Instruction Following Checker

Verify that LLM output follows each instruction in your prompt.

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A long prompt can carry a dozen instructions — must include a disclaimer, never mention competitors, keep it under 100 words, always end with a CTA. Models miss some of these surprisingly often. This checker extracts the instructions from your prompt and audits the output against each, so you can see compliance at a glance instead of re-reading both texts line by line.

How it works

The tool splits your prompt into sentences and flags any that contain imperative cue words — must, should, do not, never, always, only — plus explicit length or format constraints. Each becomes a checklist item. For instructions it can verify mechanically (a banned word, a required phrase, a word limit) it runs the check against your output and shows a verdict with the reason. Instructions it cannot judge automatically are still listed so your checklist stays complete. Everything runs locally in your browser.

What it can and cannot verify

  • Auto-checkable: negative constraints (“do not mention X”), positive requirements (“must include Y”), and numeric limits (“under 100 words”).
  • Manual only: subjective or stylistic instructions (“be concise”, “sound friendly”) — surfaced for you to judge.

Tips

  • Write prompt instructions as clear, separate sentences so the extractor catches each one.
  • Treat every verdict as a prompt to look, not a final ruling — heuristics produce both false positives and false negatives.
  • Re-run after editing the prompt to confirm new constraints were actually picked up.
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