v10

Implement a feature documented in the SPF feature registry. Consumes a feature doc at internal/design/spf/features/<name>.md and produces the engine-side code: new behaviors, updates to existing behaviors, media-layer / network-layer primitives, and tests. The implementation analog of /spf-document-feature (which produces the doc; this consumes it). Walks through resolving the doc's open questions before coding, maps phases to discrete chunks, applies the SPF conventions catalog, routes to downstream skills (/spf-create-behavior, /spf-update-behavior, /refactor-behavior) per chunk shape, and updates the feature doc's Status / Implementation surface / Verification sections as code lands. Triggers: "implement feature", "implement SPF feature", "build feature", "code feature", "scope feature implementation", "implement <feature-name>".

Create a new SPF behavior with conventions-aligned shape. Walks through purpose articulation (carries /refactor-behavior's purpose-first discipline), signal type choice, slot map design, composition placement, cleanup pattern selection, test placement, and engine wiring. Distinct from /refactor-behavior (which modifies an existing behavior preserving its purpose) and /spf-update-behavior (which modifies an existing behavior whose purpose is changing). Triggers: "create behavior", "new behavior", "create SPF behavior", "add behavior", "scaffold behavior", "new SPF behavior".

Produce or update an entry in the SPF use-case-composition registry at internal/design/spf/use-cases/. Triangulates context from multiple sources (Notion, GitHub, pasted writeups, existing use-case docs, constituent feature docs, codebase), grounds the use case in the four composition mechanisms (subtract / add / alternative-impl / alternative-default-config), applies use-case-specific cross-cutting concern checks, drafts the doc at the appropriate definition depth, and cascades narrow updates to constituent feature docs and sibling use cases. Triggers: "document use case", "register use case", "use case doc", "update use case doc", "deepen use-case stub", "new SPF use case", "use case composition", "draft use-case registry entry", "new use case composition".

Implement a use-case composition documented in the SPF use-case-composition registry. Consumes a use-case doc at internal/design/spf/use-cases/<name>.md and produces the engine-side code: a variant engine factory, a parallel adapter, composition wiring, use-case-specific behaviors (if any), and tests. The implementation analog of /spf-document-use-case (which produces the doc; this consumes it). Walks through disambiguation + routing (verify the request is actually a use case, check constituent-feature implementation status), resolves the doc's open questions with the user, maps phases to chunks, routes to downstream skills (/spf-implement-feature for unimplemented constituents, /spf-create-behavior, /spf-update-behavior, /refactor-behavior), and updates both the use-case doc and constituent feature docs as code lands. Treats the use-case doc as a starting point for planning, not a hardened specification. Triggers: "implement use case", "implement SPF use case", "implement use-case composition", "build use ca

Update an existing SPF behavior whose purpose is changing or expanding. Distinct from /refactor-behavior, which preserves purpose — this skill handles cases where the behavior gains new responsibility (new state slot to react to, new lifecycle phase, new constraint, new code path). Carries /refactor-behavior's purpose-first discipline applied to the *purpose change*. Triggers: "update behavior", "extend behavior", "modify behavior", "change behavior purpose", "expand behavior responsibility".

Produce or update an entry in the SPF feature registry at internal/design/spf/features/. Triangulates context from multiple sources (Notion, GitHub, pasted writeups, existing feature docs, codebase), grounds the feature in the cluster heuristics, applies cross-cutting concern checks, drafts the doc at the appropriate definition depth, and cascades narrow updates to related feature docs. Triggers: "document feature", "register feature", "feature doc", "update feature doc", "deepen feature stub", "draft feature registry entry", "new SPF feature".

Merge two SPF behaviors into one with cleaned-shape-first discipline. Forces per-side standalone analysis and an explicit complexity-driven direction declaration before any combining happens — avoids the "relocated mess" failure mode where the merge anchors on the current merged-file shape rather than the cleaned per-side shapes. Use after /refactor-behavior's decomposition check has concluded "merge," or to redo a merge that landed without the discipline. Triggers: "merge behaviors", "merge these behaviors", "combine behaviors", "redo merge", "merge X into Y".

Refactor an existing SPF behavior using purpose-first discipline. Forces articulation of the behavior's purpose and business rules before code analysis, then maps to the documented patterns in internal/design/spf/conventions/. Triggers: "refactor behavior", "refactor this behavior", "clean up behavior", "apply conventions to behavior", "review behavior for refactor".

Split one SPF behavior into N with axis-declared, constraints-audited discipline. Forces explicit axis declaration (per-type horizontal vs. per-concern vertical) and a cross-boundary constraint audit before the split lands — avoids the failure mode where an apparent per-type-friendly behavior ships a split that quietly drops a cross-type ordering invariant the merged code was enforcing. Use after /refactor-behavior's decomposition check has concluded "split," or when you've already noticed a behavior wants splitting. Triggers: "split this behavior", "split into per-type", "extract per-type behaviors", "convert to per-type variants", "split behavior".

Update CLAUDE.md and skills when introducing new patterns or conventions. Triggers: "update claude", "update skills", "new pattern", "add convention".

Migrate vanilla CSS, CSS modules, SCSS, or styled-component styles to Tailwind v4 utilities. Prefer @theme-backed tokens and semantic utilities; document arbitrary values and parity gaps. For audits, load review/workflow.md. Triggers: "CSS to Tailwind", "migrate to Tailwind", "tailwind migration", "styled-components to Tailwind", "SCSS to Tailwind", "review Tailwind classes", "tailwind parity".

Write and review documentation for Video.js 10 — site pages, READMEs, and JSDoc. Use for writing concept pages, how-to guides, package READMEs, and inline API docs. Component reference pages use the `api-reference` skill instead. Triggers: "write docs", "create guide", "review docs", "audit documentation", "write README", "JSDoc", "inline docs".

Create GitHub issues with consistent title casing, type prefixes, and body structure for the videojs/v10 repo. Use when filing bugs, requesting features, or creating any ticket/issue. Triggers: "create issue", "new issue", "file issue", "open issue", "file bug", "request feature", "create ticket", "new ticket", "file ticket", "open ticket".

Write Design Docs for Video.js 10. Use for architectural decisions, component specs, feature designs, and internal patterns you own. Triggers: "write design doc", "create design", "component spec", "feature design", "document decision".

Commit all changes and create or update a PR following project conventions. Triggers: "commit and pr", "push changes", "create pull request".

Review changes in the current Git branch and suggest improvements. Triggers: "review branch", "review changes", "code review".

Review and implement accessibility patterns for UI components following WAI-ARIA and WCAG 2.1. Use when auditing code for a11y issues, implementing accessible controls, adding ARIA attributes, fixing keyboard navigation, handling focus management, building screen reader support, or implementing media player accessibility. Triggers on "accessibility review", "a11y", "ARIA", "keyboard navigation", "screen reader", "focus management", "WCAG", "captions", "live region".

Build accessible, headless UI components with modern architecture patterns. Use when creating component libraries, design systems, or reusable UI primitives. Handles compound components, state management, accessibility, styling hooks, and API design. Includes HTML (controllers, ReactiveElement) and React (hooks, context) patterns. Triggers: "create component", "component pattern", "compound component", "headless component".

Scaffold API reference documentation for Video.js 10 components and utility APIs. Validates the api-docs-builder output, checks design docs and linked PRs for context, creates the MDX reference page with anatomy, prose sections, demos, and the ComponentReference/UtilReference component. Triggers: "api reference", "reference page", "scaffold api docs", "add api docs", "component reference", "util reference", "hook reference".

API design and developer experience for TypeScript libraries. Use when designing APIs, reviewing architecture, evaluating DX, or checking ergonomics. Covers extensibility, progressive disclosure, type inference, state patterns, and composition. For review, load review/workflow.md. Triggers: "design API", "review API", "check DX", "is this ergonomic", "review architecture", "middleware design", "how does this feel".

Create new skills for Claude agents. Use when adding specialized knowledge, workflows, or commands. Guides through structure, frontmatter, and conventions. Triggers: "create skill", "new skill", "add skill", "write skill".

Analyze GitHub issues and create a comprehensive plan to solve them. Triggers: "analyze issue", "plan issue", "investigate issue".

Write RFCs for Video.js 10. Use for proposals that need buy-in — public API changes, product direction, user-facing DX, core architecture. Triggers: "write RFC", "create RFC", "propose", "need buy-in", "architecture proposal".

Git workflow conventions for Video.js 10. Commit messages, PR descriptions, branch naming, and scope inference. Triggers: "commit", "push", "create PR", "conventional commit", "branch name", "open pull request".