# llms.txt vs Agentic Resource Discovery

They answer different questions: llms.txt is a step 4 (Read) standard, Agentic Resource Discovery step 1 (Discover), so they are not substitutes.

[4 Read](/category/read/) [llms.txt](/protocols/llms-txt/) · [1 Discover](/category/discover/) [Agentic Resource Discovery](/protocols/ard/)

|  | [llms.txt](/protocols/llms-txt/) | [Agentic Resource Discovery](/protocols/ard/) ARD |
| --- | --- | --- |
| Lifecycle step | 4 Read: Give me the content | 1 Discover: What is here, and where? |
| Answers | Where can an agent find a concise, curated map of a site's content, written for language models rather than browsers? | Where are an organization's discoverable agentic resources (MCP servers, A2A agents, skills, registries), and how can they be found by search rather than pre-installed one at a time? |
| Governed by | Jeremy Howard / Answer.AI; maintained as an open proposal in the AnswerDotAI/llms-txt GitHub repository with a public Discord for implementation discussion | Authored by individuals at Google, Microsoft and Hugging Face (Junjie Bu, R.V. Guha, Shaun Smith); published as an open GitHub project (ards-project/ard-spec) with no formal standards body yet; contributions acknowledged from AWS, Cisco, Databricks, GitHub, GoDaddy, Nvidia, Salesforce and Snowflake |
| Status (issuer's words) | "This is v2 of the proposal" — explicitly a community proposal open for input, not a standards-track document | Proposal |
| Phase | draft | draft |
| Version | v2 (2026-08) | v0.91 (2026-08-26) |
| Form / transport | well-known file | well-known file |
| Found at | /llms.txt (or /<path>/llms.txt, e.g. /docs/llms.txt) | /.well-known/ard.json |
| Adoption | claimed — Rankability (Tranco top-1000, June 2026: 8.7%) and SE Ranking (~300,000 domains analyzed: 10.13%) — independent third-party publisher-side counts, not our own probe | observed — agenticresources.dev own probe, 2026-09-04 |
| Evidence | 4 verified, 4 reported | 2 verified, 2 reported |
| Primary use case | Serve readable content to agents | Let agents discover my API or service |
| Last verified | 2026-10-19 (current) | 2026-10-19 (current) |
| Specification | [https://llmstxt.org](https://llmstxt.org) | [https://raw.githubusercontent.com/ards-project/ard-spec/main/spec/ard.md](https://raw.githubusercontent.com/ards-project/ard-spec/main/spec/ard.md) |

## When to use which

- Choose llms.txt when your question is “Where can an agent find a concise, curated map of a site's content, written for language models rather than browsers?” and you accept its maturity: phase draft, adoption claimed (Rankability (Tranco top-1000, June 2026: 8.7%) and SE Ranking (~300,000 domains analyzed: 10.13%) — independent third-party publisher-side counts, not our own probe).
- Choose Agentic Resource Discovery when your question is “Where are an organization's discoverable agentic resources (MCP servers, A2A agents, skills, registries), and how can they be found by search rather than pre-installed one at a time?” and you accept its maturity: phase draft, adoption observed (agenticresources.dev own probe, 2026-09-04).

Guidance is derived from the two records (question, phase, adoption, prerequisites, pairings), not from opinion. Each record's page carries its numbered references.

## Read the full articles

- [llms.txt](/protocols/llms-txt/): Where can an agent find a concise, curated map of a site's content, written for language models rather than browsers?
- [Agentic Resource Discovery](/protocols/ard/): Where are an organization's discoverable agentic resources (MCP servers, A2A agents, skills, registries), and how can they be found by search rather than pre-installed one at a time?

Ask the MCP server to compare any two: the compare-protocols prompt, or get on both ids. [Connect](/connect/).

[llms-txt.json](/data/protocols/llms-txt.json) · [ard.json](/data/protocols/ard.json) · [Markdown](/compare/llms-txt-vs-ard/index.md)