Bug Description

When OpenClaw Gateway restarts (e.g., after system reboot), the configuration file ~/.openclaw/openclaw.json is being overwritten with a nearly empty file, causing complete loss of configuration.

Environment

• OS: Linux (Ubuntu/Debian based)
• Node: 24.x
• OpenClaw: v2026.3.7

Reproduction Steps

1. Have a working OpenClaw configuration with ~470 lines (~11KB)
2. Restart the system or restart OpenClaw Gateway
3. After Gateway starts, check ~/.openclaw/openclaw.json
4. The file is reduced to ~10 lines (~400 bytes)
5. Gateway fails to start with error: Gateway start blocked: set gateway.mode=local (current: unset)

Actual Behavior

The configuration file is completely wiped on Gateway restart. The audit log shows config size dropped from 11653 bytes to 421 bytes, with 28 configuration paths lost.

Impact

• Severity: Critical (P0)
• Gateway becomes non-functional after restart
• All configuration including channel credentials, API keys, cron jobs, agent settings are lost

Suggested Fix

1. Add config integrity check before Gateway starts (verify key fields exist)
2. Add pre-write backup (backup before any config modification)
3. Add config operation logging (log read/merge/validate operations, not just write)
4. Add config size change alert (>20% change should trigger warning)