🏇 Avenor

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Codex plugin ​

Manually registering Avenor's MCP server gives Codex the tools, but it leaves Codex to work out how to use them. The Avenor plugin packages the existing Go MCP server with orchestration instructions and Codex-facing metadata.

This is not another Avenor implementation. The plugin starts avenor mcp, so the same binary and MCP lifecycle described in the MCP guide remain underneath it.

Prerequisites ​

  • Install Avenor and make sure avenor is on your PATH.
  • Install a Codex CLI version that supports plugins.

You can confirm that Codex will be able to find the binary before installing the plugin:

bash
avenor --help

Setup ​

  1. Register Avenor's marketplace from GitHub:
bash
codex plugin marketplace add sdougbrown/avenor
  1. Install Avenor from the registered marketplace:
bash
codex plugin add avenor@avenor
  1. Start a new Codex task. Plugin MCP servers and skills are loaded when the task starts, so an already-open task will not pick up the integration.

For GitHub and repository-root installs, Codex and Claude Code both consume .claude-plugin/marketplace.json. That manifest points to marketplace/plugins/avenor, where Codex loads .codex-plugin/plugin.json. The separate marketplace/.agents/plugins/marketplace.json supports registering only the marketplace/ subdirectory.

Installing from a local checkout or branch ​

The GitHub source above is the normal installation path. To test local plugin changes, register the repository root instead. Replace /absolute/path/to/avenor with the checkout's absolute path:

bash
codex plugin marketplace add /absolute/path/to/avenor

To test a Git branch without cloning it, pin that ref when registering the GitHub source:

bash
codex plugin marketplace add sdougbrown/avenor --ref feature/my-plugin-change

These are alternative marketplace sources; use one registration method, then run codex plugin add avenor@avenor as usual.

Verification ​

List the installed plugins:

bash
codex plugin list

Confirm that Avenor appears as an installed plugin from the avenor marketplace. In a new Codex task, asking Codex to delegate explicitly through Avenor should make the MCP tools (spawn, status, message, peers, and so on) available. Avenor delegation remains opt-in; the bundled skill does not dispatch ordinary work without an explicit request.

Troubleshooting ​

Codex cannot start the MCP server ​

The plugin runs avenor mcp by command name. Make sure the directory containing the Avenor binary is on the PATH inherited by Codex, then start a new task.

Codex cannot find the marketplace ​

Check whether the marketplace was registered:

bash
codex plugin marketplace list

If avenor is missing, retry with the exact owner and repository name:

bash
codex plugin marketplace add sdougbrown/avenor

This step needs network access to GitHub. If GitHub registration still fails and you have a local checkout, register its absolute repository-root path instead:

bash
codex plugin marketplace add /absolute/path/to/avenor

The plugin is installed but its tools are missing ​

Start a new Codex task after installation. MCP tools and the orchestration skill are not added retroactively to an existing task.

See also ​

  • MCP server covers the underlying server, transports, tools, and registry scope.
  • Claude Code plugin covers the equivalent integration for Claude Code.
  • CLI reference covers Avenor commands outside the Codex integration.

Peer layer ​

The plugin also ships hooks/codex.json, which makes an interactive Codex session a broker peer of an avenor stable supervisor: the session registers its own run, message and peers act as that run, and inbound peer messages arrive as Codex-queued turns. Set AVENOR_BROKER_URL in the session's environment (and optionally AVENOR_LABEL for its display name), then approve the plugin's hooks when Codex asks. The full drive, proof state and limits are in skills/verify-avenor/features/codex-peers.md.