Patrick Neeman, writing for UX Collective, compares today’s AI interfaces to the browser wars:

[Jeffrey] Zeldman did not invent the specifications, he did something harder: He convinced an entire industry that shared conventions were worth fighting for, and he won. Zeldman changed the world with a stance, not a specification and we should thank him for it.

We are living through that moment again, this time for the interfaces we wrap around models, the skills we scaffold on top of them and representations they mean.

The browsers have new names: ChatGPT, Claude, Gemini, and Copilot each handle the same task their own way, with their own conventions for parsing content, showing reasoning, citing a source, and asking permission before they act.

The connection to design systems is structural. Browser standards gave different products a shared foundation without forcing them to look identical. Neeman doesn’t claim that the conventions for AI interfaces are settled; he proposes design systems as the way practitioners can develop and share them:

The core move was to pull structure, presentation, and behavior into distinct layers so each could change without breaking the others. That one idea outlived every specific technology it was built on.

It is why a design system works at all.

When Brad Frost introduced atomic design, he was extending the same instinct: stop shipping pages, start composing interfaces from small, shared, recombinable parts. Design systems are the standards movement’s direct descendant, and they are the closest thing we have to a working model for AI interface conventions.

That working model is already appearing in the Markdown files agents use as project-level contracts:

Agents increasingly take their instructions from plain text files that sit beside the work — AGENTS.md for how an agent should behave in a project, SKILL.md for what a capability can do, README.md for the context around both.

This is the new semantic layer. It is markup again, written in Markdown and read by a model instead of a browser.

[…]

A design.md that carries your design system’s patterns, tokens, and rules into every agent that touches the product. An accessibility.md that states the non-negotiables in language a model can follow. A content.md that fixes voice, terminology, and the content model.

Neeman also points to a broader protocol stack taking shape:

You are not waiting for this to begin. It has begun. A partial map of the standards taking shape right now:

• Model Context Protocol — a shared way for a model to reach tools, data, and context, already adopted across rival platforms and now stewarded by a neutral foundation.
• A2UI — a declarative protocol for agents to describe interfaces that render natively across web, mobile, and desktop, keeping what the interface is separate from how each client draws it.
• Agent2Agent — an open protocol for agents to discover one another and collaborate across frameworks and vendors, launched by Google and handed to the Linux Foundation.
• The W3C AI Agent Protocol Community Group — a grassroots group drafting open rules for a trustworthy web of agents.
• Agent identity work — cross-body efforts, at the W3C and beyond, to verify who an agent is and what it is allowed to do before it acts.

None of these is finished, and that is the opening. The conventions are still soft enough to shape, which is exactly where Zeldman’s coalition made its difference.