Sentry MCP gets 'str' object has no attribute 'message' when trying to fetch issue

[rsslldnphy]

Describe the bug
When trying to fetch an issue using the Sentry mcp server, Claude gets a Python error:

'str' object has no attribute 'message'

To Reproduce
Steps to reproduce the behavior:

1. set up sentry MCP server in claude using the following config:

"sentry": {
      "command": "/Users/REDACTED/.local/bin/uvx",
      "args": [
        "mcp-server-sentry",
        "--auth-token",
        "REDACTED"
      ]
    }

2. Ask claude to fetch an issue

Expected behavior
It should fetch the issue details

Logs

nothing obviously useful in the logs:

2025-02-27T09:08:41.113Z [sentry] [info] Message from server: {"jsonrpc":"2.0","id":274,"result":{"prompts":[{"name":"sentry-issue","description":"Retrieve a Sentry issue by ID or URL","arguments":[{"name":"issue_id_or_url","description":"Sentry issue ID or URL","required":true}]}]}}

[rsslldnphy]

Further info on this: it happens in one Sentry account I have set up but not in another. Can't see any obvious way in which the two accounts could be set up differently that could cause this.