diff --git a/src/lib/auth/index.ts b/src/lib/auth/index.ts
index 82b68351..ddb80d8b 100644
--- a/src/lib/auth/index.ts
+++ b/src/lib/auth/index.ts
@@ -4,10 +4,104 @@ import { db } from "@/lib/db";
 import { getConfig } from "@/lib/config";
 import { initializePlugins, getAuthPlugin } from "@/lib/plugins";
 import type { User } from "@prisma/client";
+import type { Adapter, AdapterUser } from "next-auth/adapters";
 
 // Initialize plugins before use
 initializePlugins();
 
+// Generate a unique username from email or name
+async function generateUsername(email: string, name?: string | null): Promise<string> {
+  // Try to use the part before @ in email
+  let baseUsername = email.split("@")[0].toLowerCase().replace(/[^a-z0-9_]/g, "");
+  
+  // If too short, use name
+  if (baseUsername.length < 3 && name) {
+    baseUsername = name.toLowerCase().replace(/[^a-z0-9_]/g, "").slice(0, 15);
+  }
+  
+  // Ensure minimum length
+  if (baseUsername.length < 3) {
+    baseUsername = "user";
+  }
+  
+  // Check if username exists and append number if needed
+  let username = baseUsername;
+  let counter = 1;
+  while (await db.user.findUnique({ where: { username } })) {
+    username = `${baseUsername}${counter}`;
+    counter++;
+  }
+  
+  return username;
+}
+
+// Custom adapter that wraps PrismaAdapter to add username
+function CustomPrismaAdapter(): Adapter {
+  const prismaAdapter = PrismaAdapter(db);
+  
+  return {
+    ...prismaAdapter,
+    async createUser(data: AdapterUser & { username?: string }) {
+      // Use GitHub username if provided, otherwise generate one
+      let username = (data as any).username;
+      if (!username) {
+        username = await generateUsername(data.email, data.name);
+      } else {
+        username = username.toLowerCase();
+        
+        // Check if there's an unclaimed account with this username
+        const unclaimedEmail = `${username}@unclaimed.prompts.chat`;
+        const unclaimedUser = await db.user.findUnique({
+          where: { email: unclaimedEmail },
+        });
+        
+        if (unclaimedUser) {
+          // Claim this account - update with real user info
+          const claimedUser = await db.user.update({
+            where: { id: unclaimedUser.id },
+            data: {
+              name: data.name,
+              email: data.email,
+              avatar: data.image,
+              emailVerified: data.emailVerified,
+            },
+          });
+          
+          return {
+            ...claimedUser,
+            image: claimedUser.avatar,
+          } as AdapterUser;
+        }
+        
+        // Ensure GitHub username is unique, append number if taken
+        const baseUsername = username;
+        let finalUsername = baseUsername;
+        let counter = 1;
+        while (await db.user.findUnique({ where: { username: finalUsername } })) {
+          finalUsername = `${baseUsername}${counter}`;
+          counter++;
+        }
+        username = finalUsername;
+      }
+      
+      const user = await db.user.create({
+        data: {
+          name: data.name,
+          email: data.email,
+          avatar: data.image,
+          emailVerified: data.emailVerified,
+          username,
+        },
+      });
+      
+      return {
+        ...user,
+        image: user.avatar,
+      } as AdapterUser;
+    },
+  };
+}
+
 // Build auth config dynamically based on prompts.config.ts
 async function buildAuthConfig() {
   const config = await getConfig();
@@ -18,7 +112,7 @@ async function buildAuthConfig() {
   }
 
   return {
-    adapter: PrismaAdapter(db),
+    adapter: CustomPrismaAdapter(),
     providers: [authPlugin.getProvider()],
     session: {
       strategy: "jwt" as const,
diff --git a/src/lib/plugins/auth/github.ts b/src/lib/plugins/auth/github.ts
index 50e4f781..c209e206 100644
--- a/src/lib/plugins/auth/github.ts
+++ b/src/lib/plugins/auth/github.ts
@@ -8,5 +8,14 @@ export const githubPlugin: AuthPlugin = {
     GitHub({
       clientId: process.env.GITHUB_CLIENT_ID!,
       clientSecret: process.env.GITHUB_CLIENT_SECRET!,
+      profile(profile) {
+        return {
+          id: profile.id.toString(),
+          name: profile.name || profile.login,
+          email: profile.email,
+          image: profile.avatar_url,
+          username: profile.login, // GitHub username
+        };
+      },
     }),
 };