The RAG question nobody plans for: 'what if it's just not in the documents?'

A confidence gate catches weak matches, but out-of-scope questions need a different check: does the retrieved context even address the question's topic at all?

Pranjul Rathour
Pranjul Rathour

A confidence gate on retrieval scores catches weak matches. It does not catch a strong match on the wrong topic — a question about refund policy retrieving a strongly-matched but irrelevant passage about return shipping addresses.

Add a relevance check, separate from a similarity score

After retrieval, ask the model directly: 'does this context address this question, yes or no?' before generating the final answer. It is a cheap extra call that catches a class of errors similarity scores miss entirely.

  • Refuse clearly when the check says no — 'I don't have that in the documents I was given' beats a confident wrong guess.
  • Log refusals; a spike on one topic usually means a document gap, not a bug.
  • Do not skip this check to save latency on a support or compliance bot — the cost of a wrong answer is higher there.

Builds on what a confidence gate is and citations in RAG answers.

RAGGuardrailsUX
Pranjul Rathour
Pranjul Rathour
GenAI Engineer · Kanpur, Uttar Pradesh, India

GenAI engineer and AI product builder with 2+ years shipping production-grade AI systems: RAG pipelines, fine-tuned LLMs, hybrid retrieval and multi-modal apps across vision, speech and OCR, architected end to end from ingestion to deployment. Leads engineering for SCULT INDIA's 14-member team, founded the 500+ member TechVerse Enclave community and has mentored 200+ students. Three hackathon first prizes: Changethon 2025 (IIT Roorkee), Product Genesis at Vividhotsava 2025 (CSJMU Kanpur) and BYTEBATTLE (MeetKats).

Open to GenAI roles, hackathon judging, mentorship sessions and guest talks at colleges. Email pranjulrathour41@gmail.com.

Keep reading

More on RAG & retrieval

All RAG & retrieval posts →
Campus talks · hackathon judging · mentoring

Want this as a live session at your college?

Open to GenAI roles, hackathon judging, mentorship sessions and guest talks at colleges.

Pranjul Rathour, GenAI engineer in Kanpur