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mcp-agent cloud supports multiple authentication modes so you can choose the right balance between security and accessibility. This page introduces the architecture and flows; the detailed configuration lives in the sub-pages.

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Components

ComponentRole
Authorization serverIssues API keys today; OAuth 2.1 support (authorization code flow) is in development. Hosted in LastMile’s control plane.
Resource server (your deployment)Exposes MCP endpoints (call_tool, read_resource, etc.) and validates tokens. Powered by FastMCP + MCPApp.
ClientsMCP clients (Claude Desktop, Cursor, ChatGPT Apps), custom code (Python, cURL), or other MCP servers calling downstream resources.
Secrets serviceStores deployment/user secrets, eliminating the need to embed credentials in clients.
Agents exposed as MCP servers, sitting between MCP clients and downstream MCP servers

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Modes at a glance

ModeUse caseHowDocs
Bearer token (default)Internal deployments, quick sharing within a teammcp-agent login → provides MCP_API_KEY. Clients send Authorization: Bearer.Deployment auth →
UnauthenticatedPublic endpoints, ChatGPT AppsDeploy with mcp-agent deploy ... --no-auth.Deployment auth →
OAuth 2.1 (Upcoming)Enterprise SSO, fine-grained scopesFollows MCP OAuth spec (RFC 9728 + RFC 8414).(Coming soon)
External MCP authYour agent needs to authenticate to downstream MCP serversConfigure mcp_agent.config.yaml -> mcp.servers.<name>.auth for API keys or OAuth client credentials.External MCP auth →

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Current flow (Bearer tokens)

  1. Developer or user runs mcp-agent login.
  2. Browser-based auth returns an API key (lm_mcp_api_*), stored locally.
  3. CLI and MCP clients use the key in the Authorization: Bearer header.
  4. Deployment validates the token before executing tools/workflows.

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Upcoming OAuth architecture

The forthcoming OAuth implementation follows the MCP Authorization specification:
  • /.well-known/oauth-authorization-server metadata endpoint (RFC 8414).
  • Authorization endpoint (/oauth2/authorize) supporting Google, GitHub, and custom IdPs.
  • Token endpoint (/oauth2/token) returning access + refresh tokens.
  • Resource server metadata (/.well-known/oauth-protected-resource) for deployments advertising supported methods (bearer_methods_supported, scopes).
  • Token introspection and JWKS endpoints for JWT validation.
We aim to make the default configuration zero-touch for mcp-agent cloud deployments while still allowing you to point at other OAuth providers if you self-host.

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Choosing an authentication mode

  • Internal tools or staging → keep bearer tokens (fastest path).
  • Publishing to ChatGPT Apps → deploy with --no-auth, optionally combine with rate limiting in code.
  • Customer-facing apps → use bearer tokens initially, migrate to OAuth when available to integrate with existing identity providers.
  • Agents calling other MCP servers → configure outbound auth in mcp_agent.config.yaml. This is independent of how end-users authenticate to your deployment.
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