fix(copilot): stop async chat auto-titling from clobbering an explicit rename

[waleedlatif1]

Summary

Chat title generation is fired at turn start and resolves asynchronously, but its write was unconditional:

await db.update(copilotChats).set({ title }).where(eq(copilotChats.id, chatId))

The guard that decides whether to generate a title (if (!chatId || currentChat?.title || !isNewChat) return) evaluates a snapshot taken at request start. The write then happens much later with no re-check — a classic check-then-write (TOCTOU) race. If a user renames the chat while the title is being generated, the generated title lands afterward and silently overwrites the rename.

This is reachable in normal use: rename a chat shortly after sending the first message and the rename can disappear.

Fix

Make the write conditional on the title still being unset, so a generated title can only ever fill an empty slot:

.where(and(eq(copilotChats.id, chatId), isNull(copilotChats.title)))

copilotChats.title is nullable with no default, so isNull is exactly the "no title yet" state. The update is atomic, so the explicit rename deterministically wins. When the write loses the race (0 rows), the follow-up title notification is skipped as well — we should not announce a title the row no longer holds.

Both auto-title call sites are fixed, since they had the identical unconditional write:

• lib/copilot/request/lifecycle/start.ts — the interactive turn path
• lib/mothership/inbox/executor.ts — the inbox task path

Why not "eliminate the race" instead

The concurrency is inherent — an async background title generator runs alongside user actions, and awaiting it would block the turn on a title LLM call. The race cannot be removed, only made well-defined; a conditional (compare-and-set) update is the standard way to do that, and it makes the outcome deterministic: an explicit title always wins, a generated one only fills a gap.

Testing

tsc --noEmit and biome clean. Existing unit tests for both changed paths pass (start.test.ts, executor.test.ts — 13 tests). This also removes the root cause of a flaky integration check that asserted a forked chat inherits its parent's renamed title.

Type of change

• Bug fix (non-breaking)

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1 Skipped Deployment

Project	Deployment	Actions	Updated
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[waleedlatif1]

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[cubic-dev-ai]

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[greptile-apps]

Greptile Summary

This PR prevents asynchronous auto-title generation from overwriting an explicit chat rename by making both title writes conditional on the title remaining null. It also suppresses title notifications when the conditional update loses the race.

• Adds atomic null-title checks to interactive-turn and inbox-task title generation.
• Uses returned affected rows to determine whether a title notification should be published.

Confidence Score: 5/5

The PR appears safe to merge, with both asynchronous title paths correctly preserving explicit renames.

The conditional PostgreSQL updates atomically write only to null titles, and the returned-row checks prevent publishing a generated title when a concurrent rename has already won.

Important Files Changed

Filename	Overview
apps/sim/lib/copilot/request/lifecycle/start.ts	Makes interactive auto-title persistence conditional and publishes the generated title only when the database update succeeds.
apps/sim/lib/mothership/inbox/executor.ts	Applies the same atomic title-write and notification behavior to inbox task execution.

Sequence Diagram

sequenceDiagram
  participant Generator as Async title generator
  participant DB as Chat database
  participant User as User rename
  participant Events as Title events
  Generator->>Generator: Begin generating title
  User->>DB: Set explicit title
  Generator->>DB: Update title where title IS NULL
  DB-->>Generator: No affected rows
  Generator-->>Events: Skip generated-title notification

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[cubic-dev-ai]

No issues found across 2 files

Confidence score: 5/5

• Automated review surfaced no issues in the provided summaries.
• No files require special attention.

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