MCP integration

Expose nui to external MCP hosts and inject built-in MCP servers into agent harnesses.

nui integrates with the Model Context Protocol in two directions: as an MCP server for external hosts, and as an MCP client that injects servers into agent harnesses.

nui as an MCP server

Expose nui agents to MCP hosts (Cursor, Claude Desktop, etc.) by adding this to your MCP config:

{
  "mcpServers": {
    "nui": {
      "command": "nui",
      "args": ["mcp"],
      "env": { "NUI_URL": "http://127.0.0.1:8080" }
    }
  }
}

Available tools: list_agents, list_sessions, create_session, run_agent, get_run, get_run_events, stop_run.

The server must be running (nui server) for MCP tools to work.

Built-in MCP servers

nui injects these MCP servers into agent harnesses when configured:

MCP server	Command	Purpose
nui-hitl	nui hitl-mcp	Human-in-the-loop prompts (ask_user, approvals)
nui-viz	nui viz-mcp	Inline chart/visualization rendering in chat
nui-agent	nui agent-mcp	Save ADL agents (save_agent) and update memory (update_memory)
nui-orchestrator	nui orchestrator-mcp	Launcher routing (list_agents, launch_session) for the nui master agent

Remote MCP OAuth

In Settings → MCP servers, remote HTTP MCP servers can authenticate with OAuth. nui exposes /api/mcp-oauth/* for start, callback, status, and disconnect; register the shown redirect URI with your OAuth provider.

Extension MCP servers

Installed extensions can contribute MCP server definitions via contributions.mcpServers in extension.yaml. These are provisioned to harness subprocesses alongside built-in servers.