MCP Datastore Server

Instructions

Implementation Reference

• src/datastore.ts:51-66 (handler)

  The main handler function that executes the datastore_query tool logic, creating and running a Google Cloud Datastore query for the given kind with optional limit and offset.

  async queryEntities(kind: string, limit = 100, offset = 0): Promise<any[]> {
    try {
      const query = this.datastore.createQuery(kind)
        .limit(limit)
        .offset(offset);
  
      const [entities] = await this.datastore.runQuery(query);
      
      return entities.map(entity => ({
        key: entity[this.datastore.KEY],
        ...entity,
      }));
    } catch (error) {
      throw new Error(`Failed to query entities: ${error instanceof Error ? error.message : 'Unknown error'}`);
    }
  }

• src/index.ts:58-79 (schema)

  Input schema and metadata definition for the datastore_query tool, used in ListTools response.

  {
    name: 'datastore_query',
    description: 'Execute a query on entities with optional filters',
    inputSchema: {
      type: 'object',
      properties: {
        kind: {
          type: 'string',
          description: 'The entity kind to query',
        },
        limit: {
          type: 'number',
          description: 'Maximum number of results to return (default: 100)',
        },
        offset: {
          type: 'number',
          description: 'Number of results to skip (default: 0)',
        },
      },
      required: ['kind'],
    },
  },

• src/index.ts:166-179 (registration)

  Dispatches the CallToolRequest for datastore_query to the queryEntities handler and formats the response.

  case 'datastore_query':
    const results = await datastoreClient.queryEntities(
      args.kind as string,
      args.limit as number | undefined,
      args.offset as number | undefined
    );
    return {
      content: [
        {
          type: 'text',
          text: JSON.stringify(results, null, 2),
        },
      ],
    };