Glossary

Short definitions of design system terms: drift, design tokens, modes, token pipelines and more.

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Automatic pull request: An automatic pull request is one a tool opens or updates by itself when the source changes, so a design update arrives as a pull request without anyone starting the delivery.

Bypass: A bypass is code that skips the design system where a token or component exists, such as a hard-coded colour or a rebuilt button.

Change class: A change class says how much a design change can affect code that already uses a component: breaking, additive or cosmetic.
Code index: A code index is a structured record of facts read from a repository, such as component names, props and usages, kept instead of the code itself.
Component health: Component health is a score for one component: how closely it follows its design and the tokens, and how well-kept its API and accessibility are. In FISYCO it runs from 0 to 100.
Consumer repository: A consumer repository is a product repository that uses a design system's ui-kit as a dependency instead of containing it.

Design system assurance: Design system assurance is the practice of proving, at any moment, that production still matches the design system the team approved.
Design system drift: Design system drift is the gap between the design a team approved and the code that ships to customers.
Design system health: Design system health measures whether the product that uses a design system still matches it: divergences, their reach, bypasses and time to fix.
Design system MCP server: A design system MCP server gives AI coding agents the design system as tools: components, tokens, team rules and a check of the code they write.
Design system patch: A design system patch is a code change that brings code back in line with the design system, proven before it ships and delivered as a pull request.
Design token: A design token is one design decision, such as a colour, a spacing step or a type size, with a name that design and code both use.
DTCG: DTCG (Design Tokens Community Group) is the W3C community group behind the Design Tokens Format Module, and the usual short name for that format: JSON with typed tokens and references.

Mode: A mode is one set of values for the same tokens, such as a light or a dark theme.

Primitive and semantic tokens: A primitive token names a raw value, like blue 500. A semantic token names what a value is for, like the accent background, and points at a primitive.

Reach: Reach is how much of the product a design token, component or divergence touches, counted as the places in code that use it or are affected by it.

SVG icon sprite: An SVG icon sprite is one SVG file that holds every icon as a symbol. A page draws each icon by reference instead of loading it as its own file.

Time to fix: Time to fix is how long a design system finding stays open, from the day it's first seen to the day it's resolved.
Token pipeline: A token pipeline is the automated path that takes design tokens from their source, such as Figma, into code as a reviewed change.

Variant mapping: Variant mapping links each Figma variant property and its values to the code props and values that render the same thing.