Q19 of 21 · AI for testing
What is the difference between AI-assisted testing and agentic/autonomous testing, and how do you decide which to adopt?
Short answer
Short answer: AI-assisted testing uses AI to help engineers write and maintain deterministic scripts. Agentic testing replaces the script with an AI that drives the browser or API autonomously at test runtime. They solve different problems with very different cost, speed, and reliability profiles.
Detail
AI-assisted testing (current mainstream): AI tools in the developer loop — generating test code, reviewing PRs, triaging failures. The output is a deterministic, human-reviewed artefact that runs reliably in CI. The AI accelerates human work; the human owns the result.
Agentic testing (emerging): an AI agent runs the test autonomously at test time — planning, clicking, asserting — without a pre-written script. There is no fixed artefact to review; the agent decides what to do based on the current page state.
Decision criteria for agentic adoption: Change frequency: if the UI changes every sprint and maintaining scripts costs more than agent runs cost, agentic may be cost-effective. Determinism requirement: if the test must produce the same result every run (payment flow, compliance check), use a scripted test. Agentic is non-deterministic by design. Speed and cost: agentic tests are 5–30× slower and cost per LLM call. Not suitable for fast PR pipelines. Purpose: agentic excels at exploration and broad coverage sweeps; scripted tests are better for regression of known critical paths.