# Knowledge Base

> Plain-language guides to every protocol agentgrade checks for.

## About

- [Getting Started — Make Your Site Agent-Ready](https://agentgrade.com/kb/getting-started): Quick checklist to make your site discoverable and usable by AI agents.
- [Understanding Your Score](https://agentgrade.com/kb/understanding-your-score): How agentgrade scores your site, what verified vs declared means, and how to improve.
- [Cloudflare & Agent Access](https://agentgrade.com/kb/cloudflare-agent-access): Why Cloudflare blocks agent traffic and how to configure it for agent accessibility.
- [About Scanning](https://agentgrade.com/kb/about-scanning): How agentgrade scans sites, what data it collects, and how to opt out.

## Payments

- [Comparing Payment Protocols](https://agentgrade.com/kb/comparing-payment-protocols): x402 vs MPP vs L402 — when to use each machine payment protocol.
- [x402 — HTTP Payment Protocol](https://agentgrade.com/kb/x402): The HTTP 402 payment protocol that lets agents pay per-request with USDC on Base. Specification, comparison with traditional API monetization, ecosystem, and how to implement.
- [MPP — Machine Payment Protocol](https://agentgrade.com/kb/mpp): Micropayment protocol using pathUSD on the Tempo network for sub-second agent payments.
- [SPT — Stripe Shared Payment Tokens](https://agentgrade.com/kb/spt): Stripe card payments for AI agents via Shared Payment Tokens and the MPP 402 flow.
- [L402 — Lightning Payments](https://agentgrade.com/kb/l402): Bitcoin Lightning Network payments for API access using macaroons and invoices.
- [x-payment-info — OpenAPI Payment Discovery](https://agentgrade.com/kb/x-payment-info): Pre-request payment discovery via OpenAPI extensions so agents know pricing before triggering a 402.
- [Bazaar — Service Discovery](https://agentgrade.com/kb/bazaar): The x402 service catalog that lets agents discover and browse paid API endpoints.

## Concepts

- [How AI Agents Actually Browse the Web](https://agentgrade.com/kb/how-ai-agents-browse): How ChatGPT, Perplexity, and Gemini retrieve and process web content — and what it means for your site.
- [Infrastructure — Cache, Errors, Redirects](https://agentgrade.com/kb/infrastructure): HTTP-level behaviors agents rely on: cache headers, structured errors, HTTPS redirect, sitemap.
- [JavaScript-Rendered Sites and Agent Visibility](https://agentgrade.com/kb/javascript-rendering): Why client-rendered SPAs are invisible to AI crawlers, what it does and does not break, and how to fix it.

## Discovery

- [MCP — Model Context Protocol](https://agentgrade.com/kb/mcp): The open standard for connecting AI assistants to external tools. Spec, transport options, ecosystem, authentication, debugging, and how to implement an MCP server.
- [OpenAPI — API Specification](https://agentgrade.com/kb/openapi): Machine-readable API description that tells agents what endpoints exist and how to call them.
- [llms.txt — LLM Context File](https://agentgrade.com/kb/llms-txt): Plain-text file that explains your service to large language models.
- [llms-full.txt — Full Content for LLMs](https://agentgrade.com/kb/llms-full-txt): Companion to llms.txt: the entire site text concatenated into one file so non-browsing LLMs can ingest your content in a single fetch.
- [agents.txt — Agent Access Policies](https://agentgrade.com/kb/agents-txt): Defines what AI agents are allowed to do on your service.
- [Organization JSON-LD — Entity Graph for Agents](https://agentgrade.com/kb/organization-jsonld): Declare your site as a schema.org Organization with sameAs links to your other canonical surfaces. The linked-data signal LLMs use to consolidate scattered surfaces into one entity in their knowledge graph.
- [robots.txt for Agents](https://agentgrade.com/kb/robots-txt): Agent-specific directives in robots.txt that signal your site welcomes AI crawlers.
- [Skill file (SKILL.md)](https://agentgrade.com/kb/skills): A markdown file with YAML frontmatter that tells agents how to use your service.

## Identity

- [Identity Protocols](https://agentgrade.com/kb/identity): Decentralized identity standards that let agents verify who owns a domain.

## Capabilities

- [Content Negotiation for AI Agents](https://agentgrade.com/kb/content-negotiation): How to serve agent-optimized responses based on User-Agent and Accept headers.
- [Web Bot Auth (RFC 9421)](https://agentgrade.com/kb/web-bot-auth): How AI agents prove their identity with cryptographic HTTP message signatures.
- [A2A — Agent-to-Agent Protocol](https://agentgrade.com/kb/a2a): Google's protocol for AI agents to discover and communicate with other agents.
- [WebMCP — Browser Agent Interaction](https://agentgrade.com/kb/webmcp): A W3C draft protocol that lets browser-based AI agents interact with websites through annotated forms.