deleting a conversation forgets what the platform stored about it

Found by a sanity check after two commanders were deleted through the UI: the Command HQ tables cascaded
perfectly and four OTHER tables kept a row each, for ever. 24 orphaned rows in chat_session_models, 26 in
chat_session_events, against 14 live transcripts.

Nothing cascades because there is nothing to cascade FROM. All four are keyed on a transcript id, and a
transcript is a file the harness writes — there is no row for a conversation, so the database cannot help and
the delete path has to be explicit. It was not.

Three of the four are inert: a model, a bell preference, a durable copy of turn output nothing will ask for
again. `nudges` is not — it is a SCHEDULE, read by the tick in nudger.ts. A nudge belonging to a deleted
conversation is a timer that keeps firing at something that no longer exists. That is what turned this from
untidy into worth doing now.

deleteClaudeSession returns the IDS it removed rather than a boolean, because a `/clear` chain is several
transcripts presenting as one conversation and forgetting the head while orphaning its parts is the same bug
at a smaller scale.

THE TRAP THAT CHANGE INTRODUCED, caught before shipping: every call site said `if (deleteClaudeSession(...))`
and an empty array is TRUTHY in JavaScript, so a delete that found nothing would have reported success. The
typecheck was clean — `string[]` is a perfectly good truthy expression. All three sites test `.length` now.
Fifth silently-wrong thing today that a typecheck could not see.

Cleared the existing orphans with the same function the delete path now uses, after checking the one thing
that would have made it wrong: whether any of them belonged to a member, whose transcripts live in a home
this scan does not read. There is one account on this machine, so they were all the owner's.

Two chat_session_events rows appeared again immediately after, and are not a leak: the durable log is written
independently of the transcript — that is what makes turn output survive officer being down — so a session
that has just begun legitimately has events before a transcript exists.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/databases/officer_db/src/chat-session-cleanup.ts

@@ -0,0 +1,42 @@
+import { inArray } from 'drizzle-orm';
+import { db } from './db';
+import { chatSessionEvents } from './chat-events/schema';
+import { chatNotificationPrefs } from './chat-notification-prefs/schema';
+import { chatSessionModels } from './chat-session-models/schema';
+import { nudges } from './nudges/schema';
+
+/*
+  Everything the platform stores ABOUT a conversation, forgotten together.
+
+  ── Why this exists as one function ──
+
+  Four tables are keyed on a transcript id and none of them has a foreign key to anything, because the thing
+  they describe is a FILE — a transcript on disk, written by the harness. There is no row for a chat session
+  to reference, so the database cannot cascade and the delete path has to be explicit.
+
+  It was not. Deleting a conversation removed the transcript and left all four behind, for ever. Found on
+  2026-08-22 by counting rows after two commanders were deleted through the UI: `chat_session_models` held 36
+  rows against far fewer live conversations.
+
+  ── Why it is more than untidy ──
+
+  Three of the four are inert — a model, a bell preference, a durable copy of turn output that nothing will
+  ask for again. `nudges` is not: it is a SCHEDULE, and the tick in `nudger.ts` reads it. A nudge left behind
+  by a deleted conversation is a timer that keeps firing at something that does not exist.
+
+  ── Why it takes a list ──
+
+  A `/clear` chain is several transcripts presenting as one conversation, and deleting it deletes every part.
+  Forgetting one id and leaving its siblings is the same bug at a smaller scale, so the caller passes the ids
+  it actually removed.
+*/
+export async function forgetChatSessions(sessionIds: string[]): Promise<void> {
+  if (!sessionIds.length) return;
+  // Sequential rather than a transaction: these are independent tables with no invariant between them, and
+  // a partial forget is strictly better than a failed delete that leaves the transcript gone and every row
+  // in place. Each is idempotent — running it twice removes nothing the second time.
+  await db.delete(nudges).where(inArray(nudges.sessionId, sessionIds));
+  await db.delete(chatSessionModels).where(inArray(chatSessionModels.sessionId, sessionIds));
+  await db.delete(chatNotificationPrefs).where(inArray(chatNotificationPrefs.sessionId, sessionIds));
+  await db.delete(chatSessionEvents).where(inArray(chatSessionEvents.sessionId, sessionIds));
+}

src/databases/officer_db/src/index.ts

@@ -39,6 +39,7 @@ export * from './nudges';
 export * from './ai-provider-usage';
 export * from './anthropic-accounts';
 export * from './theme-favorites';
+export { forgetChatSessions } from './chat-session-cleanup';
 export * from './command-hq';
 export * from './dashboards';
 export * from './integrations';