Metabase MCP Server

Instructions

Implementation Reference

• src/server/handlers/fieldHandlers.js:42-61 (handler)

  The primary handler function for the 'get_field_values' MCP tool. It validates the fieldId, fetches distinct values from the Metabase API endpoint `/api/field/${fieldId}/values`, limits display to first 100 values, and returns a formatted MCP response.

    async getFieldValues(fieldId) {
      Validators.validateFieldId(fieldId);
      
      this.logger.debug('Getting field values', { fieldId });
      const values = await this.apiClient.makeRequest(`/api/field/${fieldId}/values`);
      
      const distinctValues = values.values || [];
      
      return {
        content: [
          {
            type: 'text',
            text: `Field Values (ID: ${fieldId}):
  Total Distinct Values: ${distinctValues.length}
  
  ${distinctValues.length > 0 ? `Values:\n${distinctValues.slice(0, 100).join(', ')}${distinctValues.length > 100 ? `\n... and ${distinctValues.length - 100} more values` : ''}` : 'No values found'}`,
          },
        ],
      };
    }

• src/server/config/toolDefinitions.js:234-248 (schema)

  The tool schema definition including name, description, and input validation schema requiring a single integer 'fieldId' parameter.

  {
    name: 'get_field_values',
    description: '🔍 [SAFE] Get distinct values for a field (useful for understanding what values exist in a column). May return many values for high-cardinality fields. Risk: None - read-only, but may return large results.',
    inputSchema: {
      type: 'object',
      properties: {
        fieldId: {
          type: 'integer',
          description: 'The ID of the field',
          minimum: 1,
        },
      },
      required: ['fieldId'],
    },
  },

• src/server/MetabaseMCPServer.js:212-213 (registration)

  The tool dispatch/registration in the MCP server's executeTool method switch statement, which routes calls to the FieldHandlers.getFieldValues method.

  case 'get_field_values':
    return await this.fieldHandlers.getFieldValues(args.fieldId);