Gemini CLI

Gemini CLI supports Streamable HTTP MCP servers through gemini mcp add or settings.json.

Add The Server

For a Dagu server without authentication:

gemini mcp add --transport http dagu "$DAGU_MCP_URL"

For a Dagu server using builtin authentication:

gemini mcp add --transport http dagu "$DAGU_MCP_URL" \
  --header "Authorization: Bearer $DAGU_MCP_API_KEY"

The command shape is gemini mcp add [options] <name> <commandOrUrl> [args...], and --transport defaults to stdio, so --transport http is required for Dagu.

Configuration File

Gemini CLI stores servers in ~/.gemini/settings.json for all projects, or .gemini/settings.json for one project:

{
  "mcpServers": {
    "dagu": {
      "httpUrl": "http://localhost:8080/mcp",
      "headers": {
        "Authorization": "Bearer ${DAGU_MCP_API_KEY}"
      }
    }
  }
}

Use httpUrl. Gemini CLI treats httpUrl as Streamable HTTP and url as an SSE endpoint, and Dagu only serves Streamable HTTP, so an entry written with url fails to connect.

Values can reference environment variables with $VAR_NAME or ${VAR_NAME}, so a project-level settings file can be committed while the key stays in each user's environment.

Verify

gemini mcp list

Inside a session, /mcp shows the server list, connection status, and discovered tools.

Reference: Gemini CLI MCP documentation.