create_gsi

Instructions

Implementation Reference

• src/index.ts:290-332 (handler)

  The handler function that implements the core logic of the 'create_gsi' tool by constructing and sending an UpdateTableCommand to DynamoDB to create a Global Secondary Index.

  async function createGSI(params: any) {
    try {
      const command = new UpdateTableCommand({
        TableName: params.tableName,
        AttributeDefinitions: [
          { AttributeName: params.partitionKey, AttributeType: params.partitionKeyType },
          ...(params.sortKey ? [{ AttributeName: params.sortKey, AttributeType: params.sortKeyType }] : []),
        ],
        GlobalSecondaryIndexUpdates: [
          {
            Create: {
              IndexName: params.indexName,
              KeySchema: [
                { AttributeName: params.partitionKey, KeyType: "HASH" as const },
                ...(params.sortKey ? [{ AttributeName: params.sortKey, KeyType: "RANGE" as const }] : []),
              ],
              Projection: {
                ProjectionType: params.projectionType,
                ...(params.projectionType === "INCLUDE" ? { NonKeyAttributes: params.nonKeyAttributes } : {}),
              },
              ProvisionedThroughput: {
                ReadCapacityUnits: params.readCapacity,
                WriteCapacityUnits: params.writeCapacity,
              },
            },
          },
        ],
      });
      
      const response = await dynamoClient.send(command);
      return {
        success: true,
        message: `GSI ${params.indexName} creation initiated on table ${params.tableName}`,
        details: response.TableDescription,
      };
    } catch (error) {
      console.error("Error creating GSI:", error);
      return {
        success: false,
        message: `Failed to create GSI: ${error}`,
      };
    }
  }

• src/index.ts:73-92 (schema)

  The tool object definition for 'create_gsi', including name, description, and detailed inputSchema for parameter validation.

  const CREATE_GSI_TOOL: Tool = {
    name: "create_gsi",
    description: "Creates a global secondary index on a table",
    inputSchema: {
      type: "object",
      properties: {
        tableName: { type: "string", description: "Name of the table" },
        indexName: { type: "string", description: "Name of the new index" },
        partitionKey: { type: "string", description: "Partition key for the index" },
        partitionKeyType: { type: "string", enum: ["S", "N", "B"], description: "Type of partition key" },
        sortKey: { type: "string", description: "Sort key for the index (optional)" },
        sortKeyType: { type: "string", enum: ["S", "N", "B"], description: "Type of sort key (optional)" },
        projectionType: { type: "string", enum: ["ALL", "KEYS_ONLY", "INCLUDE"], description: "Type of projection" },
        nonKeyAttributes: { type: "array", items: { type: "string" }, description: "Non-key attributes to project (optional)" },
        readCapacity: { type: "number", description: "Provisioned read capacity units" },
        writeCapacity: { type: "number", description: "Provisioned write capacity units" },
      },
      required: ["tableName", "indexName", "partitionKey", "partitionKeyType", "projectionType", "readCapacity", "writeCapacity"],
    },
  };

• src/index.ts:598-600 (registration)

  Registers the CREATE_GSI_TOOL in the list of available tools served by the MCP server in response to 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:614-616 (registration)

  Dispatch/registration case in the CallToolRequestHandler switch statement that invokes the createGSI handler for the 'create_gsi' tool.

  case "create_gsi":
    result = await createGSI(args);
    break;