MCP server rendering wrong filter parameters to API in APIM

Question

MCP server rendering wrong filter parameters to API in APIM

Pamoli Banerjee 40

Hello ,

I have followed blog to expose SAP REST API's as MCP servers that need to be accessed via copilot studio / Microsoft new foundry : https://learn.microsoft.com/en-us/azure/api-management/export-rest-mcp-server. As of now the MCP server is exposing one tool listTasks which has several filter parameters . There is one mandatory argument projectId. When we pass only project ID , we get results:
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But when we send other arguments like type , we get error : ' :
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"text": "{"message":"Parameter value '58870e0c-c579-43d9-9ebb-26373ccdf3a8?type=CALMREQU' is not applicable."}"

Looks like the MCP server is wrongly passing the parameters to the SAP API . How should this be handled?

Pamoli Banerjee 40 Reputation points

2026-01-09T12:21:45.16+00:00

I have added this policy in the MCP server and saved successfully :

After this when I try to connect to the MCP server , I get error "Couldn't run the request: SSE error: Non-200 status code (500)"
Siddhesh Desai 7,400 Reputation points Microsoft External Staff Moderator

2026-01-09T12:49:52.71+00:00

Hi @Pamoli Banerjee

I have asked for some details in the Private conversation, Can you help me with the same?
Pamoli Banerjee 40 Reputation points

2026-01-09T13:47:32.91+00:00

Hello , I have responded in the private message.
Siddhesh Desai 7,400 Reputation points Microsoft External Staff Moderator

2026-01-14T17:09:07.3533333+00:00
Hi @Pamoli Banerjee

the backend team has asked to provide the below details:

I see customer has the following custom policy code added to the MCP API. If this code is removed, does the issue still reproduce?:
  <set-variable name="raw" value="@(context.Request.Body.As<JObject>(preserveContent: true))" />  <set-body>@(((JObject)context.Variables["raw"])["params"]["arguments"].ToString())</set-body>  <set-header name="Content-Type" exists-action="override"> <value>application/json</value> </set-header>
Remove above custom policy and check if the issue still persists?

Please provide exact UTC timestamp of when you reproduced the error "text": "{"message":"Parameter value '58870e0c-c579-43d9-9ebb-26373ccdf3a8?type=CALMREQU' is not applicable."}". If we don't have exact timestamp, please can you repro again (after disabling the custom policy code mentioned in #1).

Please provide the API SPEC of the MCP backend API (I believe it is API with ID sap-cloud-alm-tasks) so we can attempt to reproduce.

Can you please help me with the same details?
Siddhesh Desai 7,400 Reputation points Microsoft External Staff Moderator

2026-01-19T17:22:09.2366667+00:00

Hi @Pamoli Banerjee

Can you please provide the subscription key for the MCP server so we can test directly against it and take some traces on private chat?
Pamoli Banerjee 40 Reputation points

2026-01-20T03:40:34.1566667+00:00

I have provided the same in the chat . Requesting you to please expedite the process, as we are showing MCP server capability in Microsoft to prospective customer. If we can't show this , this might lead to revenue loss.
Siddhesh Desai 7,400 Reputation points Microsoft External Staff Moderator

2026-01-23T08:31:26.8133333+00:00

Hi @Pamoli Banerjee

I have provided an answer with the update from the product team and workaround

Answer accepted by question author

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Your answer

Pamoli Banerjee 40 Reputation points

2026-01-09T12:21:45.16+00:00

I have added this policy in the MCP server and saved successfully :

After this when I try to connect to the MCP server , I get error "Couldn't run the request: SSE error: Non-200 status code (500)"
Siddhesh Desai 7,400 Reputation points Microsoft External Staff Moderator

2026-01-09T12:49:52.71+00:00

Hi @Pamoli Banerjee

I have asked for some details in the Private conversation, Can you help me with the same?
Pamoli Banerjee 40 Reputation points

2026-01-09T13:47:32.91+00:00

Hello , I have responded in the private message.
Siddhesh Desai 7,400 Reputation points Microsoft External Staff Moderator

2026-01-14T17:09:07.3533333+00:00

Hi @Pamoli Banerjee

the backend team has asked to provide the below details:

I see customer has the following custom policy code added to the MCP API. If this code is removed, does the issue still reproduce?:
  <set-variable name="raw" value="@(context.Request.Body.As<JObject>(preserveContent: true))" />  <set-body>@(((JObject)context.Variables["raw"])["params"]["arguments"].ToString())</set-body>  <set-header name="Content-Type" exists-action="override"> <value>application/json</value> </set-header>
Remove above custom policy and check if the issue still persists?

Please provide exact UTC timestamp of when you reproduced the error "text": "{"message":"Parameter value '58870e0c-c579-43d9-9ebb-26373ccdf3a8?type=CALMREQU' is not applicable."}". If we don't have exact timestamp, please can you repro again (after disabling the custom policy code mentioned in #1).

Please provide the API SPEC of the MCP backend API (I believe it is API with ID sap-cloud-alm-tasks) so we can attempt to reproduce.

Can you please help me with the same details?
Siddhesh Desai 7,400 Reputation points Microsoft External Staff Moderator

2026-01-19T17:22:09.2366667+00:00

Hi @Pamoli Banerjee

Can you please provide the subscription key for the MCP server so we can test directly against it and take some traces on private chat?
Pamoli Banerjee 40 Reputation points

2026-01-20T03:40:34.1566667+00:00

I have provided the same in the chat . Requesting you to please expedite the process, as we are showing MCP server capability in Microsoft to prospective customer. If we can't show this , this might lead to revenue loss.
Siddhesh Desai 7,400 Reputation points Microsoft External Staff Moderator

2026-01-23T08:31:26.8133333+00:00

Hi @Pamoli Banerjee

I have provided an answer with the update from the product team and workaround

Answer 1

Hi @Pamoli Banerjee

Thank you for reaching out to Microsoft Q&A.

We received an update from the Product Team.

The product team has confirmed the issue you are facing is a bug and they have opened a work item to fix this bug but the ETA to fix it is months, They have given a workaround that you can use to fix this as an alternative.

What's the bug:

The problem is happening because "projectId" is defined as a URL template parameter in the original Open API, as shown below:

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Due to this, the projectId incorrectly gets considered a "Url Segment" rather than a query string parameter which causes the issue. We will get this issue fixed in a future update (tentative ETA: 6 months).

Workaround:

As a workaround, customer can do the following:

Add a new query string parameter to the "List tasks" operation. The parameter name should be "projectId" and it should be marked as "required". Example below:
1. Remove "?projectId={projectId}" from the Operation URL, as shown below
1. Save the changes After customer makes these changes, query string parameters should correctly get passed to the backend service.

Updated answer:

The product team has confirmed the workaround works perfectly fine and here's the response from the backend team:

The problem that customer ran into is different and has got nothing to do with the workaround implementation. Customer's machine has some connectivity or other problems due to which it cannot even connect to the MCP endpoint https://resourcenamesapcloudalm.azure-api.net/sapcloudalmtasks/mcp

I just tested customer's service using MCP Proxy tool and the workaround is working perfectly fine. Parameters are now being passed correctly. See screenshot below: Request:

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RESPONSE:

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Please verify/investigate why your machine can't connect to the MCP endpoint. Kindly test it on a different machine and check if any connectivity issue is blocking your request.

If the resolution was helpful, kindly take a moment to click on and click on Yes for was this answer helpful. And, if you have any further query do let us know.

Pamoli Banerjee 40 Reputation points

2026-01-23T11:52:48.23+00:00

Hi Siddhesh , the proposed solution dosn't work . Now the MCP server doesn't get connected at all. Please check screenshots in private message.
Siddhesh Desai 7,400 Reputation points Microsoft External Staff Moderator

2026-01-26T10:51:13.2866667+00:00

Hi @Pamoli Banerjee

I have provided your above issue to the product team again. I'll let you know as soon as I receive a response from them.
Siddhesh Desai 7,400 Reputation points Microsoft External Staff Moderator

2026-01-26T17:11:48.88+00:00

Hi @Pamoli Banerjee Please check my Updated answer above.

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MCP server rendering wrong filter parameters to API in APIM

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