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" />
codex-core
This crate implements the business logic for Codex. It is designed to be used by the various Codex UIs written in Rust.
Dependencies
Note that codex-core makes some assumptions about certain helper utilities being available in the environment. Currently, this
macOS
Expects /usr/bin/sandbox-exec to be present.
Linux
Expects the binary containing codex-core to run the equivalent of codex debug landlock when arg0 is codex-linux-sandbox. See the codex-arg0 crate for details.
All Platforms
Expects the binary containing codex-core to simulate the virtual apply_patch CLI when arg1 is --codex-run-as-apply-patch. See the codex-arg0 crate for details.