Configuration

Environment variables, authentication modes, server settings, and LLM provider setup.

Environment Variables

Copy .env.example to .env:

BACKEND_PORT=5002
FRONTEND_PORT=5173
# MCP_LENS_API_KEY=your-secret-api-key
# DATABASE_URL=sqlite+aiosqlite:///mcp_secrets.db
# PERSIST_OAUTH_TOKENS=true

Authentication Modes

Mode Description Config
None No authentication auth: false
Bearer token Static JWT/token auth_mode: bearer_token
API key Static key auth_mode: api_key
OAuth OAuth 2.0 authorization code auth_mode: oauth
DCR Dynamic Client Registration + OAuth auth_mode: dcr

Bearer tokens and API keys are encrypted at rest (Fernet/AES-128-CBC). Set MCP_LENS_ENCRYPTION_KEY in .env.

Server Config Fields

Field Type Default Description
url string required MCP server endpoint URL
transport string streamable_http Transport protocol
auth bool false Whether auth is required
auth_mode string null Auth type
ssl_verify bool true Verify SSL certificates
timeout int 30 Connection timeout (seconds)
description string "" Human-readable description
oauth object null OAuth config
api_key_config object null API key config

LLM Configuration

Create llm.json (copy llm.json.example):

{
  "default": "gemini-flash",
  "configs": {
    "gemini-flash": {
      "provider": "vertexai",
      "model": "gemini-2.5-flash",
      "credentials_env": "GOOGLE_APPLICATION_CREDENTIALS"
    },
    "claude": {
      "provider": "anthropic",
      "model": "claude-sonnet-4-20250514",
      "api_key_env": "ANTHROPIC_API_KEY"
    }
  }
}

Environment Variable Convention

Fields ending in _env reference environment variable names, not literal values. For example, "api_key_env": "ANTHROPIC_API_KEY" means MCP Lens reads the actual key from the ANTHROPIC_API_KEY environment variable at runtime.

Vertex AI

For Vertex AI providers (vertexai, anthropic-vertex), project and location are optional. If omitted, they are inferred from the service account credentials or application default credentials.

Supported Providers

openai anthropic vertexai anthropic-vertex