Why AI Hallucinates: How Bad Input Causes Bad Answers
How noisy, incomplete or contradictory input leads to AI hallucinations, and simple preprocessing steps that reduce them.
Garbage in, confident garbage out
When text is scrambled, truncated or missing, models fill gaps with plausible guesses. A table extracted out of order or a document cut off by the context limit invites invention.
Reduce the risk
Practical steps:
- Extract cleanly with PDF to Clean Text
- Confirm everything fits with the Token Counter
- Remove distracting noise with the Context Compressor
- Ask for quotes supporting each claim
Ask for grounding
Instruct: 'Answer only from the document. If the answer is not there, say so.' Combined with clean input, this sharply reduces made-up details.
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- PDF to Clean Text — Strips headers, footers, page numbers, and hyphenation. Outputs TXT or Markdown.
- Context Compressor — Reduce token usage with compression strategies tuned for LLMs.
- Token Counter — Live token, character, and context-window meter for any prompt. Uses official tiktoken encoders.
Tools mentioned
Frequently asked
Can clean input eliminate hallucinations?
No, but it reduces them significantly by making correct information easy to find.
What prompt helps?
Ask the model to answer only from the provided text and say when information is missing.
Keep reading
How to Prepare PDFs for ChatGPT, Claude, and Gemini
A practical guide to extracting clean, AI-ready text from PDFs — born-digital and scanned — so ChatGPT, Claude, and Gemini answer accurately and don't waste tokens on headers, footers, and page numbers.
The Best Way to Feed Long Documents to Claude (and Other Long-Context Models)
Claude's 200K-token context is generous, but you'll still want to clean, compress, and structure long documents before sending them. Here's a step-by-step playbook.
Cleaning Whisper Transcripts for AI Summaries
OpenAI Whisper, Otter, and YouTube transcripts are full of timestamps, filler words, and speaker noise. Here's how to strip them before sending to ChatGPT or Claude — and why it matters.