AIChatAgent cleanup is per-DO and only triggered on local stream completion, which can leave cf_ai_chat_stream_* rows indefinitely for inactive DO instances

[Jerrynh770]

Hi Cloudflare Agents team,

First of all, thank you for @cloudflare/agents and @cloudflare/ai-chat — they’ve been really helpful for building resumable streaming on Workers.

I am using AIChatAgent with a common pattern: one Durable Object instance per chat (e.g. DO name = chatId). While reviewing storage growth, I noticed the built-in cleanup logic runs inside _completeStream() via _maybeCleanupOldStreams().

From the current implementation, cleanup is:

• Triggered only when a stream completes in the same DO instance
• Throttled by CLEANUP_INTERVAL_MS (10 minutes)
• Deletes only status = 'completed' streams older than CLEANUP_AGE_THRESHOLD_MS (24 hours)
• Targets cf_ai_chat_stream_chunks and cf_ai_chat_stream_metadata

This seems to imply the following behavior:
If a given DO instance (chatId) becomes inactive after a single conversation (i.e. no more stream completions happen in that DO), then its SQLite tables (cf_ai_chat_stream_chunks, cf_ai_chat_stream_metadata) may never be cleaned up, because _maybeCleanupOldStreams() will not be called again for that DO.

In our app, we persist final messages to Postgres as the source of truth, so we don’t need the DO to retain completed stream chunks long-term. We currently override _completeStream() to delete that stream’s chunks/metadata immediately to keep DO storage bounded, but we’re not sure if that’s the recommended approach.

Questions / request for guidance:

1. Is this “cleanup only on local completion” behavior intended / expected?
2. Are there recommended best practices for bounding DO storage in this pattern (one DO per chat)?
3. Would you consider supporting one of the following:
   • A public method/API to trigger cleanup explicitly (useful for cron/admin jobs)
   • A configurable retention policy / TTL for completed streams (e.g. minutes instead of 24h)
   • An option to eagerly delete completed stream chunks when the app persists messages elsewhere