Custom MCP Servers

Adding a Custom Server

Beyond the built-in catalog, you can connect any MCP-compatible server:

1. Open the agent node config panel
2. Click Add MCP Server → Custom Server
3. Configure:

{
  "name": "My Custom Tools",
  "transport": "streamable-http",
  "url": "https://my-mcp-server.example.com/mcp",
  "authType": "api_key",
  "authCredentialRef": "my_server_key",
  "authHeaderName": "X-API-Key",
  "selectedTools": ["tool_a", "tool_b"],
  "timeout": 30000
}

Configuration Fields

Field	Type	Required	Description
name	string	Yes	Display name
transport	string	Yes	streamable-http or sse
url	string	Yes	Server endpoint URL
authType	string	Yes	none, api_key, or bearer
authCredentialRef	string	For auth	Credential key reference
authHeaderName	string	For api_key	Header name (e.g., X-API-Key)
selectedTools	string[]	Yes	Tool names to enable
timeout	number	No	Per-call timeout in ms (default: 30000)

Tool Discovery

When you add a custom server URL, the flow builder automatically discovers available tools by calling the server’s tool listing endpoint. You can then select which tools to enable.

Requirements

Your MCP server must:

• Implement the MCP protocol (v2025-03-26 or compatible)
• Support streamable HTTP or SSE transport
• Be accessible from the CAVOS Agents runtime (no localhost/private IPs — SSRF protection is enforced)
• Respond within the configured timeout

Tool Schemas

For optimal agent performance, ensure your tools have:

• Clear, descriptive names
• Detailed descriptions explaining when and how to use each tool
• Well-defined JSON Schema for input parameters
• Meaningful error messages on failure