Your AI coding agent evaluation is only as good as its sandbox

A passing agent evaluation can prove the wrong thing. The answer might be correct while the measurement behind it is invalid. An AI coding agent can generate an answer from internal knowledge and related patterns. But it can also adapt information from the prompt or retrieve evidence from its environment. Each route demonstrates a different capability, yet the final answer rarely reveals which route the agent took. If your evaluation is meant to determine what a model knows, then the sandbox must prevent the agent from retrieving the knowledge under test. Otherwise, the score represents everything available to the agent during the run. It can look impressive while answering a different question. Before restricting a single tool,…