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atmos mcp start

Use this command to start the Atmos Model Context Protocol (MCP) server. The MCP server exposes Atmos AI tools through the MCP open standard, enabling any compatible AI client — Claude Desktop, Claude Code, VS Code, Cursor, and many others — to connect to your infrastructure tools.

Experimental

Configure MCP

Learn how to configure MCP server and AI tool settings in your atmos.yaml.

atmos mcp start --help

Prerequisites​

The MCP server must be explicitly enabled in atmos.yaml:

mcp:
  enabled: true
ai:
  enabled: true
  tools:
    enabled: true

The MCP server is disabled by default. Enabling AI features alone (ai.enabled: true) does not enable MCP.

Description​

The atmos mcp start command starts the Atmos MCP server, enabling AI clients to query your infrastructure using Atmos tools.

The server supports two transport protocols:

  • stdio (default) — Standard input/output for desktop apps like Claude Desktop, VS Code, and Cursor
  • http — HTTP with Server-Sent Events (SSE) for remote access, shared servers, and CI/CD

Usage​

atmos mcp start [flags]

Flags​

--transport
Transport type: stdio (default) or http
--host
Host to bind HTTP server (HTTP transport only). Default: localhost
--port
Port to bind HTTP server (HTTP transport only). Default: 8080

Examples​

# Start MCP server with stdio transport (default, for desktop clients)
atmos mcp start

# Start MCP server with HTTP transport
atmos mcp start --transport http

# Start HTTP server on custom host and port
atmos mcp start --transport http --host 127.0.0.1 --port 3000

Transport Modes​

How it works
stdio (default): Client spawns Atmos as a subprocess; communication over stdin/stdout. HTTP: Atmos listens on an HTTP port with SSE.
Best for
stdio: Desktop apps, local development. HTTP: Remote access, shared servers, CI/CD.
Multiple clients
stdio: No (1:1 with client). HTTP: Yes.
Network exposure
stdio: None. HTTP: Requires security measures.

HTTP Endpoints​

When running with --transport http, the server exposes:

GET /sse
Server-Sent Events stream for client communication.
POST /message
JSON-RPC 2.0 message endpoint.
GET /health
Returns {"status":"healthy","clients":N}. Use for monitoring and liveness probes.
HTTP Transport

When using --transport http, the server has no built-in authentication. Always add firewall rules, VPN, or a reverse proxy before exposing it on a network. The default stdio transport has no network exposure.