diff --git a/apps/web/package.json b/apps/web/package.json
index 84d0973..01e0acb 100644
--- a/apps/web/package.json
+++ b/apps/web/package.json
@@ -16,12 +16,16 @@
 		"@sveltejs/adapter-vercel": "^6.3.4",
 		"@sveltejs/kit": "^2.63.0",
 		"@sveltejs/vite-plugin-svelte": "^7.1.2",
+		"@types/node": "^20.19.43",
 		"svelte": "^5.56.1",
 		"svelte-check": "^4.6.0",
 		"typescript": "^6.0.3",
 		"vite": "^8.0.16"
 	},
 	"dependencies": {
-		"@duck/types": "workspace:*"
+		"@duck/types": "workspace:*",
+		"@modelcontextprotocol/server": "^2.0.0",
+		"mcp-handler": "^2.1.1",
+		"zod": "^4.5.4"
 	}
 }
diff --git a/apps/web/src/lib/mcp.ts b/apps/web/src/lib/mcp.ts
new file mode 100644
index 0000000..02eff79
--- /dev/null
+++ b/apps/web/src/lib/mcp.ts
@@ -0,0 +1,40 @@
+import type { McpServer } from "@modelcontextprotocol/server";
+import { z } from "zod";
+
+export const QUACK_TOOL_NAME = "quack";
+
+const QUACKS = {
+  happy: ["QUACK! 🎉", "Quack quack! 😄", "QUAAACK! 🦆✨"],
+  confused: ["Qu...ack?", "Quack? 🤔", "Quaaack...?"],
+  excited: ["QUACK QUACK QUACK!", "QUAAACK!! 🔥", "Quack! Quack! Quack!"],
+  sleepy: ["quack... 😴", "quaack... 💤", "quack. *yawn*"],
+  default: ["Quack!", "Quack quack!", "QUACK!", "Quaaack!", "Quack. 🦆"],
+} as const;
+
+const MOODS = ["happy", "confused", "excited", "sleepy"] as const;
+
+function randomFrom<T>(arr: readonly T[]): T {
+  return arr[Math.floor(Math.random() * arr.length)];
+}
+
+export function registerDuckTools(server: McpServer): void {
+  server.registerTool(
+    QUACK_TOOL_NAME,
+    {
+      title: "Quack",
+      description:
+        "Rubber duck quacks. Use when you're stuck, looping, or hallucinating. " +
+        "The act of calling forces you to articulate your current thinking out loud.",
+      inputSchema: z.object({
+        mood: z
+          .enum(MOODS)
+          .optional()
+          .describe("Mood of the duck. Omit for a random quack."),
+      }),
+    },
+    async ({ mood }) => {
+      const text = mood ? randomFrom(QUACKS[mood]) : randomFrom(QUACKS.default);
+      return { content: [{ type: "text", text }] };
+    },
+  );
+}
diff --git a/apps/web/src/routes/api/mcp/+server.ts b/apps/web/src/routes/api/mcp/+server.ts
new file mode 100644
index 0000000..cb3014f
--- /dev/null
+++ b/apps/web/src/routes/api/mcp/+server.ts
@@ -0,0 +1,20 @@
+import type { RequestEvent } from "@sveltejs/kit";
+import { createMcpHandler } from "mcp-handler";
+import { registerDuckTools } from "$lib/mcp";
+
+const handler = createMcpHandler(
+  async (server) => {
+    registerDuckTools(server);
+  },
+  {
+    serverInfo: { name: "rubber-duck-mcp", version: "1.0.0" },
+  },
+);
+
+export function GET(event: RequestEvent): Promise<Response> {
+  return handler(event.request);
+}
+
+export function POST(event: RequestEvent): Promise<Response> {
+  return handler(event.request);
+}
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 2ff8dea..996eeb7 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -268,6 +268,15 @@ importers:
       '@duck/types':
         specifier: workspace:*
         version: link:../../packages/types
+      '@modelcontextprotocol/server':
+        specifier: ^2.0.0
+        version: 2.0.0
+      mcp-handler:
+        specifier: ^2.1.1
+        version: 2.1.1(@modelcontextprotocol/server@2.0.0)(next@16.3.3(@types/node@20.19.43)(react-dom@19.2.8(react@19.2.8))(react@19.2.8))
+      zod:
+        specifier: ^4.5.4
+        version: 4.5.4
     devDependencies:
       '@sveltejs/adapter-vercel':
         specifier: ^6.3.4
@@ -278,6 +287,9 @@ importers:
       '@sveltejs/vite-plugin-svelte':
         specifier: ^7.1.2
         version: 7.3.0(svelte@5.57.0)(vite@8.2.2(@types/node@20.19.43)(esbuild@0.28.2)(tsx@4.23.13))
+      '@types/node':
+        specifier: ^20.19.43
+        version: 20.19.43
       svelte:
         specifier: ^5.56.1
         version: 5.57.0