Definition
Plain language
A fake but realistic copy of a website or app used to safely train AI agents.
As stated in the literature
A self-contained, instrumented single-page web application that mimics real production software for RL training; in CUA-Gym, 94 such mocks span Slack-, Jira-, EHR- and similar app categories.
Also called: mock environments, mock app
Why it matters: Realistic but safe replicas let agents train and be evaluated at scale without leaking data or breaking production systems.
For example, a Slack-style mock app lets an agent practice sending messages, creating channels, and reacting to threads without touching real users.