diff --git a/src/cli/hook.ts b/src/cli/hook.ts
index 532e5c7..677dec4 100644
--- a/src/cli/hook.ts
+++ b/src/cli/hook.ts
@@ -83,6 +83,10 @@ export function sessionStartContext(raw: string, deps: HookDeps = {}): string {
       const short = x.sessionId.slice(0, 8);
       lines.push(`- "${x.name ?? short}" (session ${short}) — resume: \`agentctl resume ${short}\``);
     }
+    lines.push(
+      'This list is a snapshot from when this session started; reminders get cleared from other sessions.' +
+      ' Before mentioning any of them again later, run `agentctl annotations --due` and mention only what it still lists.',
+    );
   }
 
   lines.push(
diff --git a/tests/cli/hook.test.ts b/tests/cli/hook.test.ts
index 6b6f96e..fc06f54 100644
--- a/tests/cli/hook.test.ts
+++ b/tests/cli/hook.test.ts
@@ -53,6 +53,7 @@ describe('sessionStartContext', () => {
     expect(out).toContain('1 other session(s)');
     expect(out).toContain('the other one');
     expect(out).toContain('`agentctl resume bbbb`');
+    expect(out).toContain('agentctl annotations --due');
   });
 
   it('always ends with the tool list so the model knows the commands', () => {