Lightweight GitHub MCP

import { Client } from "@modelcontextprotocol/sdk/client/index.js"; import { StdioClientTransport } from "@modelcontextprotocol/sdk/client/stdio.js"; import type { Tool } from "@modelcontextprotocol/sdk/types.js"; import type { UpstreamConfig } from "./types.js"; export class UpstreamClient { private client: Client; private transport: StdioClientTransport | null = null; private config: UpstreamConfig; private connected = false; constructor(config: UpstreamConfig) { this.config = config; this.client = new Client( { name: "lightweight-github-proxy", version: "1.0.0" }, { capabilities: {} } ); } async connect(): Promise<void> { if (this.connected) { return; } // Launch upstream MCP as child process this.transport = new StdioClientTransport({ command: this.config.command, args: this.config.args, env: { ...process.env, // GITHUB_PERSONAL_ACCESS_TOKEN is inherited from environment variables } as Record<string, string>, }); await this.client.connect(this.transport); this.connected = true; } async listTools(): Promise<Tool[]> { if (!this.connected) { throw new Error("UpstreamClient is not connected"); } const result = await this.client.listTools(); return result.tools; } async callTool( name: string, args: Record<string, unknown> ): Promise<{ content: Array<{ type: string; text: string }> }> { if (!this.connected) { throw new Error("UpstreamClient is not connected"); } const result = await this.client.callTool({ name, arguments: args }); return result as { content: Array<{ type: string; text: string }> }; } async disconnect(): Promise<void> { if (!this.connected) { return; } try { await this.client.close(); } catch { // Ignore errors during disconnect } this.connected = false; } isConnected(): boolean { return this.connected; } }