AI search is exploding. According to recent data, AI-referred traffic grew 527% in the first five months of 2025. ChatGPT, Claude, Perplexity, and Gemini are becoming primary research tools for millions of users.

If your website isn't optimized for AI search, you're invisible to a rapidly growing audience.

This guide covers everything we've learned building AgentDomainService—a site designed from day one for AI agents.

Why AI Search Optimization Matters

Traditional SEO focuses on Google rankings. But users increasingly ask AI assistants directly:

• "What's the best project management tool for startups?"
• "How do I check if a domain is available?"
• "Compare React vs Vue for a new project"

When an AI answers these questions, it cites sources. Those citations drive traffic. Sites that appear in AI responses see significant referral traffic from ChatGPT, Perplexity, and Claude.

The AI Search Landscape in 2025

Step 1: Create an llms.txt File

llms.txt is a proposed standard (similar to robots.txt) that helps AI agents understand your site. Over 600 websites have adopted it, including Anthropic, Stripe, Cloudflare, and Zapier.

Basic llms.txt Structure

Create a file at yoursite.com/llms.txt:

YourSite.com

Brief description of what your site does.

Quick Start

The most important action users can take:
  GET https://yoursite.com/api/main-endpoint

Key Pages

/docs - Documentation
/pricing - Pricing information
/blog - Latest articles

API Reference

Brief explanation of your main endpoints...

Advanced: llms-full.txt

Anthropic (Claude's creator) specifically requests llms-full.txt—a comprehensive version with complete documentation in a single file. This helps Claude deeply understand your service.

Step 2: Configure robots.txt for AI Crawlers

Allow AI search crawlers access to your site:

ChatGPT / OpenAI
User-agent: OAI-SearchBot
Allow: /

User-agent: ChatGPT-User
Allow: /

Claude / Anthropic
User-agent: Claude-SearchBot
Allow: /

User-agent: Claude-User
Allow: /

Perplexity
User-agent: PerplexityBot
Allow: /

User-agent: Perplexity-User
Allow: /

Google (including AI Overviews)
User-agent: Googlebot
Allow: /

User-agent: Google-Extended
Allow: /

Note: -User agents are user-initiated fetches (when someone asks the AI to visit your site). Bot agents are crawlers building the AI's knowledge base.

Step 3: Add JSON-LD Structured Data

Structured data helps AI search engines understand your content. Add JSON-LD to your pages:

Google's AI Overviews and Gemini frequently pull from structured data.

Step 4: Structure Content for AI Readability

AI models prefer content that's easy to parse:

Answer Questions Upfront

Bad:

In this article, we'll explore the various factors that contribute to domain availability checking, including historical context and market dynamics...

Good:

Is example.com available? No, example.com is registered. Here's how to check any domain instantly...

Put the answer in the first 2 lines. AI models extract this directly.

Use Clear Headings and Lists

AI models love:

• Q&A format — Question as heading, answer below
• Numbered steps — 1, 2, 3 instructions
• Tables — Structured comparisons
• TL;DR sections — Summary at top or bottom

Include Specific Data

Vague content gets ignored. Specific data gets cited:

• "Fast response times" → "Average response time: 47ms"
• "Affordable pricing" → "Free tier, then $9/month"
• "Many integrations" → "Integrates with Slack, GitHub, and 50+ tools"

Step 5: Server-Side Rendering (SSR)

This is crucial. AI browsing tools struggle with client-side rendered (CSR) apps.

When ChatGPT's browsing feature visits a React SPA, it often sees:

That's useless. The actual content loads via JavaScript, which AI crawlers may not execute.

Solution: Use SSR (Next.js, Nuxt, Remix) or static site generation. Content should be in the initial HTML response.

Step 6: Multiple Output Formats

If you have an API or data service, offer formats AI agents can easily parse:

• ?format=json — Structured data
• ?format=txt — Simple key=value pairs
• Default HTML — With machine-readable section at top

We do this at AgentDomainService:

GET /lookup/example.com?format=txt

fqdn=example.com
available=true
price_amount=12.99

AI agents can parse this in one line of code.

Step 7: Build Authority

AI models prioritize authoritative sources. Build authority by:

Original research — Publish data, benchmarks, case studies

Quality backlinks — Get cited by reputable sites

Technical depth — Go deeper than competitors

Regular updates — Fresh content signals relevance

Sites ranking in Google's top 10 are significantly more likely to be cited by AI models. Traditional SEO still matters.

Step 8: Test Regularly

Ask each AI assistant the questions you want to rank for:

• "What tools can check domain availability?"
• "How do I [your use case]?"
• "What's the best [your category]?"

Track whether you're being cited. Adjust content based on what works.

Quick Checklist

☐Create /llms.txt with site overview and key pages

☐Create /llms-full.txt with complete documentation

☐Update robots.txt to allow AI crawlers

☐Add JSON-LD structured data to key pages

☐Ensure pages are server-side rendered

☐Answer questions in first 2 lines of content

☐Use clear headings, lists, and tables

☐Include specific data and numbers

☐Offer multiple output formats for APIs

☐Test with ChatGPT, Claude, Perplexity, Gemini

The Future is AI-First

The web was built for browsers. But increasingly, AI agents are the first visitors to your site. They fetch pages, extract information, and present it to users who never click through.

This isn't a threat—it's an opportunity. Sites that speak the language of AI agents will capture traffic that others miss entirely.

We built AgentDomainService on these principles. Every page is SSR. Every response has machine-readable data. We have llms.txt, llms-full.txt, and structured data. The result? GPTBot has made thousands of requests to our site in just days.

Your site can do the same.

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Want to see these principles in action? Check agentdomainservice.com/llms.txt and agentdomainservice.com/llms-full.txt for examples.