How a mirror compares with the other ways to test an agent.
Mirrors vs mirrord mirrord routes a local process into a live cluster; a mirror replaces the backend with a twin built from traces.
Mirrors vs hand-written mocks Mocks are written by people and go stale; a mirror is rebuilt from the traces the agent keeps producing.
Mirrors vs record and replay Replay returns the recorded answer to the recorded call; a mirror answers new calls from a world model.
Mirrors vs staging environments Staging is shared, slow to reset and expensive to keep close to production; a twin starts in seconds and is seeded per session.
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.
Mirrors vs contract tests Contract tests check shapes; a mirror checks behaviour across a whole conversation.