The standards of the agentic web
Updated 2026-07-31
Reference pages for the specifications AI agents run on — what each one is, where it actually stands (working group, draft, RFC, convention), the agent-relevant mechanics with wire examples, and which AgentGrade checks cover it. Raw specs are written for implementers; these pages are written for site owners deciding what to ship.
| Standard | Layer | Governed by | Status |
|---|---|---|---|
| RFC 8615 | Discovery | IETF · IANA registry | Proposed Standard (IETF), published May 2019; a revision draft (rfc8615bis) is circulating as an individual draft |
| llms.txt | Discovery | Community (llmstxt.org) | Community convention (llmstxt.org); no standards body, not IANA-registered; measured consumption is minimal |
| RFC 9309 | Discovery | IETF | Proposed Standard (IETF, 2022) — the formalization of 30 years of robots.txt practice |
| RFC 9110 | Discovery | IETF | Internet Standard (IETF, 2022) — the HTTP core specification |
| RFC 9727 | Discovery | IETF · IANA registry | Proposed Standard (IETF httpapi WG), published June 2025 |
| MCP | Capability | MCP project (open) | Open specification with broad multi-vendor adoption; originated by Anthropic in late 2024 |
| A2A | Capability | Linux Foundation | v1.0.0 stable (March 2026), governed by the Linux Foundation; agent-card.json is IANA-registered |
| WebMCP | Capability | W3C Web Machine Learning CG | W3C Community Group draft (not on the standards track); Chrome origin trial since Chrome 149 (June 2026), Edge opt-in trial |
| x402 | Payments | x402 Foundation (Linux Foundation) | Production protocol; stewarded by the x402 Foundation under the Linux Foundation since July 2026 |
| ACP / UCP / AP2 | Payments | ACP: OpenAI/Stripe · UCP: UCP Tech Council · AP2: FIDO Alliance (donation announced April 2026) | ACP: OpenAI + Stripe, Sept 2025 · UCP: Google + Shopify, Jan 2026 · AP2: Google, Sept 2025 (FIDO donation announced Apr 2026) — none an IETF standard |
| RFC 9421 | Identity & trust | IETF | Proposed Standard (IETF), published February 2024 |
| Web Bot Auth | Identity & trust | IETF webbotauth WG | Individual drafts under a chartered IETF working group (webbotauth, formed October 2025); not yet an RFC |
| RFC 9116 | Identity & trust | IETF | Informational (IETF), published April 2022 |
| OAuth Discovery | Identity & trust | IETF OAuth Working Group | RFC 8414: Proposed Standard, June 2018 · RFC 9728: Proposed Standard, April 2025 |
| RFC 7591 | Identity & trust | IETF OAuth Working Group | Proposed Standard (IETF), published July 2015; deprecated by MCP in favor of Client ID Metadata Documents |
The protocol guides in the Knowledge Base cover how to implement each of these; scan your site to see which you already ship.