Bug: create_update mutation fails with 'Unknown type UpdateMention'

[Koobah]

Bug Report: create_update mutation fails with "Unknown type UpdateMention"

Summary

The mcp__monday-api-mcp__create_update tool fails with GraphQL schema errors indicating that UpdateMention type and mentions_list argument don't exist in Monday.com's current API.

Environment

• Package: @mondaydotcomorg/monday-api-mcp
• MCP Server: Started via npx -y @mondaydotcomorg/monday-api-mcp --token $MONDAY_API_KEY
• Client: Claude Code with MCP integration
• Date Observed: 2025-11-19

Error Details

Full Error Response

{
  "response": {
    "errors": [
      {
        "message": "Unknown type \"UpdateMention\". Did you mean \"UpdatePin\"?",
        "locations": [{"line": 2, "column": 71}]
      },
      {
        "message": "Unknown argument \"mentions_list\" on field \"Mutation.create_update\".",
        "locations": [{"line": 3, "column": 50}]
      }
    ],
    "extensions": {
      "request_id": "e6983c5d-5f4e-9009-a259-a15f7c4d4cd6"
    },
    "status": 200
  },
  "request": {
    "query": "\n  mutation createUpdate($itemId: ID!, $body: String!, $mentionsList: [UpdateMention]) {\n    create_update(item_id: $itemId, body: $body, mentions_list: $mentionsList) {\n      id\n    }\n  }\n",
    "variables": {
      "itemId": "10589669935",
      "body": "POC scope: Use trend relevance signals (category interest, browsing behavior) to identify target users. No sophisticated segmentation needed for December - focus is proving the workflow. Advanced segmentation comes post-POC."
    }
  }
}

GraphQL Query Generated by MCP Server

mutation createUpdate($itemId: ID!, $body: String!, $mentionsList: [UpdateMention]) {
  create_update(item_id: $itemId, body: $body, mentions_list: $mentionsList) {
    id
  }
}

Root Cause

The MCP server's GraphQL mutation hardcodes the $mentionsList: [UpdateMention] parameter and mentions_list: $mentionsList argument in the query, regardless of whether the user provides mention data.

Monday.com's API rejects this because:

1. ❌ The UpdateMention type does not exist in their current GraphQL schema
2. ❌ The mentions_list argument does not exist on the create_update mutation
3. The error message suggests UpdatePin exists, indicating the schema may have changed

Expected Behavior

According to Monday.com's official API documentation (https://developer.monday.com/api-reference/reference/updates), the create_update mutation should accept:

mutation {
  create_update(
    item_id: ID
    body: String!
    parent_id: ID
    original_creation_date: String
    use_app_info: Boolean
  ) {
    id
  }
}

Note: The documentation does NOT list mentions_list as a parameter for create_update.

Actual Behavior

The MCP server generates a mutation with:

• $mentionsList: [UpdateMention] parameter (type doesn't exist)
• mentions_list: $mentionsList argument (argument not supported)

This causes all create_update calls to fail, even when the user doesn't want to mention anyone.

Reproduction Steps

1. Install and configure @mondaydotcomorg/monday-api-mcp
2. Call the create_update tool:

mcp__monday-api-mcp__create_update({
  itemId: 10589669935,
  body: "Test update"
})

3. Observe GraphQL error about UpdateMention type

Suggested Fix

Option 1: Remove mentions_list entirely (if deprecated)

mutation createUpdate($itemId: ID!, $body: String!) {
  create_update(item_id: $itemId, body: $body) {
    id
  }
}

Option 2: Make mentions_list truly optional

If mentions functionality is still needed, the mutation should only include mentions_list when the user provides mention data:

// Pseudo-code for MCP server logic
const mutation = `
  mutation createUpdate($itemId: ID!, $body: String!${hasMentions ? ', $mentionsList: [UpdateMention]' : ''}) {
    create_update(
      item_id: $itemId
      body: $body
      ${hasMentions ? 'mentions_list: $mentionsList' : ''}
    ) {
      id
    }
  }
`;

Option 3: Update type definition to match current API

If Monday.com renamed UpdateMention to something else (e.g., UpdatePin), update the schema accordingly.

Impact

• Severity: High - create_update tool is completely broken
• Workaround: None available via MCP - users must skip creating updates/comments
• Affected Users: Anyone using the create_update tool

Additional Context

• Other MCP tools (create_item, change_item_column_values, move_item_to_group) work correctly
• The schema mismatch suggests the MCP server may be using an outdated GraphQL introspection schema
• This may affect other tools if they reference deprecated types

Verification

Tested against Monday.com's production API as of 2025-11-19. The official documentation does not list mentions_list as a supported parameter for create_update.

---

Would appreciate a fix or guidance on whether mentions functionality is still supported in Monday.com's API.