Agent Readability Spec (ARS) vs AGENTS.md
The map lists them as complementary: sites and agents commonly implement both.
| Agent Readability Spec ARS | AGENTS.md | |
|---|---|---|
| Lifecycle step | 4 Read: Give me the content | 4 Read: Give me the content |
| Answers | How readable is this site's content for AI agents, and what specifically should be fixed? | What build, test, and convention instructions should a coding agent follow in this repository? |
| Governed by | Vercel; published in Vercel's own Knowledge Base with no external standards process | Agentic AI Foundation (AAIF), a Linux Foundation project |
| Status (issuer's words) | A specification and scoring checklist, not a protocol; framed as best practices to implement voluntarily | "An open format... regardless of which coding agent you use"; explicitly not proprietary to any one tool |
| Version | current (last updated 2026-03-23 per a secondary source; no version number or publication date is given on the page itself) (2026-03) | current site guidance (living document) (2026-09) |
| Form / transport | document format | well-known file |
| Found at | none | AGENTS.md |
| Implementation | shipping | multi-implementation — agents.md (site claims over 60,000 AGENTS.md files across open-source GitHub repositories, via a path:AGENTS.md NOT is:fork NOT is:archived code search) |
| Evidence | 2 reported, 1 verified | 2 reported, 1 verified |
| Primary use case | Serve readable content to agents | Serve readable content to agents |
| Last verified | 2026-10-23 (current) | 2026-10-23 (current) |
| Specification | https://vercel.com/kb/guide/agent-readability-spec | https://agents.md |
When to use which
- Choose Agent Readability Spec when your question is “How readable is this site's content for AI agents, and what specifically should be fixed?” and you accept its maturity: status "A specification and scoring checklist, not a protocol; framed as best practices to implement voluntarily", implementation shipping.
- Choose AGENTS.md when your question is “What build, test, and convention instructions should a coding agent follow in this repository?” and you accept its maturity: status ""An open format... regardless of which coding agent you use"; explicitly not proprietary to any one tool", implementation multi-implementation (agents.md (site claims over 60,000 AGENTS.md files across open-source GitHub repositories, via a path:AGENTS.md NOT is:fork NOT is:archived code search)).
Read the full articles
- Agent Readability Spec: How readable is this site's content for AI agents, and what specifically should be fixed?
- AGENTS.md: What build, test, and convention instructions should a coding agent follow in this repository?