feat: migrate to MCP SDK v2, add you-answer tool, and bump deps

docs/PERFORMANCE.md

@@ -166,7 +166,7 @@ MCP servers (like `@youdotcom-oss/mcp`) have higher thresholds (100ms/50%/400KB)
 **MCP Server Overhead Sources**:
 - **Stdio transport**: Process IPC adds 20-40ms latency
 - **JSON-RPC protocol**: Serialization/deserialization adds 10-20ms
-- **Client SDK**: `@modelcontextprotocol/sdk` protocol overhead
+- **Client SDK**: `@modelcontextprotocol/client` protocol overhead
 - **Process spawning**: Each test spawns MCP server as subprocess
 - **State management**: Client state, connection pools, schemas
 

package.json

@@ -32,15 +32,15 @@
     ]
   },
   "devDependencies": {
-    "@biomejs/biome": "2.5.4",
+    "@biomejs/biome": "2.5.9",
     "@commitlint/cli": "^21.2.1",
     "@commitlint/config-conventional": "^21.2.0",
-    "@modelcontextprotocol/sdk": "^1.29.0",
+    "@modelcontextprotocol/client": "^2.0.0",
     "@types/bun": "latest",
     "format-package": "^8.0.0",
     "lint-staged": "^17.1.0",
     "typescript": "7.0.2",
     "typescript-language-server": "5.3.0",
-    "zod": "^4.3.6"
+    "zod": "^4.4.3"
   }
 }

packages/ai-sdk-plugin/README.md

@@ -1,6 +1,6 @@
 # Vercel AI SDK Plugin for You.com
 
-Give your AI applications **real-time access to the web** through the hosted You.com MCP server. This package exposes an async `createYouClient()` helper that connects to `https://api.you.com/mcp` and returns the underlying AI SDK MCP client. By default, `await client.tools()` resolves to the default hosted tool set: `you-search`, `you-contents`, `you-research`, `you-balance`, and `you-discover`.
+Give your AI applications **real-time access to the web** through the hosted You.com MCP server. This package exposes an async `createYouClient()` helper that connects to `https://api.you.com/mcp` and returns the underlying AI SDK MCP client. By default, `await client.tools()` resolves to the default hosted tool set: `you-search`, `you-contents`, `you-research`, `you-balance`, `you-discover`, and `you-answer`.
 
 ## Features
 
@@ -85,7 +85,7 @@ try {
 }
 ```
 
-`createYouClient()` returns the underlying MCP client. Call `await client.tools()` to resolve the default hosted tool set (`you-search`, `you-contents`, `you-research`, `you-balance`, and `you-discover`) unless you scope it with `tools`, and call `await client.close()` when finished.
+`createYouClient()` returns the underlying MCP client. Call `await client.tools()` to resolve the default hosted tool set (`you-search`, `you-contents`, `you-research`, `you-balance`, `you-discover`, and `you-answer`) unless you scope it with `tools`, and call `await client.close()` when finished.
 
 Set your You.com API key as an environment variable:
 
@@ -222,6 +222,7 @@ The default hosted tool set is:
 - `you-research`
 - `you-balance`
 - `you-discover`
+- `you-answer`
 
 Optional tools:
 
@@ -233,7 +234,7 @@ Optional tools:
 
 `profile` selects a hosted server profile. `tools` scopes which tools are visible. If `profile` is provided, it takes precedence over `tools`.
 
-Today, `profile: 'free'` is a search-only mode. It overrides `tools` and does not expose `you-contents`, `you-research`, `you-finance`, `you-balance`, `you-discover`, or livecrawl.
+Today, `profile: 'free'` is a search-only mode. It overrides `tools` and does not expose `you-contents`, `you-research`, `you-finance`, `you-balance`, `you-discover`, `you-answer`, or livecrawl.
 
 ### Using different model providers
 
@@ -309,6 +310,7 @@ Default tools:
 - `you-research`
 - `you-balance`
 - `you-discover`
+- `you-answer`
 
 Optional tools:
 

packages/ai-sdk-plugin/package.json

@@ -62,15 +62,14 @@
   },
   "types": "./dist/main.d.ts",
   "dependencies": {
-    "@ai-sdk/mcp": "^1.0.42",
-    "@modelcontextprotocol/sdk": "^1.29.0"
+    "@ai-sdk/mcp": "^2.0.34"
   },
   "peerDependencies": {
-    "ai": "^6.0.168"
+    "ai": "^7.0.0"
   },
   "devDependencies": {
-    "@ai-sdk/anthropic": "^3.0.71",
+    "@ai-sdk/anthropic": "^4.0.40",
     "@types/bun": "latest",
-    "ai": "^6.0.168"
+    "ai": "^7.0.70"
   }
 }

packages/api/README.md

@@ -109,6 +109,13 @@ export YDC_ALLOWED_TOOLS="you-search,you-research,you-contents"
 
 Explicit `allowedTools` takes precedence over `YDC_ALLOWED_TOOLS`.
 
+When neither `allowedTools` nor `YDC_ALLOWED_TOOLS` is provided and no `profile`
+is set, the package advertises every known tool by default
+(`?tools=<all known tool names>`). This keeps the typed surface truthful — every
+`KnownToolName` is callable on a default connection, including `you-finance`
+(which the server only exposes via an explicit `?tools=` filter). Pass
+`allowedTools` or a `profile` to narrow the set.
+
 ### Profiles and auth
 
 Set `profile` to route to a hosted profile (sent as `?profile=...`):

packages/api/package.json

@@ -42,7 +42,7 @@
   },
   "scripts": {
     "build": "bun run build:bundle && bun run build:types",
-    "build:bundle": "bun build src/main.ts --outdir dist --target node --external @modelcontextprotocol/sdk",
+    "build:bundle": "bun build src/main.ts --outdir dist --target node --external @modelcontextprotocol/client",
     "build:types": "tsc --project tsconfig.build.json --declaration --emitDeclarationOnly --noEmit false",
     "check": "bun run check:biome && bun run check:types && bun run check:package",
     "check:biome": "biome check",
@@ -56,9 +56,10 @@
   },
   "types": "./dist/main.d.ts",
   "dependencies": {
-    "@modelcontextprotocol/sdk": "^1.29.0"
+    "@modelcontextprotocol/client": "^2.0.0"
   },
   "devDependencies": {
+    "@modelcontextprotocol/server": "^2.0.0",
     "@types/bun": "latest"
   }
 }

packages/api/src/main.ts

@@ -1,22 +1,31 @@
-import { Client } from '@modelcontextprotocol/sdk/client/index.js'
-import { StreamableHTTPClientTransport } from '@modelcontextprotocol/sdk/client/streamableHttp.js'
+import { Client, StreamableHTTPClientTransport } from '@modelcontextprotocol/client'
 import packageJson from '../package.json' with { type: 'json' }
-import type { KnownToolInput, KnownToolName, KnownToolOutput } from './tool-schemas.ts'
+import {
+  API_TOOL_SCHEMA_HASH,
+  API_TOOL_SCHEMAS,
+  type KnownToolInput,
+  type KnownToolName,
+  type KnownToolOutput,
+} from './tool-schemas.ts'
 
 export type {
   KnownToolInput,
   KnownToolName,
   KnownToolOutput,
-  YouBalanceInput,
-  YouBalanceOutput,
+  YouAnswerInput,
+  YouAnswerOutput,
   YouContentsInput,
   YouContentsOutput,
+  YouDiscoverInput,
+  YouDiscoverOutput,
+  YouFinanceInput,
+  YouFinanceOutput,
   YouResearchInput,
   YouResearchOutput,
   YouSearchInput,
   YouSearchOutput,
 } from './tool-schemas.ts'
-export { API_TOOL_SCHEMA_HASH, API_TOOL_SCHEMAS } from './tool-schemas.ts'
+export { API_TOOL_SCHEMA_HASH, API_TOOL_SCHEMAS }
 
 const BASE_MCP_SERVER_URL = 'https://api.you.com/mcp'
 
@@ -41,8 +50,17 @@ const buildMcpUrl = ({ allowedTools, profile }: Pick<YouApiConfig, 'allowedTools
       : undefined
     : allowedTools || process.env.YDC_ALLOWED_TOOLS
 
+  // The api package is consumed imperatively (a caller wires specific tool
+  // calls), not by an agent browsing a tool list. So a connection with no
+  // explicit scope advertises every known tool by default — keeping the typed
+  // surface truthful, since every `KnownToolName` (including `you-finance`,
+  // which the server only exposes via an explicit `?tools=` filter) is callable
+  // on a default connection. A `profile` already scopes the tool set, so it is
+  // left to define the ceiling without an explicit `?tools=` override.
   if (tools) {
     url.searchParams.set('tools', tools)
+  } else if (!profile) {
+    url.searchParams.set('tools', Object.keys(API_TOOL_SCHEMAS).join(','))
   }
 
   return url

packages/api/src/tests/main.spec.ts

@@ -1,15 +1,18 @@
 import { afterEach, beforeEach, describe, expect, test } from 'bun:test'
-import { randomUUID } from 'node:crypto'
 import { mkdtempSync, readFileSync, rmSync } from 'node:fs'
 import { tmpdir } from 'node:os'
 import { join } from 'node:path'
-import { Server } from '@modelcontextprotocol/sdk/server/index.js'
-import { WebStandardStreamableHTTPServerTransport } from '@modelcontextprotocol/sdk/server/webStandardStreamableHttp.js'
-import { CallToolRequestSchema, ListToolsRequestSchema } from '@modelcontextprotocol/sdk/types.js'
+import { createMcpHandler, fromJsonSchema, type JsonSchemaType, McpServer } from '@modelcontextprotocol/server'
 import type { YouSearchInput, YouSearchOutput } from '../main.ts'
 import { createYouApi } from '../main.ts'
 
-const testTools = [
+type ToolSchema = {
+  properties?: Record<string, unknown>
+  required?: string[]
+  type: 'object'
+}
+
+const testTools: Array<{ inputSchema: ToolSchema; name: string; outputSchema?: ToolSchema }> = [
   {
     inputSchema: {
       properties: {
@@ -65,14 +68,6 @@ const testTools = [
   },
 ]
 
-const transports = new Map<
-  string,
-  {
-    server: Server
-    transport: WebStandardStreamableHTTPServerTransport
-  }
->()
-
 let originalFetch: typeof fetch
 let tempDir: string
 let traceFile: string
@@ -103,10 +98,6 @@ describe('createYouApi', () => {
       process.env.YDC_ALLOWED_TOOLS = originalAllowedTools
     }
 
-    await Promise.allSettled(
-      [...transports.values()].map(({ server, transport }) => Promise.all([server.close(), transport.close()])),
-    )
-    transports.clear()
     rmSync(tempDir, { force: true, recursive: true })
   })
 
@@ -174,7 +165,13 @@ describe('createYouApi', () => {
 
     expect(tools.tools.map(({ name }) => name)).toEqual(['you-contents', 'you-research', 'you-search'])
     const trace = readTrace()
-    expect(trace.every(({ url }) => url === 'https://api.you.com/mcp')).toBe(true)
+    expect(
+      trace.every(
+        ({ url }) =>
+          url ===
+          'https://api.you.com/mcp?tools=you-answer%2Cyou-contents%2Cyou-discover%2Cyou-finance%2Cyou-research%2Cyou-search',
+      ),
+    ).toBe(true)
     expect(trace.every(({ headers }) => headers.authorization === 'Bearer config-key')).toBe(true)
     await you.close()
   })
@@ -188,7 +185,13 @@ describe('createYouApi', () => {
     await you.tools()
 
     const trace = readTrace()
-    expect(trace.every(({ url }) => url === 'https://api.you.com/mcp')).toBe(true)
+    expect(
+      trace.every(
+        ({ url }) =>
+          url ===
+          'https://api.you.com/mcp?tools=you-answer%2Cyou-contents%2Cyou-discover%2Cyou-finance%2Cyou-research%2Cyou-search',
+      ),
+    ).toBe(true)
     await you.close()
   })
 
@@ -249,7 +252,7 @@ describe('createYouApi', () => {
 })
 
 const createTestServer = () => {
-  const server = new Server(
+  const mcp = new McpServer(
     {
       name: 'test-api-mcp-server',
       version: '1.0.0',
@@ -263,48 +266,55 @@ const createTestServer = () => {
     },
   )
 
-  server.setRequestHandler(ListToolsRequestSchema, async () => ({
-    tools: testTools,
-  }))
-  server.setRequestHandler(CallToolRequestSchema, async (request) => {
-    receivedToolInputs.push(request.params.arguments)
-
-    if (request.params.arguments?.query === 'missing-structured-content') {
-      return {
-        content: [],
-      }
-    }
+  for (const tool of testTools) {
+    mcp.registerTool(
+      tool.name,
+      {
+        inputSchema: fromJsonSchema(tool.inputSchema as JsonSchemaType),
+      },
+      async (args) => {
+        receivedToolInputs.push(args)
+        const query = (args as { query?: string } | undefined)?.query
+
+        if (query === 'missing-structured-content') {
+          return {
+            content: [],
+          }
+        }
 
-    if (request.params.arguments?.query === 'tool-error') {
-      return {
-        content: [],
-        isError: true,
-        structuredContent: {
-          message: 'Tool failed',
-        },
-      }
-    }
+        if (query === 'tool-error') {
+          return {
+            content: [],
+            isError: true,
+            structuredContent: {
+              message: 'Tool failed',
+            },
+          }
+        }
 
-    return {
-      content: [],
-      structuredContent: {
-        input: request.params.arguments,
-        ok: true,
+        return {
+          content: [],
+          structuredContent: {
+            input: args,
+            ok: true,
+          },
+        }
       },
-    }
-  })
+    )
+  }
 
-  return server
+  return mcp
 }
 
+const handler = createMcpHandler(createTestServer, { legacy: 'stateless' })
+
 const createMockedFetch = (activeTraceFile: string): typeof fetch =>
   Object.assign(
     async (input: string | URL | Request, init?: RequestInit | BunFetchRequestInit) => {
       const request =
         input instanceof Request
           ? new Request(input, init)
           : new Request(input instanceof URL ? input.toString() : input, init)
-      const sessionId = request.headers.get('mcp-session-id')
 
       await Bun.write(
         activeTraceFile,
@@ -315,31 +325,7 @@ const createMockedFetch = (activeTraceFile: string): typeof fetch =>
         })}\n`,
       )
 
-      if (sessionId) {
-        const activeTransport = transports.get(sessionId)?.transport
-
-        if (activeTransport) {
-          return activeTransport.handleRequest(request)
-        }
-      }
-
-      const server = createTestServer()
-      let transport!: WebStandardStreamableHTTPServerTransport
-
-      transport = new WebStandardStreamableHTTPServerTransport({
-        enableJsonResponse: true,
-        onsessionclosed: (closedSessionId) => {
-          transports.delete(closedSessionId)
-        },
-        onsessioninitialized: (initializedSessionId) => {
-          transports.set(initializedSessionId, { server, transport })
-        },
-        sessionIdGenerator: () => randomUUID(),
-      })
-
-      await server.connect(transport)
-
-      return transport.handleRequest(request)
+      return handler.fetch(request)
     },
     {
       preconnect: globalThis.fetch.preconnect.bind(globalThis.fetch),