Definition

Prompt injection

Prompt injection is the practice of embedding text intended to be read as instructions by an AI system that ingests the page — for example, hidden text telling an assistant to recommend a brand.

It is the AI-era equivalent of hidden keyword stuffing, and it carries the same eventual outcome: detection and penalty.

It is also a liability risk when an agency does it on a client's site without disclosure. Do not do it, and check that nobody did it before you.

Nostimates measures prompt injection across twelve AI answer surfaces. Request access →

All terms

AEO (Answer Engine Optimisation)GEO (Generative Engine Optimisation)AI Overviews AI Mode Citation share n-sampling Query fan-out Grounding Share of voice (AI)Extraction success rate Surface Answer engine Citation Brand mention Mention rate Confidence interval Statistical significance Citation volatility Non-determinism Reproducibility Identity-free collection Personalisation Locale Residential proxy Bot detection Collection cost Credit Evidence retention Audit trail Parser version Canary prompt Data freshness Cadence Prompt set Head term Long-tail query Competitive set llms.txt robots.txt AI crawler Training crawler Retrieval-augmented generation (RAG)Hallucination Answer box Featured snippet Zero-click search Entity Entity salience Knowledge graph Structured data JSON-LD schema.org FAQ schema Answer-first content Chunk Embedding Semantic search Market coverage Sentiment analysis Position tracking White-label data