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The LLM Eval Rubric Generator
Generate a set of automatic pass/fail eval checks for any prompt — schema-match, contains, regex, length, and is-valid-json — so a bad prompt edit or a silent model regression gets caught before your customers do.
# The LLM Eval Rubric Generator — a free tool by VernaOne (https://verna.one)
# Paste this whole prompt into ChatGPT, Claude, or Gemini, then describe your prompt/task at the bottom.
You are a QA engineer for LLM systems. For the prompt or task described at the bottom, write an **eval rubric**: a set of automatic, machine-checkable pass/fail checks that grade any output of that prompt.
Rules for the rubric:
- Prefer machine-checkable check types only: `is-valid-json`, `schema-match`, `contains`, `not-contains`, `regex`, `length`, `equals`, `one-of`.
- Each check must be specific enough that code could decide pass/fail with no human judgment.
- Cover three layers: (a) **format** — is the output shaped correctly; (b) **content** — does it contain / avoid the right things; (c) **safety** — refusal and guardrail behavior.
- 5–8 checks total. No vague or subjective checks ("is it good?"). If a subjective quality matters, convert it into a concrete proxy (e.g., "contains a numbered list of 3–5 items" → length + regex).
Output exactly this, and nothing else:
## Eval rubric
A table, one row per check:
| # | Check type | Target (field / whole output) | Condition | Why it matters |
## Machine-readable rules
The same checks as a JSON array, each: `{ "type": "...", "target": "...", "condition": "...", "severity": "error" | "warning" }`. `error` = must pass; `warning` = should pass.
## Edge cases to add later
2–4 tricky inputs worth adding as fixtures (e.g., empty input, very long input, adversarial input), one line each.
Rules:
- If the task doesn't specify an output format, assume the most likely one and note the assumption in one line before the rubric — do not ask me questions.
- Keep it tight. No filler.
---
DESCRIBE THE PROMPT / TASK TO EVALUATE (and paste an example output if you have one):
{{DESCRIBE YOUR PROMPT OR TASK HERE}}
↑ The header line (with the verna.one link) travels with the prompt when you share it.
How to use it
- Copy the prompt and paste it into ChatGPT, Claude, or Gemini.
- Describe your prompt or task at the bottom (paste an example output if you have one).
- Get a rubric of machine-checkable checks, plus a JSON version and edge cases to test.
- Attach the checks to your prompt in VernaOne so they run on every execution.
Run it for real, not just once
VernaOne turns the result into a versioned, model-agnostic endpoint with automatic fallback across every provider — call one name, change models without changing code.
Try VernaOne free →Frequently asked
What is an LLM eval?
An eval is an automatic check that grades a model's output pass or fail against a rule — for example, that the output is valid JSON, matches a schema, contains a required phrase, follows a regex, or stays within a length. Running evals on every output catches regressions from a prompt edit or a model change before they reach customers.
What makes a good eval rubric?
Machine-checkable rules beat vague ones. Prefer schema-match, contains, regex, length, and is-valid-json over subjective judgments, and make each check specific enough that code can decide pass/fail with no human in the loop. This prompt generates exactly that kind of rubric for your task.
How do I run these checks on every call?
You attach them to the prompt so they run automatically. In VernaOne you add eval rules to a prompt version, and every execution is graded pass/fail with the result stored — so a bad prompt edit or a silent model regression is flagged instead of shipping. This free prompt gives you the rubric to attach.
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