chore: mcp cli

adamatti · adamatti · commit e21c79d612da · 2025-04-28T13:36:33.000-03:00
diff --git a/posts/2025/04/28-mcp-cli.md b/posts/2025/04/28-mcp-cli.md
@@ -0,0 +1,94 @@
+---
+title: MCP sample - CLI
+summary: A basic MCP sample for CLI with typescript
+date: "2025-04-25"
+slug: mcp-cli
+tags:
+  - typescript
+  - ai
+  - mcp
+---
+
+The idea here is not explain what MCP is, just show a sample:
+
+# Dependencies
+
+Install it with npm/yarn/pnpm:
+
+- @modelcontextprotocol/sdk
+- zod
+
+# Code
+
+```typescript
+import { Server } from "@modelcontextprotocol/sdk/server/index.js";
+import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
+import {
+  CallToolRequestSchema,
+  ListToolsRequestSchema,
+} from "@modelcontextprotocol/sdk/types.js";
+import { z } from "zod";
+
+const tools = [
+  {
+    name: "Sum",
+    description: "do a sum",
+    inputSchema: z.object({ x: z.number(), y: z.number() }),
+    handler: (args) => ({
+      content: [
+        { type: "text", text: `${args.x} + ${args.y} = ${args.x + args.y}` },
+      ],
+    }),
+  },
+];
+
+const server = new Server(
+  { name: "mcp-server", version: "0.0.1" },
+  { capabilities: { tools: {} } }
+);
+server.setRequestHandler(ListToolsRequestSchema, async () => {
+  return {
+    tools: tools.map((t) => ({
+      name: t.name,
+      description: t.description,
+      parameters: t.inputSchema,
+    })),
+  };
+});
+
+server.setRequestHandler(CallToolRequestSchema, async (request) => {
+  const { name, arguments: args } = request.params;
+
+  try {
+    const tool = tools.find((t) => t.name === name);
+    if (!tool) {
+      throw new Error(`Tool unknown: ${name}`);
+    }
+    return await tool.handler(args);
+  } catch (error) {
+    console.error(`Error executing tool ${name}:`, error);
+    throw error;
+  }
+});
+
+const main = async () => {
+  const transport = new StdioServerTransport();
+  await server.connect(transport);
+};
+
+main();
+```
+
+# Sample calling
+
+List tools:
+
+```sh
+echo '{"jsonrpc": "2.0", "id": 1, "method": "tools/list"}' | pnpm dlx tsx cli.ts
+```
+
+Executing operation:
+
+```sh
+echo '{"jsonrpc": "2.0", "id": 1, "method": "tools/call", "params": {"name": "Sum", "arguments": {"x": 1, "y": 2}}}' | pnpm dlx tsx cli.ts
+```
