we are also working to define a protocol for talking to Codex. See:
You can use the proto subcommand using the executable in the cli crate to speak the protocol using newline-delimited-JSON over stdin/stdout.