This is how an external MCP client — Claude, an IDE, or any Model Context Protocol‑compatible app — talks to a server you built in this module, plus the errors you may hit while wiring one up.
Finding Your Server's URL
Click Manage API in the server header. The server's API group lists its two endpoints with their full URLs:
Endpoint | Method | Path suffix |
|---|---|---|
SSE | GET |
|
JSON-RPC | POST |
|
Point an SSE-based MCP client at the mcp/sse URL.
Giving the Client Credentials
The server's endpoints are protected like any other API on the API Platform, so the MCP client must authenticate. A request without valid credentials is refused with 401 Unauthorized.
In API Manager › Clients, click New Client (or open an existing client).
Under the client's Access Profiles, add an access profile, choose its authentication method, and include this server's API group.
Give the MCP client the credential the access profile generates.
MCP clients that support OAuth can also discover the server's authorization details from its URL and sign in on their own. See Authentication Methods and Clients & Access Profiles.
How a Client Session Works
The server uses the MCP SSE transport. The client opens the mcp/sse endpoint, which creates a session and tells the client where to post messages; the client then sends JSON-RPC requests to mcp/messages with its sessionId, starting with the standard MCP handshake (initialize, then the initialized notification) before it can list and call anything.
The server supports listing tools, calling tools, listing prompts, fetching a prompt, ping, and — if enabled in Settings — list-changed notifications for tools and prompts.
Why Does My Client Get "MCP Server not found"?
What's happening: requests return a not-found error naming the MCP Server.
Why: the server is switched Inactive (all requests are rejected while it's off) — new servers start Inactive.
Fix: open the server and flip the header toggle to Active.
Other Errors a Client Can Hit
Error | Cause |
|---|---|
401 Unauthorized | The client sent missing or invalid credentials, or its access profile is switched off. Give the client a valid credential (see Giving the Client Credentials). |
403 Forbidden | The client's access profile doesn't include this server's API group. Add the API group to the access profile. |
"SessionId is absent" | The message was posted without a |
"No Session found for sessionId: …" or "Session expired for sessionId: …" | The session is unknown or has lapsed; reconnect to the SSE endpoint. |
"Session is not initialized. Please send initialize request" | The client skipped the MCP |
"Invalid methodName: …" | The client called a method this server doesn't support. |
Is This the Same as the "MCP Servers" Connector?
No — they're opposites. This module hosts MCP servers that outside clients call into. The MCP Servers connector (in integrations, with its own connection types such as token, basic, OAuth, or no auth) is for the reverse: calling external MCP servers from your workflows and agents.