Content-Signal Directive
A robots.txt directive that lets publishers declare how their content may be used for AI search, training, and input.
The Content-Signal directive is an extension to robots.txt that lets website owners express granular preferences about how AI systems may use their content. Rather than a simple allow or disallow, it distinguishes between uses such as AI search, model training, and AI input, giving publishers more nuanced control.
For example, a publisher might permit their content to be used for AI search and grounding, so they remain citable in answer engines, while opting out of having it used to train future models. This addresses a common tension between wanting AI visibility and protecting content from uncompensated training use.
Because adoption is still emerging, support varies across AI companies. Including a clear Content-Signal declaration is a recommended part of a modern crawler-access audit, and tools like the AEO Vision AI Bot Detector surface whether a site has one configured.
Related Terms
AI Crawlers
Automated bots used by AI companies to discover and index web content for training data or retrieval-augmented generation.
GEO Audit
A structured assessment of how well a brand is optimized for generative engines, spanning technical, content, off-site, and Share of Model signals.
llms.txt
A proposed standard file (similar to robots.txt) that provides structured information about a website specifically for AI models and LLMs.
AEO Vision Content Team
Insights on AI search visibility, answer engine optimization, and brand discovery across ChatGPT, Perplexity, Gemini, Claude, and Google AI Mode.
Track your Content-Signal Directive performance
AEO Vision helps brands measure and improve their AI search visibility across every major platform.