--- title: "Content Signal Generator for robots.txt (ai-train)" description: "Free Content Signal generator. Pick search, ai-input and ai-train values and copy a robots.txt block. It runs in your browser and stores nothing." url: https://seenlens.com/tools/content-signal-generator last_updated: 2026-11-06 --- # Content Signal generator for robots.txt The Content Signal generator writes the robots.txt block that states whether your content may be used for search, AI input and AI training. It runs in your browser, so we fetch nothing and store nothing. This is a robots.txt tool, not an electronic signal generator. A Content Signal is a preference, and no crawler has to obey it. By SeenLens. Last updated: 2026-11-06 ## What does the generator write? The generator writes one `Content-Signal` line for robots.txt. The line has three signals, and each one takes the value yes or no: | Signal | Covers | | --- | --- | | `search` | Building a search index and returning results such as links and short excerpts. It excludes AI-generated search summaries. | | `ai-input` | Feeding content into AI models, for example retrieval augmented generation, grounding or other real-time use for AI search answers | | `ai-train` | Training or fine-tuning AI models | This output allows search, allows AI input and opts out of training: ```text User-agent: * Content-Signal: search=yes, ai-input=yes, ai-train=no Allow: / ``` Cloudflare, which published the policy on 24 September 2025, says a signal set to yes means go, a signal set to no means stop, and a missing signal has no meaning. A missing signal does not mean you have no preference. It means you did not state one in robots.txt. ## How do I use the generated block? 1. Set each signal in the form and copy the block. 2. Paste the `Content-Signal` line inside each `User-agent` group in your robots.txt. A line outside a group does not belong to a crawler. 3. Publish the file at `/robots.txt`. 4. Run the [AI crawler checker](https://seenlens.com/tools/ai-crawler-checker) on a page. It reads your `Content-Signal` lines. Keep your `Allow` and `Disallow` rules. A Content Signal does not replace them. ## What does a Content Signal not do? - **It does not enforce anything.** Cloudflare writes that signals express preferences and are not technical countermeasures against scraping. Some companies may ignore them. For enforcement, use firewall rules. - **It is not a finished standard.** The IETF AI Preferences (aipref) working group is developing a formal vocabulary on similar ideas, and names may still change. See the [guide to Content Signals](https://seenlens.com/guides/content-signals-robots-txt). - **It does not control Google Search.** Google's documentation for AI features does not mention Content Signals. Googlebot and `Google-Extended` follow their own robots.txt rules. - **It is not a legal contract.** Cloudflare's policy text states that the signals reserve rights under Article 4 of EU Directive 2019/790. Ask a lawyer how that applies to you. ## How do I fix a missing or wrong Content Signal? - [Add Content Signals to robots.txt](https://seenlens.com/fixes/add-content-signals): the fix for the scan check that finds no preference. - [robots.txt blocks AI crawlers](https://seenlens.com/fixes/robots-txt-blocks-ai-crawlers): a signal does not undo a `Disallow` rule. - [robots.txt is missing](https://seenlens.com/fixes/robots-txt-missing): create the file first. - [What are Content Signals?](https://seenlens.com/glossary/content-signals): the definition and the history. ## Frequently asked questions ### What does ai-train=no do? It states that you do not want your content used to train or fine-tune AI models. It is a request. A crawler that does not read Content Signals can still fetch the page. ### Do AI crawlers respect Content Signals? There is no complete list. Cloudflare says the signals are preferences and that some companies may ignore them. Check each operator's documentation. The [Content Signals guide](https://seenlens.com/guides/content-signals-robots-txt) tracks this. ### Does ai-train=no stop AI Overviews? No. Google's AI features page does not list Content Signals. It lists nosnippet, data-nosnippet, max-snippet and noindex as the controls that limit what Search shows. ### What does Cloudflare put in the managed robots.txt? Cloudflare serves `Content-Signal: search=yes, ai-train=no` for customers who turn on the managed robots.txt feature. It does not serve an ai-input signal, because it does not know those customers' preference. ### Should I set ai-input to yes? Set yes if you want AI search answers to use and cite your content. Set no if you do not. Search crawlers such as OAI-SearchBot decide inclusion in AI search, so read the [AI crawler guide](https://seenlens.com/guides/robots-txt-for-ai-crawlers) too. ## Related tools - [AI crawler checker](https://seenlens.com/tools/ai-crawler-checker): read your live robots.txt for 14 crawlers. - [llms.txt checker](https://seenlens.com/tools/llms-txt-checker): validate an llms.txt file. - [GEO audit](https://seenlens.com/tools/geo-audit): the Content-Signal check is one of 38. - [All tools](https://seenlens.com/tools). ## Method and sources The generator follows the syntax in Cloudflare's Content Signals Policy. The scan check `content-signal` looks for a `Content-Signal` line in robots.txt. Last reviewed 2026-11-06. ## Sources - [Cloudflare: Giving users choice with Cloudflare's new Content Signals Policy](https://blog.cloudflare.com/content-signals-policy/) (syntax, three signals, managed robots.txt, preference not enforcement, CC0 license, 24 September 2025, checked 2026-11-06) - [contentsignals.org](https://contentsignals.org/) (describes the IETF AI Preferences work, checked 2026-11-06) - [Google: AI features and your website](https://developers.google.com/search/docs/appearance/ai-features) (controls for AI features, checked 2026-11-06)