{
 "acronym": "",
 "adoption": {
  "by": null,
  "level": "unmeasured",
  "probe_run": null
 },
 "aliases": [],
 "analog": "robots.txt, but declaring which agent protocols a site supports rather than which crawlers may visit",
 "collisions": [
  "Multiple unrelated, mutually incompatible specifications share the \"agents.txt\" name (see dispute): agents-txt.com's v1.0 protocol-declaration format, kaylacar/agents-txt's IETF-draft capability-declaration proposal, agentstxt.dev (a separate proposal whose IETF draft expired 2026-04-10), and the ad hoc allow/rate-limit format described in the arXiv paper 'Towards an Agent-First Web'"
 ],
 "discovery": {
  "mechanism": "Fixed filename at the site root",
  "path": "/agents.txt (well-known root path per all identified proposals; one proposal also allows /.well-known/agents.txt)"
 },
 "dispute": {
  "claims": [
   "agents-txt.com presents its v1.0 spec as authoritative and interoperable with A2A and RFC 9727",
   "kaylacar/agents-txt claims IANA filing and an active IETF Internet-Draft",
   "A Mastercard reference page independently reports the agentstxt.dev IETF draft as expired (2026-04-10) and describes 11+ competing proposals with no ratified standard",
   "An arXiv paper proposes yet another agents.txt grammar without referencing the others"
  ],
  "summary": "\"agents.txt\" names at least four non-converging, mutually incompatible proposals (agents-txt.com's v1.0, kaylacar/agents-txt's IETF-draft capability format, agentstxt.dev's expired-draft format, and an academic paper's own INI-style grammar), none of which has become a ratified or dominant standard."
 },
 "evidence": [
  {
   "claim": "agents-txt.com publishes a v1.0 'agents.txt Standard' spec: a text file at the site root declaring supported protocols (e.g. x402, mpp), with explicit sections relating it to A2A's AgentCard discovery and to RFC 9727's API Catalog",
   "date": "2026",
   "label": "VERIFIED",
   "url": "https://agents-txt.com/spec"
  },
  {
   "claim": "A separate GitHub proposal, kaylacar/agents-txt, describes itself as an open standard proposal for AI-agent capability declaration via a well-known URI, with IANA numbers #72/#73 'filed, under review' and an IETF Internet-Draft on Datatracker; the repository was created 2026-02-22 and last updated 2026-07-18",
   "date": "2026-07-18",
   "label": "VERIFIED",
   "url": "https://github.com/kaylacar/agents-txt"
  },
  {
   "claim": "A Mastercard merchant-developer reference page lists agents.txt (at agentstxt.dev, a third distinct effort) as an 'Emerging Standard (Draft)' whose IETF draft expired 2026-04-10, describing 'a fragmented landscape with 11+ competing proposals (agent-manifest.txt, agents-brief.txt, etc.)' and 'no ratified standard' (may require login: HTTP 401 on one check and 200 on another, 2026-09-06)",
   "date": "2026",
   "label": "REPORTED",
   "url": "https://developer.mastercard.com/merchant-cloud/documentation/tutorials-and-guides/agentic-commerce-guide/24/"
  },
  {
   "claim": "An arXiv paper, 'Towards an Agent-First Web', independently proposes its own agents.txt grammar (INI-style allow/rate-limit/content-format blocks per agent class) served at /.well-known/agents.txt, distinct from the other three",
   "date": "2026",
   "label": "VERIFIED",
   "url": "https://arxiv.org/html/2606.19116v1"
  }
 ],
 "form": "well-known-file",
 "governance": "None; at least three non-converging proposals (agents-txt.com, kaylacar/agents-txt, agentstxt.dev) each self-describe as \"the\" agents.txt standard, with no shared maintainer or reconciliation process found",
 "group": null,
 "history": [
  {
   "date": "2026-09-06",
   "note": "new record added during read-step verification; reclassified to the discover step after finding the name covers multiple non-converging, competing specifications"
  }
 ],
 "id": "agents-txt",
 "implementation": "prototype",
 "last_verified": "2026-09-06",
 "name": "agents.txt",
 "native_status": "\"An open standard proposal for declaring what AI agents can do on a website\" (kaylacar/agents-txt); a Mastercard developer-documentation page independently characterizes the space as \"IETF draft expired ... fragmented landscape with 11+ competing proposals ... no ratified standard\"",
 "origin": {
  "date": "2026-02-22",
  "org": "Contested; earliest identified public GitHub proposal is kaylacar/agents-txt"
 },
 "part_of": null,
 "parties": [
  "agent-site"
 ],
 "phase": "idea",
 "probe": {
  "method": "GET",
  "on_absent": "No agents.txt at the site root under any of the competing conventions; given the fragmentation, absence is a weak signal either way",
  "parse": "200 response with a text/plain body listing supported protocols (e.g. `Protocols: x402, mpp`) or per-agent directives, per whichever competing grammar the site chose to implement",
  "path": "{origin}/agents.txt"
 },
 "question": "Which agent-facing protocols (payments, auth, MCP, skills, A2A) does this site speak, and where?",
 "scope": "general",
 "spec_url": "https://agents-txt.com/spec",
 "step": "discover",
 "summary_md": "**Moved from the Read step to Discover.** agents.txt is not one specification but a name shared by at least four non-converging proposals for a site-root text file that declares which agent-facing protocols (payments, auth, MCP endpoints, Skills, A2A) a site supports and where to find them [1][2][3][4]. It is filed here under \"Discover\" (what is here, and where?) rather than \"Read\", since every version found declares protocol/capability presence and location, not page content, and one variant (agents-txt.com) explicitly frames itself as complementary to A2A's AgentCard discovery and RFC 9727's API Catalog [1].\n\nWhat it is (per the most detailed version found, agents-txt.com's v1.0): a plain-text file at the site root listing supported protocols, e.g. `Protocols: x402, mpp`, with directives for pointing agents at an A2A AgentCard, an MCP endpoint, or other machine-readable capability declarations [1]. A second, independently maintained proposal (kaylacar/agents-txt) describes a similar but not identical capability-declaration format and claims IANA filing (#72/#73, \"under review\") and an active IETF Internet-Draft [2]. A third effort, agentstxt.dev, is reported by a Mastercard developer-documentation page to have had its IETF draft expire on 2026-04-10, with that same source describing \"a fragmented landscape with 11+ competing proposals ... no ratified standard\" [3]. A fourth, academic proposal in the arXiv paper \"Towards an Agent-First Web\" defines yet another agents.txt grammar (INI-style `[agent-class]` blocks with `allow`/`rate-limit`/`content-format` fields) without referencing any of the other three [4].\n\nIt solves, in principle, the problem of an agent needing to discover a site's supported protocols in one request rather than probing each well-known path individually — a genuine gap, since A2A, MCP, x402, and other protocols each define their own discovery convention but nothing ties them together at a single site level.\n\nIt does not currently solve that problem in practice, because there is no single agents.txt to fetch: an agent cannot know, without trying multiple grammars, which of at least four incompatible conventions (if any) a given site implements. None of the identified efforts has IETF ratification, and the one with the most third-party visibility (agentstxt.dev) had its own draft lapse.\n\nCurrent state, as of this verification (September 2026): earliest dated public artifact found is the kaylacar/agents-txt GitHub repository, created 2026-02-22 and last updated 2026-07-18 [2]; agents-txt.com presents a v1.0 spec text with no stated publication date [1]; the Mastercard reference page's fragmentation characterization is dated to 2026 without a specific day [3]. No implementation count, adopter list, or resolution among the competing proposals was found.\n\nWhat is disputed: everything about precedence, authorship, and which (if any) proposal will consolidate the space. This record should be treated as thin pending a resolution or a dominant implementation emerging.",
 "track": "community",
 "version": {
  "date": null,
  "label": "agents-txt.com: v1.0; competing proposals carry no shared version"
 }
}