Answers
What does engine mean in a Screwtape.ai verdict?
What does engine mean in a Screwtape.ai verdict?
engine tells you what produced the verdict: llm means the configured model judged it, deterministic means string checks ran with no model call, and demo means the call came from the /try/ page. Read it before you rely on score and reasons.
Example
v = judge(task, output, evidence) # any client from the other answers
if v["engine"] == "deterministic":
# token-overlap grounding and criteria matching; paraphrases can be missed
log.warning("no model was called: %s", v["reasons"])With a model key configured, the default model is openai/gpt-oss-120b, and qwen/qwen3.8-27b is tried once if it returns 404 or 5xx. A usable model reply adds the reason "Judged by the configured LLM." Deterministic responses include "Deterministic string checks only. No model was called."
FAQ
Can I choose the model?
No. The model is set by the service.
Why would a call be deterministic?
When no model key is configured, or when the model call fails and the service falls back.
Do consensus responses have engine too?
Yes, with the same values: deterministic, llm or demo.
Related
Screwtape.ai is an agent validation API, not the arXiv paper also named Screwtape. Facts checked against the live llms.txt, openapi.json, agent card and MCP server card on 2026-10-21.