AzureDevops UI is broken when reporting code comments with repo_create_pull_request_thread

[dlecan]

For a couple of weeks, Claude generates PR code comments which breaks ADO UI, with the following error:

An unexpected error has occurred within this region of the page.
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TypeError: can't access property "line", s is undefined
    getIntegrationContext https://cdn.vsassets.io/ext/ms.vss-code-web/pr-details-content/ms.vss-co
de-web.pr-details-content.es6.4rpdS9.min.js:1
    addThreadToWidget https://cdn.vsassets.io/ext/ms.vss-code-web/discussion-diff-integration-cont
ent/ms.vss-code-web.discussion-diff-integration-content.es6.XZ7gQJ.min.js:1
    initialize https://cdn.vsassets.io/ext/ms.vss-code-web/discussion-diff-integration-content/ms.
vss-code-web.discussion-diff-integration-content.es6.XZ7gQJ.min.js:1
    i https://cdn.vsassets.io/ext/ms.vss-code-web/discussion-diff-integration-content/ms.vss-code-
web.discussion-diff-integration-content.es6.XZ7gQJ.min.js:1
    getMonacoIntegration https://cdn.vsassets.io/ext/ms.vss-code-web/pr-details-content/ms.vss-cod
e-web.pr-details-content.es6.4rpdS9.min.js:1 

Here is a sample of the MCP call:

azureDevOps - repo_create_pull_request_thread (MCP)(repositoryId:
                                                     "REDACTED",
                                                     pullRequestId: REDACTED, content: "REDACTED", filePath: "/path/to/file",
                                                     rightFileStartLine: 1, rightFileStartOffset: 1)
  ⎿ {                                                                                            
      "id": 74961,
      "publishedDate": "2025-12-12T09:58:06.877Z",
      "lastUpdatedDate": "2025-12-12T09:58:06.877Z",
      "status": 1,
      "comments": [
        {
          "id": 1,
          "author": {
            "displayName": "REDACTED",
            "uniqueName": "REDACTED"
          },
          "content": "REDACTED",
          "publishedDate": "2025-12-12T09:58:06.877Z",
          "lastUpdatedDate": "2025-12-12T09:58:06.877Z",
          "lastContentUpdatedDate": "2025-12-12T09:58:06.877Z"
        }
      ],
      "threadContext": {
        "filePath": "/path/to/file",
        "rightFileStart": {
          "line": 1,
          "offset": 1
        }
      }
    }

$ npx @azure-devops/mcp --version
2.2.2

Is it a bug? Which instruction could I send to Claude to correctly use this tool?

[danhellem]

Do you run into this same issue using VS Code? Is it specific to Claude (which it should not be, that would be weird).

[dlecan]

No, I don't use VSCode/Copilot.
After a debugging session with Claude, I found the MCP server should enforce rightFileEnd when rightFileStart is provided, or the Azure DevOps API should reject requests missing rightFileEnd instead of accepting them and corrupting the UI state.

I permanently asked Claude to follow this recommendation to check if this fixes the issue.
Follow-up in the next days.

[danhellem]

I am guessing the issue is becuase you called

 "rightFileStart": {
          "line": 1,
          "offset": 1
        }

but you also need

 "rightFileEnd": {
          "line": 1,
          "offset": 10
        }

I will fix the tool to make sure that filestart and fileEnd both have values in order for you save

[danhellem]

See fixes in #802

Closing this issue and waiting for merge