TL;DR: A leaked system prompt for Claude 3.7 Sonnet reveals exactly how ChatAI interfaces like Claude and ChatGPT browse, summarize, and present web content. For SEOs, this is your sneak peek into how ChatAI responses are formed, what types of content make the cut, and what it takes to get mentioned. With Google’s full rollout of AI Mode to all US users (non-logged-in!) as of May 20, 2025, this insight could be game-changing.
Why This Leak Matters for SEOs
As Google expands with AI Mode, ChatGPT and Perplexity becomign more popular, organic links are getting pushed further down the page or lose relevance. This new world demands a new SEO strategy: ChatAI optimization. Understanding how language models decide what to show users is now just as critical as classic keyword targeting.
The Claude system prompt leak gives us an unprecedented behind-the-scenes look at how one of the leading LLMs performs live web searches and presents results. Here are the most important takeaways for SEO practitioners.
Key Insights From the Claude 3.7 Leak
1. Citation System Is Sentence-Based
Claude wraps every specific claim with <antml:cite> tags. These tags reference exactly which sentences in a document support each claim. The system rewards concise, clearly supported statements, not vague rambling.
SEO takeaway: Break information into short, verifiable claims. Bullet points, summaries, and mini-facts will be more likely to be quoted or referenced.
2. Prioritization of Original Sources
“Prioritize original sources (company blogs, peer-reviewed papers, gov sites, SEC) over aggregators.”
This is huge. Claude actively prefers to cite your original content over third-party summaries or listicles.
SEO takeaway: Host original research, reports, or insights. First-party content wins.
3. Search Query Behavior Is Programmatic
Claude auto-generates search queries like semiconductor export restrictions 2025, but avoids site: or "-keyword" syntax. It focuses on short, keyword-like queries—almost like a traditional user—but evaluates multiple versions to refine results.
SEO takeaway: Think like a bot. Use natural, unquoted headings. Avoid keyword stuffing. Structure your articles with atomic, independent sections.
4. Summarization Style Avoids Copyright Risk
Claude won’t summarize paragraphs verbatim. It’s trained to produce substantially shorter, transformed summaries. Only one quote per source is used, and it must be under 20 words.
SEO takeaway: If you want to be cited, write short quotable gems. Zingers win. Consider adding a TL;DR section.
5. No Repetition, No Fluff
Claude explicitly avoids repeated phrases in a session and penalizes itself for being verbose. This suggests it cherry-picks variety-rich content with tightly packed information.
SEO takeaway: Stop bloating your articles. Cut filler. A ChatAI won’t choose the 2,000-word monologue.
New SEO Rules for ChatAI Era
| Old SEO | New ChatAI SEO |
|---|---|
| Keyword usage | Sentence clarity |
| Backlinks | Source originality |
| Long-form dominance | Snackable atomic facts |
| Meta title focus | Clean headings + mini-summaries |
| PageRank | Structured citations & snippet quotability |
Google Just Rolled Out AI Overviews to All US Users
As of May 20, 2025, Google announced at I/O that AI Mode is now shown to all non-logged-in users in the U.S. This means a vast amount of organic traffic will flow through AI-generated summaries. And Claude is not far behind in its capabilities.
This system prompt leak gives SEOs the blueprint for optimizing not just for Google, but for AI interpreters that control what users actually see in the new SERP reality.
Final Word
This isn’t just a leak. It’s a cheat sheet for the future of SEO.
As ChatAI search interfaces become the default mode of information retrieval, knowing how to appear in a summary box is the new Page 1.
Thanks to Asgeirtj for publishing the leaked system prompt that allowed this analysis!
