## Stack - Base: #27184 - This PR is the second vertical and should be reviewed against `jif/external-plugins-1`, not `main`. ## Why CCA is moving toward a split runtime where the orchestrator may have no filesystem or executor, but it still needs to activate remotely hosted plugin components. HTTP MCP servers are the simplest complete example: they need configuration and host authentication, but they do not need an executor process. The Apps MCP endpoint is currently synthesized by a special-purpose loader inside the MCP runtime. That works locally, but it leaves hosted MCP activation outside the extension model being established in #27184. It also makes the Apps path a poor foundation for plugins whose skills, MCP servers, connectors, and hooks may come from different sources or execute in different places. This PR moves that one behavior behind an extension-owned contribution while preserving the existing local fallback. It deliberately does not introduce a generic plugin activation framework. ## What changed ### MCP extension contribution `codex-extension-api` gains an ordered `McpServerContributor` contract. A contributor returns typed `Set` or `Remove` overlays for MCP server configuration; later contributors win for the names they own. The contract stays at the existing MCP configuration boundary. Extensions do not create a second connection manager or transport abstraction. ### Hosted Apps MCP extension A new `codex-mcp-extension` contributes the reserved `codex_apps` server from the existing Apps feature, ChatGPT base URL, path override, and product SKU configuration. When `apps_mcp_path_override` is enabled for `https://chatgpt.com`, the resulting streamable HTTP endpoint is `https://chatgpt.com/backend-api/ps/mcp`. The existing ChatGPT-auth gate remains authoritative, so this server can run in an orchestrator-only process without being exposed for API-key sessions. ### One resolved runtime view `McpManager` now distinguishes three views: - **configured:** config- and plugin-backed servers before extension overlays; - **runtime:** configured servers plus host-installed extension contributions; - **effective:** runtime servers after auth gating and compatibility built-ins. App-server installs the hosted MCP extension and uses the runtime view for thread startup, refresh, status, threadless resource reads, connector discovery, and MCP OAuth lookup. This keeps `mcpServer/oauth/login` consistent with the servers exposed by the other MCP APIs. The hosted Apps server itself continues to use existing ChatGPT host authentication rather than MCP OAuth. ## Compatibility Hosts that do not install the MCP extension retain the existing Apps MCP synthesis path. This preserves current local-only, CLI, and standalone-host behavior while app-server exercises the extension path. Disabling Apps removes the reserved `codex_apps` entry, and losing ChatGPT auth removes it from the effective runtime view. Executor availability is not consulted for this HTTP transport. ## Follow-ups The next vertical will resolve a manifest-declared stdio MCP server from an executor-selected plugin root and execute it in the environment that owns that root. Later verticals can add backend-owned skills, connector metadata, hooks, durable selection semantics, and incremental local convergence without changing the component-specific runtime boundaries introduced here. ## Verification Focused coverage was added for: - contributing the hosted Apps MCP at `/backend-api/ps/mcp` without an executor; - requiring ChatGPT auth in the effective runtime view; - removing a reserved configured Apps server when the Apps feature is disabled. `cargo check -p codex-app-server -p codex-mcp-extension -p codex-extension-api -p codex-mcp` passed. Tests and Clippy were not run locally under the current development instruction; CI provides the full validation pass.
Codex CLI is a coding agent from OpenAI that runs locally on your computer.
If you want Codex in your code editor (VS Code, Cursor, Windsurf), install in your IDE.
If you want the desktop app experience, run
codex app or visit the Codex App page.
If you are looking for the cloud-based agent from OpenAI, Codex Web, go to chatgpt.com/codex.
Quickstart
Installing and running Codex CLI
Run the following on Mac or Linux to install Codex CLI:
curl -fsSL https://chatgpt.com/codex/install.sh | sh
Run the following on Windows to install Codex CLI:
powershell -ExecutionPolicy ByPass -c "irm https://chatgpt.com/codex/install.ps1 | iex"
Codex CLI can also be installed via the following package managers:
# Install using npm
npm install -g @openai/codex
# Install using Homebrew
brew install --cask codex
Then simply run codex to get started.
You can also go to the latest GitHub Release and download the appropriate binary for your platform.
Each GitHub Release contains many executables, but in practice, you likely want one of these:
- macOS
- Apple Silicon/arm64:
codex-aarch64-apple-darwin.tar.gz - x86_64 (older Mac hardware):
codex-x86_64-apple-darwin.tar.gz
- Apple Silicon/arm64:
- Linux
- x86_64:
codex-x86_64-unknown-linux-musl.tar.gz - arm64:
codex-aarch64-unknown-linux-musl.tar.gz
- x86_64:
Each archive contains a single entry with the platform baked into the name (e.g., codex-x86_64-unknown-linux-musl), so you likely want to rename it to codex after extracting it.
Using Codex with your ChatGPT plan
Run codex and select Sign in with ChatGPT. We recommend signing into your ChatGPT account to use Codex as part of your Plus, Pro, Business, Edu, or Enterprise plan. Learn more about what's included in your ChatGPT plan.
You can also use Codex with an API key, but this requires additional setup.
Docs
This repository is licensed under the Apache-2.0 License.
