ReadMe against Fern on what an agent reads
In short
ReadMe: With LLMs.txt on, a request for a missing .md page returns a markdown 404 with agentTools front matter pointing to llms.txt and a search URL. Fern leads on markdown on request, 2 to 1; ReadMe: Markdown for Agents is a documented setting under AI Discoverability; defaults vary by setting.
The sourced difference
ReadMe scores each project against the Agent-Friendly Docs spec inside its AI Discoverability panel; Fern documents agent directives prepended to every markdown page that point agents to .md URLs and llms.txt. Source, read 4 November 2026.
The rubric side by side
| Key | ReadMe | Fern |
|---|---|---|
| Content in the initial HTML | 2, on by default | 2, on by default |
| Real status codes | 2, on by default | 2, on by default |
| llms.txt generation | 2, on by default | 2, on by default |
| llms.txt linking | 2, on by default | 2, on by default |
| Markdown on request | 1, with setup | 2, on by default |
| JSON-LD output | 0, not offered | 0, not offered |
| OpenAPI exposure | 2, on by default | 2, on by default |
| Fenced, tagged code | 2, on by default | 2, on by default |
| Total | 13 of 16 | 14 of 16 |
The two differ on 1 of the numeric keys: markdown on request. Evidence for each score is on the profiles of ReadMe and Fern.
Verdicts by reader
- Technical SEO
- ReadMe shows a grade in the product; Fern changes what agents receive.
- Docs owner
- ReadMe gives a checklist to work through; Fern acts by default.
- Front-end developer
- Both serve markdown twins; Fern also renders endpoint pages as property lists.
What each leaves undone
ReadMe
- Does not promise that an agent will request llms.txt.
- Does not keep a custom llms.txt in sync with content changes.
Fern
- Does not give individual pages their own llms.txt.
- Does not serve custom llms.txt files for non-default locales.
Work left to the developer: ReadMe, Low: review the AI Discoverability toggles; a custom llms.txt stops automatic updates. Fern, Low: write frontmatter descriptions; use llms-only and llms-ignore controls where needed.
Sources
- docs.readme.com: the difference https://docs.readme.com/main/docs/ai-discoverability, read 4 November 2026
- Fern: documentation https://buildwithfern.com/learn/docs/changelog, read 4 November 2026
Last reviewed 4 November 2026