diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index b087abab..e0491c63 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -22,7 +22,13 @@ Before getting started, please **star our repository** to show your support for
 
 - Browse our open issues.
 - If you find an issue you want to work on, comment on it expressing your interest and wait to be officially assigned by a maintainer.
-- ⚠️ **Do not start coding or open a Pull Request before being assigned to the issue.** Unassigned PRs or PRs targeting unclaimed issues may be closed without review to avoid duplicate work.
+- ⚠️ **Do not start coding or open a Pull Request before being assigned to the issue.**
+- **Strict Issue Claiming & Pull Request Rules:**
+  - **Claim Before Coding:** You must officially claim and be assigned an issue before you start working on it or submit a Pull Request.
+  - **Priority for Rule Followers:** If a contributor submits a PR without being assigned to the issue, and another contributor subsequently requests to claim/work on that issue following the correct procedure (commenting on the issue to request assignment), priority will be given to the contributor who requested the claim.
+  - **Unassigned PR Procedure:** If a PR is opened without an associated claim/assignment, maintainers will post a comment on the corresponding issue directing the author to claim it.
+  - **7-Day Grace Period:** Maintainers will wait for up to **7 days** for the PR author to claim the issue. If the author fails to comment on the issue and claim it within 7 days, the PR may not be merged (even if the code is correct) and may be closed.
+  - **Claim Priority:** If another contributor claims the issue during this grace period, the contributor who officially requested the claim will be considered first.
 
 ### 3. Fork & Clone 🍴
 
diff --git a/README.md b/README.md
index 19c018e0..986a1c15 100644
--- a/README.md
+++ b/README.md
@@ -168,7 +168,7 @@ VeriWorkly is built on open-source principles, and we welcome community contribu
 > Before checking out a branch or creating a pull request, please review our full **[Contributing Guidelines](CONTRIBUTING.md)**.
 >
 > 1. 🌟 **Star the repository** to show your support.
-> 2. 📋 **Claim an issue** by commenting on it and waiting to be assigned before starting work.
+> 2. 📋 **Claim an issue** by commenting on it and waiting to be assigned before starting work. **PRs submitted for unclaimed/unassigned issues will not be merged unless claimed. Authors have a 7-day grace period to claim them, otherwise they may be closed. Priority always goes to the contributor who officially requested the claim.**
 > 3. 📝 Ensure your **PR titles** follow the standard naming convention.
 
 ### Ways to Help Out
diff --git a/apps/docs-platform/content/docs/contributing/index.mdx b/apps/docs-platform/content/docs/contributing/index.mdx
index 41befb33..0adef688 100644
--- a/apps/docs-platform/content/docs/contributing/index.mdx
+++ b/apps/docs-platform/content/docs/contributing/index.mdx
@@ -15,6 +15,20 @@ To ensure a smooth collaboration, please follow these steps to set up your contr
 
 1. **Star the Repository** 🌟: Before getting started, please star the [VeriWorkly Repository](https://github.com/VeriWorkly/veriworkly) to show your support for this open-source project!
 2. **Claim an Issue** 📋: Browse our open issues. Comment on the one you would like to work on and wait to be officially assigned by a maintainer. **Please do not start coding or open a PR until you are officially assigned to the issue** to avoid duplicate efforts.
+
+   <Callout type="warn" title="Issue Claiming & PR Policy">
+     * **Priority for Rule Followers:** If a contributor submits a PR without being assigned to the
+     issue, and another contributor subsequently requests to claim/work on that issue following the
+     correct procedure (commenting on the issue), priority will be given to the contributor who
+     requested the claim. * **No-Claim PR Procedure:** If a PR is opened without an associated
+     claim/assignment, maintainers will post a comment on the corresponding issue directing the
+     author to claim it. * **7-Day Grace Period:** Maintainers will wait for up to **7 days** for
+     the PR author to claim the issue. If the author fails to comment on the issue and claim it
+     within 7 days, the PR may not be merged (even if the code is correct) and may be closed. *
+     **Claim Priority:** If another contributor claims the issue during this grace period, the
+     contributor who officially requested the claim will be considered first.
+   </Callout>
+
 3. **Fork the repository** on GitHub by clicking the **Fork** button on the [VeriWorkly Repository](https://github.com/VeriWorkly/veriworkly).
 4. **Clone your personal fork** to your local machine:
    ```bash
diff --git a/apps/server/src/auth/index.ts b/apps/server/src/auth/index.ts
index 5fb0f758..e5f0049f 100644
--- a/apps/server/src/auth/index.ts
+++ b/apps/server/src/auth/index.ts
@@ -11,7 +11,7 @@ import { prisma } from "#utils/prisma";
 import { sendAuthOtpEmail } from "#auth/mailer";
 
 import { createAuthMiddleware } from "better-auth/api";
-import { invalidateSessionCache } from "#utils/authCache";
+import { invalidateSessionCache, invalidateCacheByToken } from "#utils/authCache";
 
 export const auth = betterAuth({
   database: prismaAdapter(prisma, {
@@ -83,6 +83,37 @@ export const auth = betterAuth({
       }
     }),
   },
+
+  databaseHooks: {
+    user: {
+      delete: {
+        before: async (user) => {
+          try {
+            const sessions = await prisma.session.findMany({
+              where: { userId: user.id },
+              select: { token: true },
+            });
+
+            await Promise.all(sessions.map((session) => invalidateCacheByToken(session.token)));
+          } catch {
+            // Ignore database hook errors to avoid blocking deletes
+          }
+        },
+      },
+    },
+
+    session: {
+      delete: {
+        after: async (session) => {
+          try {
+            await invalidateCacheByToken(session.token);
+          } catch {
+            // Ignore database hook errors to avoid blocking deletes
+          }
+        },
+      },
+    },
+  },
 });
 
 export const authNodeHandler = toNodeHandler(auth);
diff --git a/apps/server/src/utils/authCache.ts b/apps/server/src/utils/authCache.ts
index 66003d77..09a3dc70 100644
--- a/apps/server/src/utils/authCache.ts
+++ b/apps/server/src/utils/authCache.ts
@@ -42,3 +42,13 @@ export async function invalidateSessionCache(cookieHeader: string): Promise<void
     await cacheDel(cacheKey);
   }
 }
+
+export async function invalidateCacheByToken(token: string): Promise<void> {
+  const prefix1 = `veriworkly-auth.session_token=${token}`;
+  const prefix2 = `__Secure-veriworkly-auth.session_token=${token}`;
+
+  const hash1 = createHash("md5").update(prefix1).digest("hex");
+  const hash2 = createHash("md5").update(prefix2).digest("hex");
+
+  await Promise.all([cacheDel(`auth:session:${hash1}`), cacheDel(`auth:session:${hash2}`)]);
+}