Clients

Connecting a client

한국어

The server speaks MCP Streamable HTTP with JSON responses at http://127.0.0.1:18765/mcp.

The editor writes both files on startup, so this section is what they contain and how to write them by hand.

For Claude Code, add a .mcp.json file to the project root:

{
  "mcpServers": {
    "unreal": { "type": "http", "url": "http://127.0.0.1:18765/mcp" }
  }
}

If AuthToken is set, add "headers": { "Authorization": "Bearer <token>" } to the server entry.

For Codex, add a .codex/config.toml file to the project root. Codex reads it only in a trusted project, one that ~/.codex/config.toml lists with trust_level = "trusted" after you trust the folder.

[mcp_servers.unreal]
url = "http://127.0.0.1:18765/mcp"
tool_timeout_sec = 600

tool_timeout_sec raises the Codex default of 60 seconds, which compiling, saving and play sessions can exceed. If AuthToken is set, add http_headers = { Authorization = "Bearer <token>" }, or name an environment variable that holds the token with bearer_token_env_var. Start a new Codex session after changing the file.

The server returns short usage instructions from initialize, including the list of skills. Agents should start with editor_get_state.

One port per editor. Every editor that enables the plugin uses the configured port. When two editors run at the same time, the second one cannot bind the port, logs Agent MCP server failed to start, and serves no tools. Give projects that run at the same time different ports, and check the project field of editor_get_state before changing anything.