Copilot Studio Integration – HTTP 404 with MCP Server

[lakal96]

Hi team,

We're working on a PoC to integrate Copilot Studio custom agent with aks-mcp and wanted to get your input on an issue we're facing.

Our current architecture:

Copilot Studio custom agent → custom connector (Logic App) → aks-mcp v0.0.2 (running in an internal Azure Container Instance)

We've successfully deployed the setup, but when the Logic App connector tries to send requests to the MCP server over HTTP, we consistently get a 404 "Page Not Found" error.

Based on the documentation, we believe the MCP server expects requests at the /mcp endpoint (not /) and that it supports JSON-RPC methods such as "initialize", "tools/list", and "tools/call".

We’d really appreciate your guidance on the following:

Is there a correct way to structure HTTP requests for MCP to avoid the 404 error (e.g., endpoint path, headers, required payload)?

Alternatively, is there a recommended approach to connect MCP to Copilot Studio using stdio directly, considering MCP’s default transport is stdio?

Happy to share our current connector configuration or setup details if helpful.
Looking forward to any advice or suggestions you might have.

Thanks in advance!
— Lakal

[sojournerdev]

Hi Lakal,

For your setup, make sure you initialize with the MCP server before making any other calls. MCP over HTTP requires the client to first send an initialize request to the /mcp endpoint.

When the server accepts the request, it will return an Mcp-Session-Id in the response headers. You must include this same Mcp-Session-Id in every subsequent request (tools/list, tools/call, etc.) so the MCP server can associate calls with your session.

Example flow:

Step 1 – Initialize

Step 2 – List tools
Use the Mcp-Session-Id returned above.

If both steps succeed, the MCP server is ready and your connector should work as long as it follows the same handshake sequence.

[feiskyer]

Good sugestions, filed #169 to improve the error handling and add guidances for 404 endpoints.

[feiskyer]

The PR has been merged and would be part of next release (v0.0.7).