diff --git a/src/databases/officer_db/src/chat-session-cleanup.test.ts b/src/databases/officer_db/src/chat-session-cleanup.test.ts
new file mode 100644
index 00000000..b85cc6bf
--- /dev/null
+++ b/src/databases/officer_db/src/chat-session-cleanup.test.ts
@@ -0,0 +1,97 @@
+import { afterEach, describe, expect, test } from 'bun:test';
+import { inArray } from 'drizzle-orm';
+import { db } from './db';
+import { chatSessionEvents } from './chat-events/schema';
+import { chatSessionModels } from './chat-session-models/schema';
+import { forgetChatSessions } from './chat-session-cleanup';
+
+/*
+  Deleting a conversation, across the two id spaces it actually spans.
+
+  This file touches the real database, which the rest of the suite avoids on purpose. It has to: the defect
+  it exists to catch was never in a decision, it was in which column a `delete` matched. A test built on a
+  fake store would have passed against both the broken version and the fixed one.
+
+  Safe because every id here is a synthetic uuid in a reserved block that no harness produces, and because
+  each test removes exactly what it wrote. Nothing reads live rows and nothing deletes by anything but these
+  ids.
+
+  Two regressions are pinned here, and they are the same bug seen twice:
+
+  1. `chat_session_events` is keyed on officer's SESSION KEY while everything else is keyed on the TRANSCRIPT
+     id. One list passed to all four tables matched nothing in this one, ever, by construction — and counting
+     events by transcript id to check also returns zero by construction, so it read as clean.
+  2. Resolving that key from a live in-memory map only works for a session younger than the process. After a
+     restart it comes back null, the key list arrives empty, and the events survive a delete that reports
+     success. The key has to come from the rows, which carry `claudeSessionId` in their payload.
+*/
+
+const TRANSCRIPT = '00000000-dead-4000-8000-000000000001';
+const SESSION_KEY = '00000000-dead-4000-8000-0000000000ff';
+
+afterEach(async () => {
+  await db.delete(chatSessionEvents).where(inArray(chatSessionEvents.sessionId, [SESSION_KEY]));
+  await db.delete(chatSessionModels).where(inArray(chatSessionModels.sessionId, [TRANSCRIPT]));
+});
+
+const countEvents = async () =>
+  (
+    await db
+      .select()
+      .from(chatSessionEvents)
+      .where(inArray(chatSessionEvents.sessionId, [SESSION_KEY]))
+  ).length;
+
+describe('forgetChatSessions', () => {
+  test('removes events keyed on the session key, found via the transcript id in their payload', async () => {
+    // Exactly the real shape: one `result` carries both ids, the rest carry neither.
+    await db.insert(chatSessionEvents).values([
+      { sessionId: SESSION_KEY, event: { type: 'result', sessionId: SESSION_KEY, claudeSessionId: TRANSCRIPT } },
+      { sessionId: SESSION_KEY, event: { type: 'assistant:text', text: 'no ids on this one' } },
+      { sessionId: SESSION_KEY, event: { type: 'tool:start', toolName: 'Bash' } },
+    ]);
+    expect(await countEvents()).toBe(3);
+
+    // No `sessionKeys` — this is the post-restart case, where the caller cannot resolve one.
+    await forgetChatSessions({ transcriptIds: [TRANSCRIPT] });
+
+    // All three, not just the one carrying the id: resolving the key covers the whole session.
+    expect(await countEvents()).toBe(0);
+  });
+
+  test('an explicit session key still works when no event names the transcript', async () => {
+    await db
+      .insert(chatSessionEvents)
+      .values([{ sessionId: SESSION_KEY, event: { type: 'assistant:text', text: 'nothing identifying here' } }]);
+
+    await forgetChatSessions({ transcriptIds: [TRANSCRIPT], sessionKeys: [SESSION_KEY] });
+    expect(await countEvents()).toBe(0);
+  });
+
+  test('leaves another session alone', async () => {
+    const OTHER = '00000000-dead-4000-8000-0000000000ee';
+    await db
+      .insert(chatSessionEvents)
+      .values([{ sessionId: OTHER, event: { type: 'assistant:text', text: 'theirs' } }]);
+    try {
+      await forgetChatSessions({ transcriptIds: [TRANSCRIPT], sessionKeys: [SESSION_KEY] });
+      const left = await db
+        .select()
+        .from(chatSessionEvents)
+        .where(inArray(chatSessionEvents.sessionId, [OTHER]));
+      expect(left.length).toBe(1);
+    } finally {
+      await db.delete(chatSessionEvents).where(inArray(chatSessionEvents.sessionId, [OTHER]));
+    }
+  });
+
+  test('forgets the transcript-keyed tables too', async () => {
+    await db.insert(chatSessionModels).values({ sessionId: TRANSCRIPT, model: 'claude-code/opus', planMode: false });
+    await forgetChatSessions({ transcriptIds: [TRANSCRIPT] });
+    const left = await db
+      .select()
+      .from(chatSessionModels)
+      .where(inArray(chatSessionModels.sessionId, [TRANSCRIPT]));
+    expect(left.length).toBe(0);
+  });
+});