# Conformance check

Quality and checks. Reviewed November 9, 2026. https://bestaidesignsystems.com/glossary/conformance-check/

## Answer in brief

A conformance check is a program that reads what was built, a page, a stylesheet, a pull request, and lists every place it leaves the design system: a color or size written by hand where a design token belongs, a component rebuilt instead of used. It runs the same way every time, so it catches what a person reviewing agent output by eye misses, and it gives the agent a list it can fix.

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.

## In an AI-ready design system

A design system an agent can read is half the job; the other half is knowing when the agent did not follow it. Simbolik’s free design system ships a [checker](https://design.simbolik.ai/docs/check-your-site/) that, in its own words, "lists every value written by hand and every component rebuilt by hand", with a JSON report for scripts and agents. A finding that cannot be fixed is written down with its reason, never switched off. This reference is checked the same way, by the checker of the design system it is built on.

## What to ask of a design system

Ask whether it ships a check, and what the check reads: values, components, or both. Then ask whether its output is something an agent can act on. The [acceptance checks guide](https://bestaidesignsystems.com/checking-ai-output-against-a-design-system/) puts a check like this first, before any person looks.

## Questions & answers

### Is a linter a conformance check?

It can be one. Atlassian’s ESLint plugin has a rule that enforces design tokens rather than hard-coded values, and GitHub Primer’s MCP server has a tool that checks CSS for its design token use. A conformance check is any such program pointed at the whole design system’s rules, not only at code style.

## Sources for this entry

1. [Check your site, Simbolik Design System](https://design.simbolik.ai/docs/check-your-site/): A checker that lists every value written by hand and every component rebuilt by hand. Checked November 9, 2026.
2. [ensure-design-token-usage, Atlassian ESLint plugin](https://atlassian.design/components/eslint-plugin-design-system/ensure-design-token-usage/usage): A lint rule that enforces design tokens rather than hard-coded values. Checked November 9, 2026.
3. [Primer MCP](https://primer.style/product/getting-started/foundations/mcp/): The `lint_css` tool, which checks CSS for Primer design token use. Checked November 9, 2026.

## Continue this reading path

- [Acceptance: checking an agent’s output against the design system](https://bestaidesignsystems.com/checking-ai-output-against-a-design-system/)
- [Design drift](https://bestaidesignsystems.com/glossary/design-drift/)
- [A test set: prompts that measure an agent against your design system](https://bestaidesignsystems.com/design-system-test-prompts/)
- [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. “Conformance check.” Reviewed November 9, 2026. https://bestaidesignsystems.com/glossary/conformance-check/

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