Integrations
Custom MCP
Connect Castrel to any MCP-compliant external server and automatically discover and load its exposed tools.
Overview
- Connector name:
custom_mcp - Protocol: Model Context Protocol (MCP)
- Transport types: Streamable HTTP / SSE
- Official docs: MCP Protocol Documentation
Configuration
To use a Custom MCP server, create a Connector with the following fields:
| Field | Required | Description |
|---|---|---|
instance_name | Yes | Display name for this connector instance |
runtime_mode | Yes | Runtime mode: direct (backend direct connection) or bridge (via Castrel Proxy) |
base_url | No | MCP endpoint URL (required when runtime_mode=direct) |
transport_type | No | Transport type: streamable_http (default) or sse |
bridge_client_id | No | Paired Castrel Proxy node client_id (required when runtime_mode=bridge) |
bridge_server_name | No | MCP server name on the Castrel Proxy side (recommended when runtime_mode=bridge) |
headers | No | Custom HTTP headers appended to requests (for authentication) |
Available Tools
After connecting, the Custom MCP connector automatically discovers all tools exposed by the server — no manual configuration needed.
- Automatic tool discovery: Lists all tools provided by the MCP server after connection
- Dynamic tool invocation: AI can directly call any tool exposed by the server
- Castrel Proxy mode: Access internal-network MCP services via Castrel Proxy without public exposure