MCP Server Starter

import "dotenv/config"; import { Client } from "@modelcontextprotocol/sdk/client/index.js"; import { StdioClientTransport } from "@modelcontextprotocol/sdk/client/stdio.js"; import { ListToolsResultSchema, CallToolResultSchema, } from "@modelcontextprotocol/sdk/types.js"; async function main() { // Spawn the server via tsx for dev convenience const transport = new StdioClientTransport({ command: process.platform === "win32" ? "npx.cmd" : "npx", args: ["tsx", "src/server/stdio.ts"], }); const client = new Client({ name: "dev-client", version: "0.1.0" }); await client.connect(transport); // === tools/list === const toolsResp = await client.request( { method: "tools/list", params: {} }, ListToolsResultSchema ); const toolNames = toolsResp.tools.map(t => t.name); console.log("Available tools:", toolNames); // --- NEW: auto-detect alias (optionally honoring DEV_DB_ALIAS) const preferred = process.env.DEV_DB_ALIAS?.trim(); const alias = pickAlias(toolNames, preferred); if (!alias) { throw new Error( "No namespaced SQL tools found (expected '<alias>.sql.schema'). " + "Check your dbs.yaml and environment." ); } console.log("Using DB alias:", alias, preferred ? `(preferred=${preferred})` : ""); // === tools/call: <alias>.sql.schema === const schemaRes = await client.request( { method: "tools/call", params: { name: `${alias}.sql.schema`, arguments: {}, }, }, CallToolResultSchema ); console.log( "\n=== sql.schema ===\n", schemaRes.content?.[0]?.type === "text" ? schemaRes.content[0].text : schemaRes ); // === tools/call: <alias>.sql.peek === const peekRes = await client.request( { method: "tools/call", params: { name: `${alias}.sql.peek`, arguments: { maxRowsPerTable: 50, // adjust if needed as: "json", }, }, }, CallToolResultSchema ); console.log( "\n=== sql.peek ===\n", peekRes.content?.[0]?.type === "text" ? peekRes.content[0].text : JSON.stringify(peekRes, null, 2) ); // === tools/call: <alias>.sql.query === const sample = detectSampleQuery(); const queryRes = await client.request( { method: "tools/call", params: { name: `${alias}.sql.query`, arguments: { sql: sample.text, params: sample.params, readOnly: true, rowLimit: 10, as: "json", }, }, }, CallToolResultSchema ); console.log( "\n=== sql.query ===\n", queryRes.content?.[0]?.type === "text" ? queryRes.content[0].text : queryRes ); await client.close(); } // --- NEW: helper to pick a valid alias from tools/list (with optional preferred) function pickAlias(names: string[], preferred?: string | null): string | null { const aliases = Array.from(new Set(names.map(n => n.split(".")[0]))); const hasSchema = (a: string) => names.includes(`${a}.sql.schema`); if (preferred && aliases.includes(preferred) && hasSchema(preferred)) { return preferred; } const first = aliases.find(hasSchema) ?? null; if (!first) { console.warn("No alias exposes '.sql.schema'. Found aliases:", aliases); } return first; } function detectSampleQuery() { const provider = (process.env.DB_PROVIDER ?? "sqlite").toLowerCase(); if (provider.includes("oracle")) return { text: "SELECT 1 AS one FROM dual", params: {} }; return { text: "SELECT 1 AS one", params: {} }; } main().catch((err) => { console.error("[dev-client] error:", err); process.exit(1); });