DynamoDB MCP Server

Instructions

Implementation Reference

• src/index.ts:334-364 (handler)

  The main handler function that implements the update_gsi tool logic by sending an UpdateTableCommand to update the provisioned throughput of a Global Secondary Index (GSI).

  async function updateGSI(params: any) {
    try {
      const command = new UpdateTableCommand({
        TableName: params.tableName,
        GlobalSecondaryIndexUpdates: [
          {
            Update: {
              IndexName: params.indexName,
              ProvisionedThroughput: {
                ReadCapacityUnits: params.readCapacity,
                WriteCapacityUnits: params.writeCapacity,
              },
            },
          },
        ],
      });
      
      const response = await dynamoClient.send(command);
      return {
        success: true,
        message: `GSI ${params.indexName} capacity updated on table ${params.tableName}`,
        details: response.TableDescription,
      };
    } catch (error) {
      console.error("Error updating GSI:", error);
      return {
        success: false,
        message: `Failed to update GSI: ${error}`,
      };
    }
  }

• src/index.ts:94-107 (schema)

  The Tool object definition for 'update_gsi', including the input schema for validation.

  const UPDATE_GSI_TOOL: Tool = {
    name: "update_gsi",
    description: "Updates the provisioned capacity of a global secondary index",
    inputSchema: {
      type: "object",
      properties: {
        tableName: { type: "string", description: "Name of the table" },
        indexName: { type: "string", description: "Name of the index to update" },
        readCapacity: { type: "number", description: "New read capacity units" },
        writeCapacity: { type: "number", description: "New write capacity units" },
      },
      required: ["tableName", "indexName", "readCapacity", "writeCapacity"],
    },
  };

• src/index.ts:598-600 (registration)

  Registration of the update_gsi tool (as UPDATE_GSI_TOOL) in the list of available tools returned by ListToolsRequest.

  server.setRequestHandler(ListToolsRequestSchema, async () => ({
    tools: [CREATE_TABLE_TOOL, UPDATE_CAPACITY_TOOL, PUT_ITEM_TOOL, GET_ITEM_TOOL, QUERY_TABLE_TOOL, SCAN_TABLE_TOOL, DESCRIBE_TABLE_TOOL, LIST_TABLES_TOOL, CREATE_GSI_TOOL, UPDATE_GSI_TOOL, CREATE_LSI_TOOL, UPDATE_ITEM_TOOL],
  }));

• src/index.ts:617-619 (registration)

  Switch case in the CallToolRequest handler that dispatches 'update_gsi' calls to the updateGSI function.

  case "update_gsi":
    result = await updateGSI(args);
    break;