Problem

When a WhatsApp Web 503 disconnect occurs while the agent is sending a reply, the message gets truncated mid-stream. The user receives a partial message with no indication it was cut off.

Observed behavior:

• Agent starts sending a multi-paragraph response
• WhatsApp Web connection drops (503 Service Unavailable)
• Gateway reconnects automatically (~3 seconds)
• User receives only partial message (e.g., just the bullet points from the middle of the response)

Log evidence:

status=503 Service Unavailable Stream Errored (unknown)
WhatsApp Web connection closed (status 503). Retry 1/12 in 2.14s…

Expected Behavior

• Messages should either be delivered completely or not at all
• If a message fails mid-send, it should be re-queued after reconnection

Suggested Solutions

1. Delivery confirmation - Wait for WhatsApp delivery ACK before marking message as sent
2. Pending message buffer - Queue outbound messages and retry on reconnection failure
3. Atomic send - Don't stream partial content; buffer full response before sending

Environment

• Clawdbot version: npm package (latest)
• WhatsApp Web via Baileys
• Ubuntu/Linux VPS