Bug Description

When a reply contains markdown tables and is moderately long (~2000+ chars), the message sent to Telegram can be empty, resulting in:

[telegram] sendMessage failed: Call to 'sendMessage' failed! (400: Bad Request: message text is empty)
[telegram] final reply failed: GrammyError: Call to 'sendMessage' failed! (400: Bad Request: message text is empty)

Reproduction

1. Send a reply with markdown tables (using | for columns)
2. Reply should be ~2000+ characters
3. Message arrives empty to Telegram

Expected Behavior

Message should either:

• Render correctly (tables converted to text)
• Fall back to plain text if markdown fails
• Never send empty message

Environment

• OpenClaw version: 2026.1.30
• Channel: Telegram
• OS: Linux (Ubuntu on VPS)

Logs

2026-02-01T22:37:06.083Z [telegram] sendMessage failed: Call to 'sendMessage' failed! (400: Bad Request: message text is empty)

Workaround

Avoid markdown tables in Telegram replies; use bullet lists instead.