ServiceNow MCP Client not working

YashKumarV
Tera Contributor

Wednesday

Hello Everyone.

I wanted to check if there is any update or official guidance on MCP Server compatibility with ServiceNow at the moment.

Issue I’m facing:

  • I have a custom MCP Server locally hosted

  • When I add it in ServiceNow AI Agent Studio and try to use it as a tool, I get the error:
    “Unable to fetch tools for the MCP server”

  • The same MCP server works correctly when tested using:

    • MCP Inspector

    • Postman (as an MCP client)

Below are the record data from the MCP Execution Logs (sn_mcp_execution_logs) table:
Request = {"protocolVersion":"2025-06-18","clientInfo":{"version":"1.0.0","name":"Servicenow"},"capabilities":{}}

Error Message = Flow Action execution failed: Method failed: (/mcp/) with code: 406

Method = initialize

 

The error I got was related to the Content-Type headers where it shows that:

"error": {
        "code": -32600,
        "message": "Not Acceptable: Client must accept both application/json and text/event-stream"
    }
 
Additional Errors Observed in ServiceNow System Logs:
Screenshot 2026-01-05 214827.png

 

Additional observation:

  • I was able to successfully add and use the open-source Microsoft Learning MCP Server in ServiceNow without any issues, which suggests the ServiceNow MCP client itself is functional.

So I wanted to understand:

  • Is ServiceNow MCP client currently limited to only application/json responses?

  • Is it possible to change the headers in ServiceNow to make it compatible with my custom MCP Server?

  • Are there any known limitations or required MCP server patterns (tool exposure, transport, headers, etc.) that custom servers must strictly follow?

  • Is there any update or planned fix to improve compatibility with custom/local MCP servers?

Any clarification or updates on this would be really helpful. Thanks!

@warren_chan

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5 REPLIES 5

NikitaAgarwal
Mega Guru
In response to warren_chan

yesterday

Hi @warren_chan 

 

To confirm, we are currently using the latest version of the MCP Client plugin (v1.1.2).


In our case, we do not own or control the MCP server, so unfortunately, we are unable to modify the header requirements on the server side.

 

Could you please let us know if there is a way to update the headers in ServiceNow to include both application/json and text/event-stream? If so, we can proceed with this approach for now. Otherwise, we would need to build our own MCP client in ServiceNow, which is not the preferred approach.

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