The agent and safety evaluation framework from UK AISI
Inspect AI is an open-source framework from the UK AI Safety Institute, designed for evaluating LLM agents and safety properties. It is the framework most safety-focused organizations adopt because it is built around tasks that include tool use, multi-step reasoning, and adversarial scenarios.
What it does well
- Agent evaluation — supports tool use, sandbox environments, and stateful task completion.
- Safety evaluation — built-in patterns for capability assessment, dangerous-capability evals, and red-teaming.
- Reproducibility — every eval run is fully scripted and re-runnable.
- Multi-modal — supports text, image, and tool outputs.
- Provider-agnostic — OpenAI, Anthropic, Google, local models.
Where it shines
If you are evaluating an agent that uses tools, browses, executes code, or plans across multiple steps, Inspect AI is built for that workload. Other frameworks bolt agent support on top; Inspect AI assumes it.
Where it doesn't fit
For simple prompt-and-response evals, the framework is overkill. promptfoo or DeepEval are lighter for that use case.
Principle: If your eval involves tool use, code execution, or multi-step planning, reach for Inspect AI. If it's prompt-and-response, reach for something lighter.