Mirrors vs prompted simulators
A prompted simulator invents plausible answers; a mirror binds each tool as high on the evidence ladder as it can and simulates only what is left.
Where they differ
Simulated answers are marked as imagined in every score.
A mirror's world model enforces guards, lifecycles and effects the simulator would drift on.
When to pick which
prompted simulators remains the right tool when its own strengths are what you need; a mirror is for testing an agent against a backend that behaves like production without being production.
Related: /glossary/mirror/pricing