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Layer 4 - Advanced

Weight: 15% of open score

Layer 4 checks for next-generation AI integration signals. Most sites will not have these - absence is info, not a failure. These checks reward early adopters.

well-known-ai - .well-known AI plugin manifest

Possible statuses: pass / info

Probes:

  • /.well-known/ai-plugin.json
  • /.well-known/openai-manifest.json

Why it matters: The .well-known/ai-plugin.json format was popularised by ChatGPT Plugins and is still used by several AI agent frameworks to discover service capabilities automatically.

llms-txt-mcp - MCP server endpoint documented in llms.txt

Possible statuses: pass / info

Parses llms.txt for links pointing to an MCP endpoint. Matches on URL paths (/mcp, /mcp.json, /.well-known/mcp*) or keywords (mcp, model context protocol) in link text or section headings.

llms-txt-nlweb - NLWeb endpoint documented in llms.txt

Possible statuses: pass / info

Parses llms.txt for links to a NLWeb conversational endpoint. Matches URL paths (/ask, /nlweb) or the keyword nlweb. The keyword ask alone is excluded as it is too generic.

llms-txt-a2a - A2A agent endpoint documented in llms.txt

Possible statuses: pass / info

Parses llms.txt for Agent-to-Agent (A2A) protocol endpoints. Matches URL paths (/a2a) or keywords (a2a, agent2agent, agent-to-agent).

llms-txt-chat-api - Chat / completions API documented in llms.txt

Possible statuses: pass / info

Parses llms.txt for links to OpenAI-compatible chat APIs. Matches URL paths (/chat/completions, /v1/completions, /v1/chat) or keywords (openai-compatible, openai compatible, chat completions).