---
title: "Content negotiation: glossary: Agent Ready HTML"
description: "Content negotiation: The HTTP mechanism where the client states preferred formats in the Accept header and the server picks a representation for the same URL."
canonical: https://agentreadyhtml.com/glossary/content-negotiation/
site: "Agent Ready HTML"
last_updated: 2026-11-04
section: "Glossary"
---

# Content negotiation: glossary: Agent Ready HTML

> Content negotiation: The HTTP mechanism where the client states preferred formats in the Accept header and the server picks a representation for the same URL.

Source: https://agentreadyhtml.com/glossary/content-negotiation/
Site: Agent Ready HTML
Last reviewed: 2026-11-04

# Content negotiation

In short

The HTTP mechanism where the client states preferred formats in the Accept header and the server picks a representation for the same URL. Example: Vercel serves its blog as markdown when a request sends Accept: text/markdown. Related terms: Accept header, Markdown negotiation, Markdown twin, Vary: Accept, Content-Signal.

## Source of the example

The example in the summary above is from [vercel.com](https://vercel.com/blog/making-agent-friendly-pages-with-content-negotiation), read 4 November 2026.

## Where it shows up on this site

-   [Guide: serve markdown on request](https://agentreadyhtml.com/guides/serve-markdown-on-request/)

## Neighbouring terms

-   [Accept header](https://agentreadyhtml.com/glossary/accept-header/): The request header that lists media types a client will take, with optional q weights.
-   [Markdown negotiation](https://agentreadyhtml.com/glossary/markdown-negotiation/): Content negotiation where Accept: text/markdown returns the page as markdown with Content-Type text/markdown.
-   [Markdown twin](https://agentreadyhtml.com/glossary/markdown-twin/): A markdown copy of a page at a predictable URL, such as page.md or page.html.md.
-   [Vary: Accept](https://agentreadyhtml.com/glossary/vary-accept/): A response header telling caches that the body depends on the Accept header, so HTML and markdown are stored separately.
-   [Content-Signal](https://agentreadyhtml.com/glossary/content-signal/): A declaration of permitted AI uses (ai-train, search, ai-input), sent as a robots.txt line or a response header.

## Sources

1.  [vercel.com](https://vercel.com/blog/making-agent-friendly-pages-with-content-negotiation) https://vercel.com/blog/making-agent-friendly-pages-with-content-negotiation, read 4 November 2026

Last reviewed 4 November 2026

Edition

Crawl

2026-11-04

Page updated

2026-11-04

Method

How the viewer reads a page, how a file is graded and how a platform is scored: [the method page](https://agentreadyhtml.com/method/).