utilities

name	utilities
description	Use when the developer wants Tailwind-style atomic CSS utility classes for fpkit/acss — add, list, tune spacing/breakpoints, or regenerate the token-bridge.
allowed-tools	AskUserQuestion, Bash, Edit, Glob, Grep, Read, Write
metadata	{"version":"0.2.0"}

utilities

Atomic-CSS utility-class generation and management for fpkit/acss projects. Routes between four flows depending on which slash command was invoked. Bundles a single utilities.css (full atomic suite) and a token-bridge.css (acss-kit ↔ fpkit alias layer).

Naming and class catalogue: see references/utility-catalogue.md and references/naming-convention.md. Breakpoints and responsive syntax: see references/breakpoints.md. Token bridge mapping: see references/token-bridge.md.

---

Source-of-truth

The plugin's atomic suite is generated from assets/utilities/utilities.tokens.json. Edits to that file (manual or via /utility-tune) should be followed by python3 ${CLAUDE_PLUGIN_ROOT}/scripts/generate_utilities.py --tokens ${CLAUDE_PLUGIN_ROOT}/assets/utilities/utilities.tokens.json --out-dir ${CLAUDE_PLUGIN_ROOT}/assets/utilities/ to regenerate the committed bundle.

The committed assets/utilities/utilities.css and assets/utilities/<family>.css partials are the canonical artifacts — tests/run.sh enforces idempotency by regenerating and diffing.

---

Step 0 — Exit plan mode

Applies to every flow below (/utility-add, /utility-list, /utility-tune, /utility-bridge). If the session is in plan mode, call ExitPlanMode before proceeding — the write-bearing flows each shell out to a different subset of the bundled scripts:

• /utility-add runs detect_utility_target.py and copies the prebuilt utilities.css (and token-bridge.css unless --no-bridge) into the project. When acss-kit is installed alongside, it also calls the cross-plugin detect_stack.py + verify_integration.py from acss-kit; when acss-kit is absent, those two are skipped with a warning.
• /utility-bridge writes token-bridge.css and runs validate_utilities.py.
• /utility-tune edits assets/utilities.tokens.json, regenerates the bundle via generate_utilities.py, and validates via validate_utilities.py.

Plan mode blocks every one of those Write/Edit/Bash calls.

/utility-list is read-only and stays safe under plan mode — no Write/Edit/Bash and no need to exit. Only call ExitPlanMode when the user pivots to one of the write-bearing flows above.

Stay in plan mode only when it is absolutely necessary — i.e. the user explicitly asked for a preview ("show me which families would land", "don't write the bundle yet"). In that case, narrate the file list and bundle size without invoking Write/Edit/Bash, and wait for approval before re-entering this skill.

---

/utility-add [--target=<dir>] [--families=<list>] [--no-bridge]

Purpose: Copy utilities.css (and token-bridge.css unless --no-bridge) into the user's React project.

Workflow

1. Run ${CLAUDE_PLUGIN_ROOT}/scripts/detect_utility_target.py. Capture JSON.
   • source: "configured" or "default" → use utilitiesDir from result.
   • source: "none" (exit 1) → halt with the reasons array; suggest --target=<dir>.
2. Run ${CLAUDE_PLUGIN_ROOT}/scripts/detect_stack.py <project_root> to classify framework + entrypoint. If the cross-plugin path is unavailable (acss-kit not installed), skip with a warning and the verification step (8) will be a no-op. When detection succeeds, merge the result into .acss-target.json under a stack key.
3. If --target=<dir> was passed, override the detected utilitiesDir.
4. If --families=<list> was passed:
   • Parse comma-separated family names. Validate against assets/utilities/.
   • Concatenate the requested family partials in canonical order (the order in FAMILY_ORDER in generate_utilities.py) plus the bundle header.
   • Write the concatenated result to <target>/utilities.css.
5. Otherwise copy the prebuilt ${CLAUDE_PLUGIN_ROOT}/assets/utilities/utilities.css verbatim to <target>/utilities.css.
6. Unless --no-bridge, copy ${CLAUDE_PLUGIN_ROOT}/assets/utilities/token-bridge.css to <target>/token-bridge.css.
7. Print the import snippet:

   import "./styles/token-bridge.css";   // first
   import "./styles/utilities.css";       // then
   

8. Print a summary: files written, total bundle size in KB, families included.
9. Run ${CLAUDE_PLUGIN_ROOT}/scripts/verify_integration.py <project_root> (skip if acss-kit was not present in step 2). Exit 0 → done. Exit 1 → print the reasons array as a numbered fix-up list. Do not auto-edit the entrypoint.

References to load

• references/utility-catalogue.md — full family list, every class, every CSS custom property referenced.
• references/token-bridge.md — required when --no-bridge is not set, so the assistant can explain the bridge's role.

---

/utility-list [family]

Purpose: Read-only catalogue printer. No side effects.

Workflow

/utility-list (no arguments)

1. Read assets/utilities.tokens.json from ${CLAUDE_PLUGIN_ROOT}/.
2. Print every family from families with its enabled and responsive status.
3. Print the spacing scale and breakpoints inline, since they parameterize multiple families.
4. Suggest /utility-list <family> for class-level detail.

/utility-list <family>

1. Look up the family's per-family partial at ${CLAUDE_PLUGIN_ROOT}/assets/utilities/<family>.css.
2. Print every selector and the property it sets (one line per class). For families with token references, also print the var() chain — e.g. .bg-error → var(--color-error, transparent) → resolved via token-bridge.css to var(--color-danger, #dc2626).
3. Print the count of classes and the file size.

References to load

• references/utility-catalogue.md

---

/utility-tune <natural-language>

Purpose: Adjust the spacing baseline, breakpoints, or family-enable map via natural language. Edits assets/utilities.tokens.json, regenerates the bundle, runs the validator.

Examples

Phrase	Effect on tokens.json
"use a 4px spacing baseline"	spacing.baseline = "0.25rem"
"use an 8px spacing baseline"	spacing.baseline = "0.5rem"
"add an xs breakpoint at 20rem"	breakpoints.xs = "20rem" (validator extends --prefixes)
"disable shadow utilities"	families.shadow.enabled = false
"drop responsive variants from spacing"	families.spacing.responsive = false
"add a 'soft' radius value at 1rem"	radius.soft = "1rem"

Workflow

1. Parse the natural-language request into one or more concrete edits to utilities.tokens.json. If the intent is ambiguous, ask one clarifying question via AskUserQuestion before making edits.
2. Read ${CLAUDE_PLUGIN_ROOT}/assets/utilities/utilities.tokens.json. Apply the edits in memory.
3. Write the updated tokens back to disk (preserving JSON key order where possible — use a stable serializer).
4. Run python3 ${CLAUDE_PLUGIN_ROOT}/scripts/generate_utilities.py --tokens ${CLAUDE_PLUGIN_ROOT}/assets/utilities/utilities.tokens.json --out-dir ${CLAUDE_PLUGIN_ROOT}/assets/utilities/.
5. Run python3 ${CLAUDE_PLUGIN_ROOT}/scripts/validate_utilities.py ${CLAUDE_PLUGIN_ROOT}/assets/.
   • On ok: false, print the reasons array and revert the tokens.json edit. The committed bundle should never go out of contract.
6. Print a summary: which fields changed, new bundle size, number of classes added/removed.

References to load

• references/utility-catalogue.md, references/breakpoints.md, references/naming-convention.md

---

/utility-bridge [--theme=<file>]

Purpose: Regenerate token-bridge.css aliases against the user's active acss-kit theme. Always emits both :root and [data-theme="dark"] blocks.

Workflow

1. If --theme=<file> was passed, use that as the source theme. Otherwise look in priority order:
   • <projectRoot>/src/styles/theme/light.css and dark.css
   • <projectRoot>/src/styles/theme/*.css
   • If nothing found, fall back to the bundled ${CLAUDE_PLUGIN_ROOT}/assets/utilities/token-bridge.css defaults and warn the user.
2. Read the source theme(s) and extract the --color-danger, --color-primary, --color-success, etc. values for both light and dark modes.
3. Build the bridge file with the fpkit-style aliases — --color-error: var(--color-danger, <resolved-hex>), --color-error-bg: color-mix(in oklch, var(--color-danger, <hex>) 12%, var(--color-background, <bg-hex>)), and so on.
4. Always emit both blocks; if the source theme has no [data-theme="dark"], fall back to the same values for dark (and warn).
5. Write to <projectRoot>/<utilitiesDir>/token-bridge.css (default src/styles/token-bridge.css).
6. Run python3 ${CLAUDE_PLUGIN_ROOT}/scripts/validate_utilities.py <bridge-file> to enforce parity.
7. Print a summary: which roles were aliased, which had explicit fallbacks, dark-mode parity status.

References to load

• references/token-bridge.md — full alias mapping and rationale.

---

Quality gates (post-flow)

Every flow ends with a contract check. The plugin's hooks and tests/run.sh enforce these automatically; the skill should run them locally too:

• Bundle integrity — python3 ${CLAUDE_PLUGIN_ROOT}/scripts/validate_utilities.py ${CLAUDE_PLUGIN_ROOT}/assets/ exits 0.
• Idempotency — regenerating from utilities.tokens.json produces the same bytes as the committed utilities.css.
• Bridge parity — every alias in :root is also defined in [data-theme="dark"].

If any of these fail, the user-visible flow halts and the assistant reports the reasons array verbatim.

---

Out of scope (deferred to v2)

• Scan-and-emit (JIT / purge) — the bundle is full by default; --families provides static filtering.
• Auto-trigger on natural language ("make this padded") — /utility-tune is the explicit invocation.
• Theme-mode utilities (dark:bg-primary, etc.) — fpkit doesn't ship these upstream.
• Generating React components — acss-kit owns components.