Troubleshooting MCP Integration PatchEntityTool Failure With Limits Enforcement Error In OpenMetadata

August 28, 2025 by StackCamp Team 102 views

MCP Integration PatchEntityTool Failure Troubleshooting Guide

Hey guys! Today, we're diving deep into a tricky issue some of you might have encountered while working with OpenMetadata's MCP (Model Context Protocol) integration. Specifically, we're going to tackle the dreaded PatchEntityTool failure that pops up with a "does not support limits enforcement" error. If you've been scratching your head over this one, you're in the right place. Let's break it down and get you back on track.

Understanding the Issue

When working with OpenMetadata, the MCP integration is a powerful way to manage and update your metadata. However, sometimes, when you try to use the patch_entity tool – especially for updating table metadata like descriptions – you might hit a snag. This issue manifests as an error message stating, "Error executing tool: PatchEntityTool does not support limits enforcement."

Affected Module: MCP Server

This problem primarily affects the MCP Server, which is a crucial component for handling metadata updates within OpenMetadata. The error suggests a limitation within the PatchEntityTool itself, particularly when it comes to enforcing certain limits during patch operations.

Reproducing the Bug

To really understand the issue, let's walk through the steps to reproduce it. This way, you can confirm if you're facing the same problem and follow along with the troubleshooting.

Steps to Reproduce

Set up MCP integration: First, you need to have the MCP integration set up with a service like Claude, as documented in the official OpenMetadata documentation. You can find the details here: OpenMetadata MCP Integration Guide.
Attempt to use openmetadata:patch_entity tool: Next, try to use the openmetadata:patch_entity tool to update a table description. This is where the error typically surfaces.

Observe the error: If you're facing the issue, you should consistently see the following error message:

{
  "statusCode": 500,
  "error": "Error executing tool: PatchEntityTool does not support limits enforcement."
}

Expected Behavior vs. Actual Behavior

It's crucial to understand what should happen versus what's actually happening. Ideally, the patch operation should work smoothly, just like direct API calls. When you use direct API calls, such as the curl command below, updates are applied without any issues:

curl -X PATCH "http://[server]:8585/api/v1/tables/name/[fqn]" \
  -H "Authorization: Bearer [token]" \
  -H "Content-Type: application/json-patch+json" \
  -d '[{"op": "add", "path": "/description", "value": "..."}]'

This command updates a table's description using a PATCH request, which is the expected behavior. However, when using the PatchEntityTool through the MCP integration, this process fails, indicating a discrepancy between the tool's functionality and the direct API.

Diving into the Error Message

Let's dissect the error message a bit more. The error "PatchEntityTool does not support limits enforcement" suggests that the tool is encountering some form of limitation related to how it handles updates. This could be due to how the tool is designed to interact with the OpenMetadata API or how it manages the data being patched.

Possible Causes

Tool limitations: The PatchEntityTool might have inherent limitations in its ability to enforce certain constraints or validations during patch operations. This could be a design choice or an oversight in the tool's implementation.
Integration issues: There might be a problem in how the MCP integration interacts with the PatchEntityTool. The integration might not be correctly passing necessary parameters or handling responses, leading to the error.
Version incompatibility: It's also possible that the issue is due to version incompatibilities between the OpenMetadata version and the MCP integration or the PatchEntityTool itself.

Troubleshooting Steps

Now that we understand the problem and its potential causes, let's get into some troubleshooting steps. These steps should help you identify the root cause and find a solution.

1. Verify OpenMetadata Version

First, ensure you're running a supported version of OpenMetadata. In the reported case, the version is 1.8.0, which should be compatible. However, it's always a good idea to double-check the compatibility matrix in the OpenMetadata documentation.

2. Check MCP Integration Setup

Review your MCP integration setup. Ensure that all the necessary configurations are in place and that the integration is correctly connected to your OpenMetadata instance. Pay close attention to:

Credentials: Verify that the credentials used for the integration have the necessary permissions to perform patch operations.
Configuration parameters: Check if any configuration parameters are misconfigured or missing. Refer to the OpenMetadata documentation for the correct settings.

3. Test Direct API Calls

As mentioned earlier, direct API calls work correctly. This is a good way to isolate the issue to the PatchEntityTool rather than a broader problem with the OpenMetadata API. If direct API calls fail, you might have a more fundamental issue with your OpenMetadata setup.

4. Examine MCP Tool Execution

Try to get more details about how the PatchEntityTool is being executed. Check the logs for any additional error messages or warnings that might provide clues. You might need to increase the logging level to capture more detailed information.

5. Investigate Other MCP Tools

The fact that other MCP tools (like search_metadata and get_entity_details) are working correctly is a valuable piece of information. It suggests that the basic MCP integration is functional, and the issue is specific to the PatchEntityTool. This narrows down the scope of the problem.

6. Review Recent Changes

If the issue started occurring recently, think about any changes that might have been made to your OpenMetadata setup, the MCP integration, or the data being patched. Recent changes are often the culprit behind new issues.

7. Check for Known Issues

Search the OpenMetadata community forums, GitHub issues, and other resources for similar reports. It's possible that this is a known issue with a documented workaround or fix. The OpenMetadata community is quite active, and you might find helpful information there.

8. Analyze MCP Error Spams

Pay attention to the error messages that spam the logs after the failed attempts. The specific error "No handler registered for notification method: notifications/cancelled" suggests an issue with notification handling within the MCP integration. This could be a secondary problem or a symptom of the primary issue.

Solutions and Workarounds

Once you've identified the root cause, you can start working on a solution. Here are some potential solutions and workarounds based on the troubleshooting steps:

1. Use Direct API Calls as a Workaround

If the PatchEntityTool is consistently failing, you can use direct API calls as a temporary workaround. While this might not be ideal in the long run, it allows you to continue updating metadata until a fix is available for the tool.

2. Update OpenMetadata and MCP Integration

If the issue is due to a version incompatibility or a known bug, updating to the latest version of OpenMetadata and the MCP integration might resolve the problem. Check the release notes for any bug fixes related to the PatchEntityTool.

3. Adjust MCP Integration Configuration

Review your MCP integration configuration and make any necessary adjustments. Ensure that all settings are correct and that the integration has the required permissions.

4. Implement Custom Error Handling

If the error spamming is causing instability, consider implementing custom error handling in your MCP integration. This can prevent the errors from overwhelming the system and potentially causing crashes.

5. Contribute to the OpenMetadata Community

If you've identified a bug or a potential improvement for the PatchEntityTool, consider contributing to the OpenMetadata project. You can submit a bug report, propose a feature enhancement, or even contribute code to fix the issue.

Real-World Example and Code Snippets

Let's look at a real-world example to illustrate how you might approach this issue. Suppose you're trying to update the description of a table using the PatchEntityTool, and you encounter the "limits enforcement" error. Here’s how you might troubleshoot:

1. Check the API Call

First, verify that the direct API call works:

curl -X PATCH "http://[server]:8585/api/v1/tables/name/your_table_fqn" \
  -H "Authorization: Bearer your_token" \
  -H "Content-Type: application/json-patch+json" \
  -d '[{"op": "add", "path": "/description", "value": "Updated description"}]'

If this works, you know the issue is specific to the PatchEntityTool.

2. Examine Logs

Next, check the logs for the MCP server to see if there are any additional error messages. You might find something like:

ERROR [2025-08-27 14:00:00,000] [dw-101 - POST /mcp/messages] i.m.o.m.s.PatchEntityTool - PatchEntityTool failed: does not support limits enforcement

This confirms the issue and might provide additional context.

3. Implement a Workaround

As a temporary workaround, you can use the direct API call in your scripts or workflows:

import requests
import json

url = "http://[server]:8585/api/v1/tables/name/your_table_fqn"
headers = {
    "Authorization": "Bearer your_token",
    "Content-Type": "application/json-patch+json"
}
data = '[{"op": "add", "path": "/description", "value": "Updated description"}]'

response = requests.patch(url, headers=headers, data=data)

if response.status_code == 200:
    print("Table description updated successfully")
else:
    print(f"Error updating table description: {response.status_code} - {response.text}")

Conclusion

The "PatchEntityTool does not support limits enforcement" error can be a frustrating issue when working with OpenMetadata's MCP integration. However, by understanding the problem, following a systematic troubleshooting approach, and implementing appropriate solutions or workarounds, you can overcome this hurdle. Remember to leverage the OpenMetadata community and documentation for additional support.

Keep experimenting, keep learning, and you'll become an OpenMetadata pro in no time! If you have any questions or need further assistance, don't hesitate to reach out. Happy metadata managing, guys!