DynamoDB Read-Only MCP

Instructions

Implementation Reference

• src/dynamo-helpers.ts:148-163 (handler)

  Core implementation of the get-item tool logic using AWS SDK's GetItemCommand to retrieve a single item from DynamoDB.

  export async function getItem(tableName: string, key: Record<string, any>) {
    console.error('# Starting getItem function:', { tableName, key });
    try {
      const command = new GetItemCommand({
        TableName: tableName,
        Key: key,
      });
      console.error('# GetItem command created successfully');
      const response = await dynamodb.send(command);
      console.error('# GetItem response received:', response);
      return response.Item;
    } catch (error) {
      console.error('# Error in getItem function:', error);
      throw error;
    }
  }

• src/index.ts:255-258 (schema)

  Zod input schema defining parameters for the get-item tool: tableName and key.

  {
    tableName: z.string().describe('Table name'),
    key: z.record(z.any()).describe('Item key (JSON format)'),
  },

• src/index.ts:252-292 (registration)

  MCP server tool registration for 'get-item', including description, schema, and handler wrapper that calls the core getItem function.

  server.tool(
    'get-item',
    'Get an item from a DynamoDB table based on a specific key',
    {
      tableName: z.string().describe('Table name'),
      key: z.record(z.any()).describe('Item key (JSON format)'),
    },
    async ({ tableName, key }) => {
      try {
        const item = await getItem(tableName, key);
        if (!item) {
          return {
            content: [
              {
                type: 'text',
                text: 'Could not find the corresponding item.',
              },
            ],
          };
        }
        return {
          content: [
            {
              type: 'text',
              text: JSON.stringify(item, null, 2),
            },
          ],
        };
      } catch (error: any) {
        return {
          isError: true,
          content: [
            {
              type: 'text',
              text: `Error occurred: ${error.message}`,
            },
          ],
        };
      }
    }
  );