How should we call the context file, and what should be inside? This summer, the agentic coding community took a few steps toward agreeing on a standard.

The bikeshed-prone question of how the file should be named seems to be settled: the generic context file will be called AGENTS.md.

Origins

Context files were popularized by Anthropic through their agentic coding assistant, Claude Code. When run in a directory, Claude Code automatically loads any file called CLAUDE.md and attaches its content to the request sent to the LLM.

A screenshot from an Anthropic article explaining what to include in a CLAUDE.md file. The list includes: Common bash commands, Core files and utility functions, Code style guidelines, Testing instructions, Repository etiquette, and Developer environment setup.

It’s a neat idea! When we set up a good context file, the agent’s performance gets better. As it gets better, we tend to use it more, which helps us further improve and refine the context. It’s a virtuous loop.

It’s also free advertising for Anthropic: as CLAUDE.md files proliferate across the open-source space, more users discover Claude Code.

Need for a standard

The last 12 months have seen a rapid multiplication of coding assistants. Each came with their own flavor of the context file idea. The differences come in two aspects: the filename (so the tool can autoload it) and the best practices for writing one.

Regarding the file name:

As for the best practices, each provider will have their own take on what’s best to put in the model instructions. However, these guidelines are often applicable across models. Moreover, the 2025 coding tools landscape is heterogeneous: most open-source projects will have contributors using different coding agents.

Welcome information printed out by Gemini CLI, including a suggestion to create a GEMINI.md file with agent guidance

All this creates an opportunity to supersede (or supplement) the proprietary standard with a generic convention for context files. Defined in one place per project, these context files should be loaded by any coding agent that wants to play well with the rest of the ecosystem.

AGENT.md vs AGENTS.md

Of the agents listed above, both AMP and OpenAI used generic names: AGENT.md and AGENTS.md, respectively. This made them obvious candidates for the standard name.

In May, Quinn from AMP proposed that the community converge on AGENT.md. They had secured the agent.md domain to host guidelines and best practices, and the agents.md domain was unavailable.

A tweet from Quinn Slack from AMP suggesting the community standardize on AGENT.md. He mentions that they picked AGENT.md in Amp, and then OpenAI picked AGENTS.md for Codex, and argues for AGENT.md.

Then, OpenAI announced that they had bought the other domain (agents.md ) and would publish their own take on best practices there.

A tweet from Alexander Embiricos announcing that OpenAI has acquired the AGENTS.md domain. He states the name is intentionally neutral and open and asks for community contributions for best practices.

At which point, AMP honorably responded that they would align with AGENTS.md:

A tweet from Quinn Slack of AMP agreeing to align with the AGENTS.md standard. He announces that Amp will soon support and recommend AGENTS.md, with backward compatibility for the old AGENT.md format.

AGENTS.md becomes the convention

A screenshot of the introduction section of the agent-rules.org website. It explains that Agent Rules proposes a unified configuration file, AGENTS.md, to guide AI coding agents, inspired by projects like Editor Config and Conventional Commits.

Roo Code added support for AGENTS.md in July. AMP has already announced they will recommend AGENTS.md and set their agent.md website to redirect to OpenAI’s agents.md .

It seems AGENTS.md it is, and we can go back to vibe coding.

For proprietary agents that don’t want to join in, good old symlinks do the job:

ln -s AGENTS.md CLAUDE.md
ln -s AGENTS.md GEMINI.md

Next steps

The next frontier will be agreeing on the generic best practices for what to put in those files.