[BUG] Google Sheets Integration - Read Operations Returning structuredContent Validation Errors

[JonasJesus42]

📋 Issue Description

The Google Sheets MCP integration has partial functionality issues. While write operations (CREATE, UPDATE) work perfectly, all read operations are failing with MCP schema validation errors.

🔴 Affected Tools (Read Operations)

The following tools are returning invalid_type: structuredContent null validation errors:

• GET_SPREADSHEET_VALUES - Error: structuredContent null
• QUERY_SPREADSHEET_DATA - Error: structuredContent null
• GET_SHEET_HEADERS - Error: structuredContent null
• GET_SPREADSHEET_METADATA - Error: structuredContent null
• GET_EMPTY_COLUMN - Error: structuredContent null
• GET_BATCH_SPREADSHEET_VALUES - Error: structuredContent null
• ADD_FORMULA - Error: http 500

✅ Working Operations (Write)

These operations function correctly:

• CREATE_SPREADSHEET - Working
• UPDATE_SPREADSHEET_VALUES - Working (Insert/Update)
• Google Drive integration - Working (Search, Create Files)

📊 Test Results

Success Rate: 63.6% (7 of 11 operations)

Write Operations Status

All write operations successfully:

• Created multiple spreadsheets with various sheets
• Inserted bulk data
• Updated existing records
• Integrated with Google Drive

Read Operations Status

All read operations fail at MCP schema validation layer with:

invalid_type: structuredContent null

🔍 Root Cause Analysis

This appears to be an MCP schema initialization issue related to the structuredContent field in response schemas. Similar patterns have been observed in other integrations (e.g., PNCP integration).

💡 Recommendations

1. Investigate MCP schema initialization for read-operation tools
2. Verify structuredContent field mapping in output schemas
3. Check tool response transformers for null value handling
4. Add schema validation tests for both write and read operations

🔗 Related Information

• Integration: Google Sheets (i:c94f679b-2095-428c-b93c-fa06900d9872)
• Supporting Integration: Google Drive (i:05a2435f-8e55-4999-8215-91103b8db4af)
• Test Date: November 7, 2025
• Pattern: Same as observed in PNCP integration issues

📝 Notes

No sensitive data included in this report. Testing was performed with generic spreadsheet data and product catalogs.