# Shadow mode In shadow mode AvertGate makes and records every decision but stops nothing. It lets you see what a new policy would do on live traffic with no risk. ## How to enable Any of the following enables shadow: - CLI: `avertgate start --shadow` (or `--dry-run`) - Environment variable: `SHADOW_MODE=true` or `AVERTGATE_SHADOW_MODE=true` - SDK: `shadowMode: true` - Policy: `mode: shadow` or `defaults.shadow_mode: true` - Per tool: `shadow_mode: true` ## Effect A call that would be blocked is recorded as SHADOW_BLOCK, one that would go to approval as SHADOW_ESCALATE, and the tool **runs**. In the dashboard you can filter these events to answer "what would we have blocked?". > **Careful**: There is no protection in shadow mode. Use it only for measurement and rollout; then switch to `enforce`.