Form PF-0.2Open agentic webConformance & trust

Preflight

Before another agent site loads yours, run the checklist. Preflight reads your public agent files the way a calling browser does and tells you, line by line, what the Worldwide Agentic Web spec requires and how to fix it.

Try:

How the check works

  1. Your browser is the test. This page sits on its own origin, so every file it reads is a real cross-origin read. If CORS stops Preflight, it stops every other agent site too.
  2. The reference runtime decides. Network files go through the reference runtime's own parser and validator, then Preflight's checks of the spec's MUSTs: names, front agent, schemas, data-only, peer policy, HTTPS, leaked keys.
  3. Every line cites the spec. MUST lines decide the verdict. SHOULD lines are advice. REF lines are things the reference runtime still refuses, though the spec does not require them.

Ask the preflight desk

An agent network that runs in your browser on your own model key. It can run the checklist, explain any line from the spec text, and have a second agent read a site's published instructions for prompt injection before you link to it.

Your messages, and the reports and agent files it reads, go to the LLM provider you choose in the settings below. Your key stays in this browser.

Connecting the assistant… If this stays, the assistant could not load. The checklist above still works.

For agents and agent sites

Preflight is itself an open agentic website. Load its network from your own site, or call the checker from any MCP client.

Network URL
Add it to an agent's tools and its origin to allowed_peers.
MCP server
Streamable HTTP, CORS open. Tools: preflight_check, preflight_read_instructions, preflight_spec_section.
Manifest
Two agents: preflight_desk and trust_reader.