Bug Description

Cron jobs configured with "delivery": {"mode": "announce"} are sending duplicate messages to the configured channel. Each cron execution results in 2 identical messages being delivered.

Steps to Reproduce

1. Create a cron job with announce delivery:

openclaw cron add --name test_cron --cron "0 * * * *" --message "test" --deliver

2. Wait for cron to execute
3. Observe 2 identical messages in the target channel

Expected Behavior

One message should be sent per cron execution.

Actual Behavior

Two identical messages are sent for each cron execution.

Environment

• OpenClaw version: 2026.2.25
• Platform: Linux
• Channel: Telegram

Additional Notes

• Jobs with "mode": "none" do not have this issue
• The issue appears to be in the announce delivery path
• Log shows cron executes once but message tool is called twice