InstantDB MCP Server

import { Tool, ListToolsRequestSchema, CallToolRequestSchema, } from "@modelcontextprotocol/sdk/types.js"; import { Server } from "@modelcontextprotocol/sdk/server/index.js"; import { queryStore } from "../utils/queries.js"; import { listQueries } from "./listQueries.js"; import { serveExamples } from "./getExamples.js"; import { queryDB } from "./queryDB.js"; // Tool Definitions export const LIST_QUERIES_TOOL: Tool = { name: "list_queries", description: "List of recent queries that you performed via the MCP during this session", inputSchema: { type: "object", properties: { limit: { type: "number", description: "Limit the number of queries" }, }, }, }; export const QUERY_DB_TOOL: Tool = { name: "query_db", description: "Execute a database query", inputSchema: { type: "object", properties: { query: { type: "string", description: "Valid JSON string with double quotes", }, name: { type: "string", description: "A name for the query", }, }, required: ["query", "name"], }, }; export const GET_EXAMPLES_TOOL: Tool = { name: "get_examples", description: "Retrieve example queries for reference", inputSchema: { type: "object", properties: { category: { type: "string", description: "Category of examples to retrieve: admin, reading, linking, modeling", }, }, required: ["category"], }, outputSchema: { type: "object", properties: { content: { type: "array", items: { type: "object", properties: { type: { type: "string", enum: ["text"] }, text: { type: "string" }, }, required: ["type", "text"], }, description: "The example content", }, }, }, }; export const RETURN_QUERY_TOOL: Tool = { name: "return_query", description: "Return a query result from recent queries based on an identifier", inputSchema: { type: "object", properties: { id: { type: "string", description: "The query identifier", }, }, required: ["id"], }, }; // Aggregated tool definitions export const REGISTERED_TOOL_DEFINITIONS: Tool[] = [ LIST_QUERIES_TOOL, QUERY_DB_TOOL, GET_EXAMPLES_TOOL, RETURN_QUERY_TOOL, ]; /** * Registers all tool handlers with the provided MCP Server instance. * Each module's registration function will set up the necessary request handlers. */ export function registerAllTools(server: Server) { // Register a handler for listing tool definitions server.setRequestHandler(ListToolsRequestSchema, async () => { return { tools: REGISTERED_TOOL_DEFINITIONS }; }); // Register a handler for CallToolRequestSchema to log incoming tool calls server.setRequestHandler(CallToolRequestSchema, async (request) => { const toolName = request.params.name; const toolArgs = request.params.arguments || {}; console.error( `[MCP] Received tool call for: ${toolName} with arguments:`, toolArgs ); // Create the appropriate request object based on the tool name try { switch (toolName) { case "list_queries": const limit = toolArgs.limit ? toolArgs.limit : 50; console.error({ ...limit }); const queries = listQueries(limit as number); return { content: [{ type: "text", text: JSON.stringify(queries, null, 2) }], }; case "query_db": const queryResult = await queryDB({ name: toolArgs.name as string, query: toolArgs.query as string, }); return { content: [ { type: "text", text: JSON.stringify((queryResult as any).content, null, 2), }, ], }; case "get_examples": return serveExamples(toolArgs.category as string); case "return_query": const query = queryStore.getQuery(toolArgs.id as string); return { content: [{ type: "text", text: JSON.stringify(query, null, 2) }], }; default: throw new Error(`Unknown tool: ${toolName}`); } } catch (error) { console.error(`[MCP] Error handling tool call for ${toolName}:`, error); throw error; } }); }