Storybook Workshop

storybook-workshop

A story is not a demo. It is the component's executable documentation: the artefact an agent reads to learn what the component accepts, and the harness that catches a contrast or focus defect while the component is still in isolation. Stack-agnostic — the tool is Storybook, the discipline is not.

Lifted out of react-shadcn-ui § Component workshop, which keeps a pointer here rather than a copy.

The Iron Law

ONE CONCEPT PER STORY. NEVER A "SizesAndVariants" STORY.
EVERY COMPONENT EXPORT AND EVERY STORY CARRIES A JSDoc @summary.
A STORY THAT SHOWS AN ANTI-PATTERN IS TAGGED `!manifest` OR THE AGENT LEARNS FROM IT.
STORIES RUN. A STORY NOBODY RUNS IS A SCREENSHOT WITH EXTRA STEPS.

When to use

A shared component library exists or is being started, and one of: stories are being added, an agent needs an inventory of what the library already offers, an a11y regression should be caught in isolation rather than on a screen, or a Storybook MCP channel is available and nobody has decided whether to use it.

Skip it for a handful of one-off components with a single consumer — the setup and upkeep outweigh the return, and that judgement belongs to the reader rather than to this skill.

The story set — one concept per story

The state-coverage rows every reusable component owes become story names: Default, Loading, Empty, Error, Disabled, Dark. One concept each.

A combined story — the canonical anti-pattern is SizesAndVariants — fails at both jobs it has: a human cannot tell which knob caused what, and an agent reading it cannot learn a single prop's effect because every value is co-present. Split it, one axis per story (Storybook's own guidance on writing effective stories).

Stories render under the same semantic tokens as the app and the .dark class; a hardcoded preview theme makes the workshop lie about what the component looks like in place.

JSDoc @summary is required, and the reason is mechanical

The manifest an agent reads truncates descriptions. A component whose summary is a paragraph arrives as a fragment, and the agent then infers the rest. So:

/** @summary A single-action button. Owns its own focus ring; never wrap in an anchor. */
export const Button = …

/** @summary Disabled — the click handler is not attached, not merely ignored. */
export const Disabled: StoryObj<typeof Button> = …

One sentence, front-loaded with the fact that changes a caller's decision.

Before authoring — review what the library already has

The first step is not a story, it is an inventory. A library large enough to want a workshop is large enough that the component being asked for already exists under another name, and a second Badge is the failure this skill's own § Do NOT is trying to prevent elsewhere.

Read the existing stories — via the MCP channel below when it is available, by reading the files otherwise — and only then decide whether anything needs writing.

Procedure

1. Inspect the existing story set before authoring anything. Read what the library already has — via the MCP channel below when it is available, otherwise by reading the story files — and check the component against it by name and by shape.
   • Source of truth: the story files, or list-all-documentation over a running Storybook.
   • Verify: the component you are about to write does not already exist under another name.
2. One story per concept, named from the state set above.
   • Verify: no story name joins two axes with And.
3. Write the @summary on the export and on each story.
   • Verify: every export in the file has one, and each is a single sentence.
4. Tag what must not be learned from — see § Do NOT.
   • Verify: every anti-pattern or deprecated story carries tags: ['!manifest'].
5. Run them — § Validate.
   • Verify: the run reports pass/fail per story, and a11y findings land in the shape below.

Validate — stories are tests

Run the project's story test command (the Vitest addon's storybook test, or whatever package.json declares — read it, do not assume a name), then read the a11y result.

Write findings into state.ui_review.a11y in the shape react-shadcn-ui § Review pass already defines:

{violations: [{rule, selector, severity}, …], severity_floor?, accepted_violations?}

Use that shape exactly. The engine de-duplicates on it, so a finding written in a different shape is not a differently-formatted finding — it is a finding the engine counts twice.

Browser tooling stays a consumer dependency, the same posture as react-shadcn-ui: this package installs no browser and runs none. Absent the tooling, say the a11y half did not run rather than reporting zero violations — an unrun check and a clean check produce the same number and mean opposite things.

One finding is decidable without a browser, and it ships beside this skill: scripts/story_contrast_floor.ts computes the WCAG 2.1 contrast ratio between two colours a story declares in its own args and emits the same (rule, selector, severity) shape. It is not axe and not a substitute for § Validate — it sees no rendered page, so role, focus, and computed-style defects are all outside it, and a colour arriving through a token indirection is invisible to it. It exists because "we cannot run axe here" is not a reason to check nothing, and a declared colour pair is decidable from the file.

Security constraints

scripts/story_contrast_floor.ts reads story files and computes arithmetic. No network, no subprocess, no writes, and it never evaluates the story it reads — it matches declared literals with a regex rather than importing the module, so running it over an untrusted repository executes none of that repository's code. Importing a story to inspect its args would run that file, which is the one thing a static checker must not start doing.

MCP path — opt-in channel, never a dependency

"Opt-in" is about the agent connecting, not about installing. A 2026-08-24 npx storybook@latest init --yes scaffold ships @storybook/addon-mcp and @storybook/addon-a11y in devDependencies by default — recorded verbatim in tests/fixtures/stack/storybook-current/, which is also the only source any Storybook major stated here may come from (storybook@^10.5.10). So the addon usually already exists; what stays optional is whether an agent reaches a running instance. The same scaffold prints "installed but is not entirely set up yet", so its presence is not evidence the channel works.

When the project has @storybook/addon-mcp and a running Storybook, existing-ui-audit prefers the live tools — list-all-documentation, then get-documentation for the components that matter — over the hand-read inventory. The live read wins; the file read is the fallback, and the fallback is never removed: an agent that cannot reach a running Storybook must still be able to inventory the library.

React-only while in preview. Storybook's own MCP FAQ (docs 10.5) states the documentation toolset supports React only during preview, so Vue, Angular, and Web Components take the file-read path. Stated here rather than discovered at runtime.

Two operative rules, restated from Storybook's suggested agent instructions rather than copied verbatim:

• Never use an undocumented prop. If the manifest does not carry it, it is not part of the component's surface — reading it out of the implementation is how a private prop becomes a de-facto API.
• Fetch the story instructions before writing a story. The project's own conventions live there; writing first and reconciling later produces a story that matches nothing.

Output format

1. Name the inventory source used — MCP or file read — and why.
2. List the stories authored or changed, one line each, with their concept.
3. Report the story-test result, and the a11y findings in the (rule, selector, severity) shape.
4. State explicitly what did not run (no browser tooling, no running Storybook, non-React renderer).

Gotchas

• SizesAndVariants looks efficient and destroys both jobs — a human cannot attribute the effect, and an agent cannot learn a single prop from it.
• A truncated description reads as a complete one. The manifest cuts the tail without marking it, so a paragraph-long summary arrives as a confident fragment.
• A stale story is worse than no story. It props-drills values the component no longer accepts and documents an API that does not exist; keep stories beside the component and change them in the same commit.
• An unrun a11y check reports zero violations — the same number a clean run reports. Say which one happened.
• The MCP channel disappearing is normal, not an error: no running Storybook is the fallback's whole purpose.

Do NOT

• Do NOT combine two axes in one story.
• Do NOT ship a component export or a story without a @summary.
• Do NOT leave an anti-pattern or deprecated story untagged: it carries tags: ['!manifest'] so it is excluded from the manifest and the agent never learns from it (Storybook's own tag mechanism for curating what the manifest exposes).
• Do NOT hardcode a preview theme in a story.
• Do NOT make the MCP channel required, and do NOT remove the file-read fallback.
• Do NOT report zero a11y violations when the a11y tooling did not run.

See also

• react-shadcn-ui — the React stack lane, and the (rule, selector, severity) shape § Validate writes into.
• existing-ui-audit — the inventory the MCP path accelerates.
• js-library-packaging — the package around the workshop.
• accessibility-auditor — the WCAG depth behind the a11y half.
• fe-design § Component Architecture — the stack-agnostic isolate-and-document principle.