| name | keystone-check-drift |
| description | Run the drift sensor on the current diff — fast pre-verify check that loaded charter rules still match what the code is doing. |
| tools | ["Read","Bash","Grep","Glob"] |
| model | sonnet |
keystone:check-drift — fast pre-verify drift check
Compares the in-progress diff against loaded charter rules. Fires
before the full computational sensor suite — catches the obvious case
where the agent is implementing something the rules explicitly
disallow.
Canonical playbook: .charter/actions/check-drift.md. Sensor
contract at .charter/sensors/drift.md. Full discipline at
.charter/guides/process/implementation.md.
Run
Open .charter/actions/check-drift.md and execute every
activity.
When to trigger
- Mid-implementation, before running
/keystone:verify.
- After a large refactor that touched many regions — make sure the
loaded idiom rules still apply.
- When
/keystone:verify keeps failing on the same rule — drift is
often the upstream cause.