diff --git a/sample-vault/.obsidian/plugins/leif/main.js b/sample-vault/.obsidian/plugins/leif/main.js
index dd596db..05ee5ce 100644
--- a/sample-vault/.obsidian/plugins/leif/main.js
+++ b/sample-vault/.obsidian/plugins/leif/main.js
@@ -1086,6 +1086,9 @@ var Wall = class {
     this.notes = notes;
   }
 };
+function wallLinkKey(contestId, kind) {
+  return `${contestId}-${kind}`;
+}
 
 // src/domain/entities/Contest.ts
 var Contest = class {
@@ -2244,10 +2247,10 @@ async function seedTceSpDemo(dataStore) {
       contestId: contest.id,
       wall: {
         noticeLinks: [
-          { id: `${contest.id}-notice`, label: contestSpec.wall.noticeLabel, url: contestSpec.wall.noticeUrl }
+          { id: wallLinkKey(contest.id, "notice"), label: contestSpec.wall.noticeLabel, url: contestSpec.wall.noticeUrl }
         ],
         examLinks: [
-          { id: `${contest.id}-exam`, label: contestSpec.wall.examLabel, url: contestSpec.wall.examUrl }
+          { id: wallLinkKey(contest.id, "exam"), label: contestSpec.wall.examLabel, url: contestSpec.wall.examUrl }
         ],
         subjectSnapshots: seededSubjects.map((subject, index) => ({
           subjectId: subject.id,
@@ -4280,14 +4283,14 @@ var WallTab = class {
       try {
         const noticeLink = noticeUrl.value ? [
           {
-            id: `${activeContest.id}-notice`,
+            id: wallLinkKey(activeContest.id, "notice"),
             label: noticeLabel.value || "Edital",
             url: noticeUrl.value
           }
         ] : [];
         const examLink = examUrl.value ? [
           {
-            id: `${activeContest.id}-exam`,
+            id: wallLinkKey(activeContest.id, "exam"),
             label: examLabel.value || "Prova",
             url: examUrl.value
           }
diff --git a/src/domain/entities/Wall.ts b/src/domain/entities/Wall.ts
index e1b7a4f..e56bcdc 100644
--- a/src/domain/entities/Wall.ts
+++ b/src/domain/entities/Wall.ts
@@ -41,4 +41,18 @@ export class Wall {
     public readonly subjectSnapshots: WallSubjectSnapshot[] = [],
     public readonly notes?: string
   ) {}
+}
+
+/**
+ * The kinds of single-link slots the wall form manages.
+ */
+export type WallLinkKind = "notice" | "exam";
+
+/**
+ * Builds the stable identifier used for the wall's single notice/exam link.
+ * The wall form overwrites the link on every save, so a deterministic id
+ * keeps the array at length 0 or 1 instead of appending duplicates.
+ */
+export function wallLinkKey(contestId: string, kind: WallLinkKind): string {
+  return `${contestId}-${kind}`;
 }
\ No newline at end of file
diff --git a/src/infrastructure/persistence/Seeder.ts b/src/infrastructure/persistence/Seeder.ts
index 9cc26f0..d0647ca 100644
--- a/src/infrastructure/persistence/Seeder.ts
+++ b/src/infrastructure/persistence/Seeder.ts
@@ -11,6 +11,7 @@ import type { StudyItem } from "@/domain/entities/StudyItem";
 import { StudySessionType } from "@/domain/entities/StudySession";
 import type { Subject } from "@/domain/entities/Subject";
 import type { Topic } from "@/domain/entities/Topic";
+import { wallLinkKey } from "@/domain/entities/Wall";
 import { EntityRepositoryFactory } from "@/infrastructure/persistence/EntityRepositoryFactory";
 
 export interface SeededContest {
@@ -469,10 +470,10 @@ export async function seedTceSpDemo(dataStore: PluginDataStore): Promise<SeededC
       contestId: contest.id,
       wall: {
         noticeLinks: [
-          { id: `${contest.id}-notice`, label: contestSpec.wall.noticeLabel, url: contestSpec.wall.noticeUrl }
+          { id: wallLinkKey(contest.id, "notice"), label: contestSpec.wall.noticeLabel, url: contestSpec.wall.noticeUrl }
         ],
         examLinks: [
-          { id: `${contest.id}-exam`, label: contestSpec.wall.examLabel, url: contestSpec.wall.examUrl }
+          { id: wallLinkKey(contest.id, "exam"), label: contestSpec.wall.examLabel, url: contestSpec.wall.examUrl }
         ],
         subjectSnapshots: seededSubjects.map((subject, index) => ({
           subjectId: subject.id,
diff --git a/src/ui/view/components/WallTab.ts b/src/ui/view/components/WallTab.ts
index 963ee1a..e2f3498 100644
--- a/src/ui/view/components/WallTab.ts
+++ b/src/ui/view/components/WallTab.ts
@@ -1,6 +1,7 @@
 import type { PluginDataStore } from "@/application/ports/PluginDataStore";
 import { UpdateContestWallUseCase } from "@/application/use-cases/UpdateContestWallUseCase";
 import type { LeifPluginData } from "@/domain/types/LeifPluginData";
+import { wallLinkKey } from "@/domain/entities/Wall";
 import { DomHelpers } from "@/ui/view/shared/DomHelpers";
 import { EntityRepositoryFactory } from "@/infrastructure/persistence/EntityRepositoryFactory";
 
@@ -71,7 +72,7 @@ export class WallTab {
         const noticeLink = noticeUrl.value
           ? [
               {
-                id: `${activeContest.id}-notice`,
+                id: wallLinkKey(activeContest.id, "notice"),
                 label: noticeLabel.value || "Edital",
                 url: noticeUrl.value
               }
@@ -81,7 +82,7 @@ export class WallTab {
         const examLink = examUrl.value
           ? [
               {
-                id: `${activeContest.id}-exam`,
+                id: wallLinkKey(activeContest.id, "exam"),
                 label: examLabel.value || "Prova",
                 url: examUrl.value
               }
diff --git a/tests/domain/EntityClasses.test.ts b/tests/domain/EntityClasses.test.ts
index e0ec21b..bb3382b 100644
--- a/tests/domain/EntityClasses.test.ts
+++ b/tests/domain/EntityClasses.test.ts
@@ -8,7 +8,7 @@ import { Topic } from "@/domain/entities/Topic";
 import { StudySession } from "@/domain/entities/StudySession";
 import { QuestionNotebook } from "@/domain/entities/QuestionNotebook";
 import { ResourceReference } from "@/domain/entities/ResourceReference";
-import { WallLink, WallSubjectSnapshot, Wall } from "@/domain/entities/Wall";
+import { WallLink, WallSubjectSnapshot, Wall, wallLinkKey } from "@/domain/entities/Wall";
 import { ValidationError } from "@/domain/errors/DomainErrors";
 
 describe("Entity Classes", () => {
@@ -142,6 +142,20 @@ describe("Entity Classes", () => {
     });
   });
 
+  describe("wallLinkKey", () => {
+    it("builds a stable notice-link id from the contest id", () => {
+      expect(wallLinkKey("c-1", "notice")).toBe("c-1-notice");
+    });
+
+    it("builds a stable exam-link id from the contest id", () => {
+      expect(wallLinkKey("c-1", "exam")).toBe("c-1-exam");
+    });
+
+    it("returns the same id for the same contest + kind", () => {
+      expect(wallLinkKey("c-1", "notice")).toBe(wallLinkKey("c-1", "notice"));
+    });
+  });
+
   describe("ContestState", () => {
     it("creates a valid state", () => {
       const state = new ContestState("c-1", "s-1", "i-1");