improve mcp

Author: kentcdodds

app/routes/mcp+/fetch-transport.server.ts

@@ -1,4 +1,4 @@
-import { randomUUID } from 'node:crypto'
+// maybe this'll get built-into the SDK: https://github.com/modelcontextprotocol/typescript-sdk/issues/260
 import { type Transport } from '@modelcontextprotocol/sdk/shared/transport.js'
 import {
 	type JSONRPCMessage,
@@ -24,7 +24,7 @@ export class FetchSSEServerTransport implements Transport {
 	 */
 	constructor(endpoint: string, sessionId?: string | null) {
 		this.#endpoint = endpoint
-		this.#sessionId = sessionId ?? randomUUID()
+		this.#sessionId = sessionId ?? crypto.randomUUID()
 	}
 
 	/**

app/routes/mcp+/index.ts

@@ -1,3 +1,4 @@
+import { invariantResponse } from '@epic-web/invariant'
 import { type Route } from './+types/index.ts'
 import { connect, getTransport } from './mcp.server.ts'
 
@@ -11,12 +12,10 @@ export async function loader({ request }: Route.LoaderArgs) {
 export async function action({ request }: Route.ActionArgs) {
 	const url = new URL(request.url)
 	const sessionId = url.searchParams.get('sessionId')
-	if (!sessionId) {
-		return new Response('No session ID', { status: 400 })
-	}
+	invariantResponse(sessionId, 'No session ID')
+
 	const transport = await getTransport(sessionId)
-	if (!transport) {
-		return new Response('Not found', { status: 404 })
-	}
+	invariantResponse(transport, 'No transport', { status: 404 })
+
 	return transport.handlePostMessage(request)
 }

app/routes/mcp+/mcp.server.ts

@@ -20,6 +20,7 @@ export const server = new McpServer(
 
 server.tool(
 	'Find User',
+	'Search for users in the Epic Notes database by their name or username',
 	{ query: z.string().describe('The query to search for') },
 	async ({ query }) => {
 		const like = `%${query ?? ''}%`

package.json

@@ -22,6 +22,7 @@
     "setup": "npm run build && prisma migrate deploy && prisma generate --sql && playwright install",
     "start": "cross-env NODE_ENV=production node .",
     "start:mocks": "cross-env NODE_ENV=production MOCKS=true tsx .",
+    "test:mcp": "npx @modelcontextprotocol/inspector",
     "test": "vitest",
     "coverage": "vitest run --coverage",
     "test:e2e": "npm run test:e2e:dev --silent",