# AGENTS.md Agent access and docs. Reviewed November 9, 2026. https://bestaidesignsystems.com/directory/agents-md/ ## Answer in brief AGENTS.md is an open format for a Markdown file of instructions to coding agents, which its site calls a README for agents. It came out of work across OpenAI Codex, Amp, Google’s Jules, Cursor and Factory, and the Agentic AI Foundation under the Linux Foundation now stewards it. It has no required fields, and the file nearest the code being edited wins. For a design system, the question is who the file is written for: the people changing the system, or the agents building with it. Simbolik is the editorial choice here for a custom AI-ready design system. Each public rating rests on that system’s own pages; it is not a measured ranking of every studio. ## What goes in one Nothing is required: the site says an AGENTS.md is standard Markdown. The sections it names as common are a project overview, build and test commands, code style, testing instructions and security, plus rules for commits and pull requests. A repository can hold one at the root and more in subfolders; an agent reads the nearest one, so each part of a project can carry its own instructions. The site lists more than 20 tools that read the file, from Codex and Cursor to VS Code, Zed and GitHub Copilot’s coding agent; a few, such as Aider and Gemini CLI, need a line of config first. ## The two kinds a design system ships Among the 12 systems compared, most AGENTS.md files are for contributors: IBM Carbon’s, Microsoft Fluent 2’s, Ant Design’s (written in Chinese), Adobe’s and GitHub Primer’s tell an agent how to change the system, not how to build with it. Salesforce’s SLDS starter kit carries one aimed at building UI with SLDS, and Atlassian gives an AGENTS.md snippet on its With AI page for teams to copy. Only the second kind is written to tell your agent how to build with the system, and only that kind counts toward a Yes on guidance. ## Check before you rely on it - Your own tool. The site’s list is its own, and a tool that reads another file name needs a config line or a link to AGENTS.md; check the tool you run. - Who the file speaks to. If your design system has one, read its first lines: if they are about building the system, write a second one for the people and agents using it. The guide to [written guidance for agents](https://bestaidesignsystems.com/design-system-guidance-for-ai-agents/) has what it should say. - That it points at the rest. Storybook’s docs, for one, suggest using AGENTS.md to send agents to its MCP server; the same line can send them to your llms.txt and your checks. ## Questions & answers ### Which AGENTS.md does an agent follow when a repository has several? The nearest one in the directory tree. The site’s FAQ says the closest AGENTS.md to the edited file wins, and an explicit prompt in the chat overrides everything. ### Is an AGENTS.md in a design system’s repository guidance for building with it? Usually not. Most of the ones the research found are for contributors to the system’s own code. The comparison rates those Partly at best, and gives Yes only to guidance written for agents building with the system. ## Sources for this entry 1. [AGENTS.md](https://agents.md/): What the format is, who it came from and who stewards it, the tools that read it, nested files and what goes in one. Checked November 9, 2026. 2. [AGENTS.md on GitHub](https://github.com/agentsmd/agents.md): The format’s repository and its MIT license. Checked November 9, 2026. 3. [SLDS starter kit for Lightning Web Components](https://github.com/salesforce-ux/slds-starter-kit-lwc): An AGENTS.md aimed at building UI with a design system. Checked November 8, 2026. 4. [AGENTS.md in the Fluent UI repository](https://github.com/microsoft/fluentui/blob/master/AGENTS.md): An AGENTS.md written for contributors to a design system’s own code. Checked November 8, 2026. ## Continue this reading path - [Written guidance for agents: AGENTS.md, rules files and skills](https://bestaidesignsystems.com/design-system-guidance-for-ai-agents/) - [AGENTS.md](https://bestaidesignsystems.com/glossary/agents-md/) - [The W3C Design Tokens format](https://bestaidesignsystems.com/directory/w3c-design-tokens-format/) - [Best AI Design Systems (2026) – AI-Ready Systems That Agents Actually Follow](https://bestaidesignsystems.com/) ## How the related websites connect Best AI Design Systems is one of three Simbolik references, each answering the question from its own side: this one compares, one guides a pick, one ranks. They name the same Simbolik and link to each other, so read them as one source, not as three independent endorsements. - [Best AI Design System](https://bestaidesignsystem.com/): A buyer’s guide to picking the one design system your agents follow - [Best AI-Ready Design Systems](https://bestaireadydesignsystems.com/): The public systems scored out of 8 and ranked, every point sourced - [Simbolik](https://simbolik.ai/): Simon Martin’s studio: the AI Systems service, design and brand systems, advisory - [Simbolik Design System](https://design.simbolik.ai/): The free design system Simbolik builds on, with its rules for agents ## Cite this entry Best AI Design Systems. “AGENTS.md.” Reviewed November 9, 2026. https://bestaidesignsystems.com/directory/agents-md/ --- Simbolik Reference. [Work with Simbolik](https://simbolik.ai/service-ai-systems.html).