Host features

Codex MCP server

The Codex plugin docs describe bundled MCP servers and plugin-scoped policy under plugins.<plugin>.mcp_servers.<server>, with a remote HTTP server as the example. They do not cover local stdio paths. A live run with codex-cli 0.159.0 on 2026-10-05, with the plugin installed from this repository into a temporary CODEX_HOME, showed:

• ${CLAUDE_PLUGIN_ROOT} and ${PLUGIN_ROOT} stay literal in MCP args, so the server does not start.
• "cwd": "." resolves to the plugin root. With "args": ["./tools/mcp-server.mjs"], all 8 tools load.
• The server gets no project directory: no environment variable, no MCP roots, and no cwd in the call _meta. Its working directory is the plugin root.

So the Codex manifest points mcpServers at .codex-mcp.json, which uses the relative path and cwd. In Codex, each project tool needs the cwd argument. Without it, the server refuses the call, since a project edit would land in the plugin cache.

The concise-config and concise-tune skills call the CLI, so they work without the server. To register the server by hand instead:

codex mcp add concise -- node /path/to/plugins/concise/tools/mcp-server.mjs