feat: AJV tools

examples/ajv-tools/src/index.ts

@@ -2,8 +2,8 @@ import { serve } from '@hono/node-server'
 import { Hono } from 'hono';
 import { MCPServer } from "@zuplo/mcp/server";
 import { HTTPStreamableTransport } from "@zuplo/mcp/transport/httpstreamable";
-import Ajv, { JSONSchemaType } from 'ajv';
-import { CustomValidator } from '@zuplo/mcp/tools/custom';
+import { JSONSchemaType } from 'ajv';
+import { AjvValidator } from '@zuplo/mcp/tools/ajv';
 
 // Hono app for routing and handling fetch API Request / Response
 const app = new Hono();
@@ -14,8 +14,6 @@ const server = new MCPServer({
   version: "0.0.0",
 });
 
-const ajv = new Ajv();
-
 type NumberPair = { a: number; b: number };
 
 const numberPairSchema: JSONSchemaType<NumberPair> = {
@@ -28,23 +26,12 @@ const numberPairSchema: JSONSchemaType<NumberPair> = {
   additionalProperties: false,
 };
 
-const validateFn = ajv.compile<NumberPair>(numberPairSchema);
-
-const numberPairValidator = new CustomValidator<NumberPair>(
-  numberPairSchema,
-  (input) => {
-    if (validateFn(input)) {
-      return { success: true, data: input, error: null }
-    };
-
-    return { success: false, data: null, error: ajv.errorsText(validateFn.errors) }
-  }
-);
-
 server.addTool({
   name: "add",
   description: "Adds two numbers together",
-  validator: numberPairValidator,
+  validator: new AjvValidator<NumberPair>(
+    numberPairSchema
+  ),
   handler: async ({ a, b }) => ({
     content: [{ type: "text", text: String(a + b) }],
     isError: false,

examples/custom-validator/README.md

@@ -0,0 +1,42 @@
+# Custom Ajv validator
+
+This demonstrates using Ajv with the `CustomValidator` to in an advanced use case to:
+
+1. Build a custom schema validator function based on a concrete type / schema using `ajv.compile`
+2. Build a hand rolled, "bring your own validator" with `CustomValidator<T>`
+3. Provide the custom validator when bootstrapping a tool
+
+## 🏃 Build & run the server
+
+```
+npm i
+npm run build
+npm run start
+```
+
+## 🧠 Interact
+
+Use the [Model Context Protocol Inspector](https://github.com/modelcontextprotocol/inspector)
+and `localhost:3000/mcp`.
+
+```sh
+npx @modelcontextprotocol/inspector
+```
+
+or curl:
+
+```sh
+curl -X POST \
+  -H 'Accept: application/json' \
+  -d '{
+    method: "tools/call"
+    params:{
+      name: "add"
+      arguments:{
+        a: 1
+        b: 2
+      }
+    }
+  }' \
+  localhost:3000/mcp
+```

examples/custom-validator/package.json

@@ -0,0 +1,16 @@
+{
+  "name": "@zuplo/mcp example tools server",
+  "private": true,
+  "type": "module",
+  "scripts": {
+    "build": "tsc",
+    "start": "node dist/index.js"
+  },
+  "dependencies": {
+    "@hono/node-server": "^1.14.1",
+    "@zuplo/mcp": "file:../../",
+    "ajv": "^8.17.1",
+    "hono": "^4.7.9",
+    "json-schema-to-ts": "^3.1.1"
+  }
+}

examples/custom-validator/src/index.ts

@@ -0,0 +1,81 @@
+import { serve } from '@hono/node-server'
+import { Hono } from 'hono';
+import { MCPServer } from "@zuplo/mcp/server";
+import { HTTPStreamableTransport } from "@zuplo/mcp/transport/httpstreamable";
+import Ajv, { AnySchemaObject, JSONSchemaType } from 'ajv';
+import { CustomValidator } from '@zuplo/mcp/tools/custom';
+import { FromSchema } from "json-schema-to-ts";
+
+// Hono app for routing and handling fetch API Request / Response
+const app = new Hono();
+
+// MCP server
+const server = new MCPServer({
+  name: "Calculator",
+  version: "0.0.0",
+});
+
+const ajv = new Ajv();
+
+type NumberPair = { a: number; b: number };
+
+const numberPairSchema: JSONSchemaType<NumberPair> = {
+  type: "object",
+  properties: {
+    a: { type: "number" },
+    b: { type: "number" },
+  },
+  required: ["a", "b"],
+  additionalProperties: false,
+};
+
+// Infers the object type and schema from the validation function
+const validateFn = ajv.compile(numberPairSchema);
+
+console.log(validateFn.schema)
+
+const numberPairValidator = new CustomValidator<any>(
+  validateFn.schema as AnySchemaObject,
+  (input) => {
+    if (validateFn(input)) {
+      return { success: true, data: input, error: null }
+    };
+
+    return { success: false, data: null, error: ajv.errorsText(validateFn.errors) }
+  }
+);
+
+server.addTool({
+  name: "add",
+  description: "Adds two numbers together",
+  validator: numberPairValidator,
+  handler: async ({ a, b }) => ({
+    content: [{ type: "text", text: String(a + b) }],
+    isError: false,
+  }),
+});
+
+// HTTP Streamable Transport
+const transport = new HTTPStreamableTransport();
+await transport.connect();
+server.withTransport(transport);
+
+// Set up a POST route for MCP requests
+app.post('/mcp', async (c) => {
+  try {
+    const request = c.req.raw;
+    return transport.handleRequest(request);
+  } catch (error) {
+    console.error('Error handling MCP request:', error);
+    return new Response(JSON.stringify({ error: 'Internal server error' }), {
+      status: 500,
+      headers: { 'Content-Type': 'application/json' }
+    });
+  }
+});
+
+console.log("serving on port 3000")
+serve({
+  fetch: app.fetch,
+  port: 3000
+});

examples/custom-validator/tsconfig.json

@@ -0,0 +1,13 @@
+{
+  "extends": "../../tsconfig.base.json",
+  "compilerOptions": {
+    "outDir": "./dist",
+    "rootDir": "./src"
+  },
+  "include": [
+    "./src/**/*"
+  ],
+  "references": [
+    { "path": "../../" }
+  ]
+}