Version:

This project is part of pgEdge Labs and is under active development. APIs and features may change without notice.

API Reference

HTTP API reference for the MCP Bridge in server mode.

Endpoints

POST /mcp - Send Request

Send a JSON-RPC 2.0 request to the MCP server.

Request

Headers:

Header	Required	Description
`Content-Type`	Yes	Must be `application/json`
`Authorization`	Depends	Required if authentication is enabled
`Mcp-Session-Id`	No	Session ID for stateful connections

Body:

JSON-RPC 2.0 request object.

{
  "jsonrpc": "2.0",
  "method": "string",
  "params": {},
  "id": "string|number"
}

Response

Success (200 OK):

{
  "jsonrpc": "2.0",
  "result": {},
  "id": "string|number"
}

Headers:

Header	Description
`Mcp-Session-Id`	Session ID (on initialize request)

Error Responses:

Status	Description
400	Bad Request - Invalid JSON or JSON-RPC format
401	Unauthorized - Missing or invalid authentication
403	Forbidden - Insufficient permissions
404	Not Found - Session not found
503	Service Unavailable - MCP server not running

Example

curl -X POST http://localhost:8080/mcp \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer my-token" \
  -d '{
    "jsonrpc": "2.0",
    "method": "initialize",
    "params": {
      "protocolVersion": "2024-11-05",
      "clientInfo": {
        "name": "my-client",
        "version": "1.0.0"
      },
      "capabilities": {}
    },
    "id": 1
  }'

GET /mcp - SSE Stream

Subscribe to server-initiated notifications via Server-Sent Events.

Request

Headers:

Header	Required	Description
`Accept`	Yes	Should be `text/event-stream`
`Authorization`	Depends	Required if authentication is enabled
`Mcp-Session-Id`	Recommended	Session ID to filter notifications

Response

Success (200 OK):

Content-Type: text/event-stream

Events are sent in SSE format:

event: message
data: {"jsonrpc":"2.0","method":"notifications/resources/updated","params":{}}

event: message
data: {"jsonrpc":"2.0","method":"notifications/tools/list_changed","params":{}}

Special Events:

Event	Description
`message`	JSON-RPC notification
`close`	Connection being closed

Keep-alive:

The server sends periodic comments to keep the connection alive:

: keepalive

Example

curl -N http://localhost:8080/mcp \
  -H "Accept: text/event-stream" \
  -H "Authorization: Bearer my-token" \
  -H "Mcp-Session-Id: session-123"

DELETE /mcp - Close Session

Close a session and release associated resources.

Request

Headers:

Header	Required	Description
`Authorization`	Depends	Required if authentication is enabled
`Mcp-Session-Id`	Yes	Session ID to close

Response

Success (204 No Content):

No body.

Error Responses:

Status	Description
400	Bad Request - Missing session ID
401	Unauthorized - Invalid authentication
404	Not Found - Session not found

Example

curl -X DELETE http://localhost:8080/mcp \
  -H "Authorization: Bearer my-token" \
  -H "Mcp-Session-Id: session-123"

GET /health - Health Check

Check if the bridge is running and healthy.

Request

No headers required. Authentication is not required for health checks.

Response

Healthy (200 OK):

{
  "status": "healthy"
}

Unhealthy (503 Service Unavailable):

{
  "status": "unhealthy",
  "error": "MCP server not running"
}

Example

curl http://localhost:8080/health

GET /ready - Readiness Check

Check if the bridge is ready to serve requests (MCP subprocess is running).

Request

No headers required. Authentication is not required for readiness checks.

Response

Ready (200 OK):

{
  "status": "ready"
}

Not Ready (503 Service Unavailable):

{
  "status": "not_ready",
  "reason": "mcp_subprocess_not_running"
}

Example

curl http://localhost:8080/ready

OAuth Authorization Server Endpoints

These endpoints are available when oauth_server.enabled: true in the configuration.

GET /.well-known/oauth-authorization-server

Returns OAuth 2.0 Authorization Server Metadata (RFC 8414).

Response (200 OK):

{
  "issuer": "https://mcp.example.com",
  "authorization_endpoint": "https://mcp.example.com/oauth/authorize",
  "token_endpoint": "https://mcp.example.com/oauth/token",
  "jwks_uri": "https://mcp.example.com/oauth/jwks",
  "registration_endpoint": "https://mcp.example.com/oauth/register",
  "scopes_supported": ["mcp:read", "mcp:write"],
  "response_types_supported": ["code"],
  "response_modes_supported": ["query"],
  "grant_types_supported": ["authorization_code", "refresh_token"],
  "token_endpoint_auth_methods_supported": ["none", "client_secret_post"],
  "code_challenge_methods_supported": ["S256"]
}

Example:

curl https://mcp.example.com/.well-known/oauth-authorization-server

GET /oauth/jwks

Returns the JSON Web Key Set for verifying tokens.

Response (200 OK):

{
  "keys": [
    {
      "kty": "RSA",
      "use": "sig",
      "alg": "RS256",
      "kid": "key-1",
      "n": "...",
      "e": "AQAB"
    }
  ]
}

Example:

curl https://mcp.example.com/oauth/jwks

GET /oauth/authorize

Displays the authorization page (login form or IdP redirect).

Query Parameters:

Parameter	Required	Description
`response_type`	Yes	Must be `code`
`client_id`	Yes	Client identifier
`redirect_uri`	Yes	Callback URL
`state`	Recommended	CSRF protection value
`code_challenge`	Yes	PKCE code challenge (S256)
`code_challenge_method`	Yes	Must be `S256`
`scope`	No	Space-separated scopes

Example:

GET /oauth/authorize?response_type=code&client_id=my-client&redirect_uri=https://claude.ai/api/mcp/auth_callback&state=abc123&code_challenge=E9Melhoa...&code_challenge_method=S256

POST /oauth/authorize

Processes the login form submission.

Content-Type: application/x-www-form-urlencoded

Form Fields:

Field	Description
`username`	User's login name
`password`	User's password
`csrf_token`	CSRF token from the form

Response: Redirects to redirect_uri with authorization code.

POST /oauth/token

Exchange authorization code for tokens or refresh tokens.

Content-Type: application/x-www-form-urlencoded

Authorization Code Exchange:

Field	Required	Description
`grant_type`	Yes	`authorization_code`
`code`	Yes	Authorization code
`redirect_uri`	Yes	Must match authorize request
`client_id`	Yes	Client identifier
`code_verifier`	Yes	PKCE code verifier

Refresh Token:

Field	Required	Description
`grant_type`	Yes	`refresh_token`
`refresh_token`	Yes	Refresh token
`client_id`	Yes	Client identifier

Response (200 OK):

{
  "access_token": "eyJhbGciOiJSUzI1NiIs...",
  "token_type": "Bearer",
  "expires_in": 3600,
  "refresh_token": "dGhpcyBpcyBhIHJl...",
  "scope": "mcp:read mcp:write"
}

Error Response (400 Bad Request):

{
  "error": "invalid_grant",
  "error_description": "Authorization code has expired"
}

Example:

curl -X POST https://mcp.example.com/oauth/token \
  -d "grant_type=authorization_code" \
  -d "code=AUTH_CODE" \
  -d "redirect_uri=https://claude.ai/api/mcp/auth_callback" \
  -d "client_id=my-client" \
  -d "code_verifier=VERIFIER"

GET /oauth/callback

Callback endpoint for federated mode. Handles the redirect from the upstream IdP.

Note: This endpoint is only used in federated mode and is not called directly by clients.

Query Parameters:

Parameter	Description
`code`	Authorization code from upstream IdP
`state`	State parameter to correlate with original request
`error`	Error code if authentication failed
`error_description`	Human-readable error description

Response: Redirects to the original client's redirect_uri with either an authorization code or error.

POST /oauth/register

Dynamic client registration (RFC 7591). Only available when allow_dynamic_registration: true.

Content-Type: application/json

Request Body:

{
  "redirect_uris": ["https://example.com/callback"],
  "client_name": "My Application",
  "token_endpoint_auth_method": "none"
}

Response (201 Created):

{
  "client_id": "generated-client-id",
  "client_secret": "generated-secret",
  "redirect_uris": ["https://example.com/callback"],
  "client_name": "My Application",
  "token_endpoint_auth_method": "none"
}

Example:

curl -X POST https://mcp.example.com/oauth/register \
  -H "Content-Type: application/json" \
  -d '{"redirect_uris": ["https://example.com/callback"], "client_name": "My App"}'

Authentication

Bearer Token

Include the token in the Authorization header:

Authorization: Bearer <token>

OAuth

Include the OAuth access token in the Authorization header:

Authorization: Bearer <access_token>

Error Format

Errors are returned as JSON-RPC 2.0 error responses:

{
  "jsonrpc": "2.0",
  "error": {
    "code": -32600,
    "message": "Invalid Request",
    "data": {}
  },
  "id": null
}

Standard Error Codes

Code	Message	Description
-32700	Parse error	Invalid JSON
-32600	Invalid Request	Invalid JSON-RPC request
-32601	Method not found	Unknown method
-32602	Invalid params	Invalid method parameters
-32603	Internal error	Internal server error

Session Management

Sessions enable stateful communication between clients and the MCP server.

Creating a Session

Sessions are created automatically when an initialize request is sent without a Mcp-Session-Id header. The response includes the new session ID:

Mcp-Session-Id: abc123-def456

Using a Session

Include the session ID in subsequent requests:

Mcp-Session-Id: abc123-def456

Session Expiration

Sessions expire after a period of inactivity (configurable via session.timeout). Expired sessions return 404 Not Found.

Rate Limiting

The bridge does not implement rate limiting directly. Use a reverse proxy (nginx, HAProxy, etc.) for rate limiting in production.

CORS

When CORS is enabled, the server handles preflight requests and includes appropriate CORS headers:

Access-Control-Allow-Origin: https://app.example.com
Access-Control-Allow-Methods: GET, POST, DELETE, OPTIONS
Access-Control-Allow-Headers: Authorization, Content-Type, Mcp-Session-Id
Access-Control-Expose-Headers: Mcp-Session-Id
Access-Control-Allow-Credentials: true
Access-Control-Max-Age: 3600