MCP Server Builder
anthropics/skills
Guides the design and implementation of Model Context Protocol servers in TypeScript or Python, from tool naming and error messages to evaluation.
Design Video.js TypeScript APIs. An agent skill from videojs/video.js.
Custom licenceAuto-check passed
Install Design API
$ npx skills add videojs/video.js --skill design-api -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install videojs/video.js design-api --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/videojs/video.js.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.agents/skills/design-api .claude/skills/design-api && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "design-api" agent skill from https://github.com/videojs/video.js/tree/main/.agents/skills/design-api into .claude/skills/design-api/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "design-api", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/videojs/video.js/tree/main/.agents/skills/design-apiType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add videojs/video.js --skill design-api -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install videojs/video.js design-api --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/videojs/video.js.git skills-src && mkdir -p .agents/skills && cp -r skills-src/.agents/skills/design-api .agents/skills/design-api && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "design-api" agent skill from https://github.com/videojs/video.js/tree/main/.agents/skills/design-api into .agents/skills/design-api/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "design-api", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add videojs/video.js --skill design-api -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install videojs/video.js design-api --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/videojs/video.js.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/.agents/skills/design-api .cursor/skills/design-api && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "design-api" agent skill from https://github.com/videojs/video.js/tree/main/.agents/skills/design-api into .cursor/skills/design-api/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "design-api", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/videojs/video.js.git --path .agents/skills/design-api--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add videojs/video.js --skill design-api -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install videojs/video.js design-api --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/videojs/video.js.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/.agents/skills/design-api .gemini/skills/design-api && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "design-api" agent skill from https://github.com/videojs/video.js/tree/main/.agents/skills/design-api into .gemini/skills/design-api/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "design-api", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install videojs/video.js design-apiInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add videojs/video.js --skill design-api -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/videojs/video.js.git skills-src && mkdir -p .github/skills && cp -r skills-src/.agents/skills/design-api .github/skills/design-api && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "design-api" agent skill from https://github.com/videojs/video.js/tree/main/.agents/skills/design-api into .github/skills/design-api/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "design-api", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add videojs/video.js --skill design-api -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install videojs/video.js design-api --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/videojs/video.js.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/.agents/skills/design-api .opencode/skills/design-api && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "design-api" agent skill from https://github.com/videojs/video.js/tree/main/.agents/skills/design-api into .opencode/skills/design-api/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "design-api", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
design-api- GitHub stars
- 40k
- Token cost
- ~378 tokens
- SKILL.md length
- 164 words
- Files
- 8 (incl. references)
- Skills in repo
- 38
- Repo updated
- First seen
- Licence
- Custom licence
At a glance
Design Video.js TypeScript APIs. An agent skill from videojs/video.js.
- Works in 5 steps: Correct observable behavior → Type safety and useful inference → A small, coherent concept set → …
- Extension points
- SKILL.md covers Default priorities, Load references conditionally and Example
- Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
What it does
Design API is an agent skill from videojs/video.js. Design Video.js TypeScript APIs. Use for public shape, inference, state, extension points, middleware, composition, or ergonomics.
Its SKILL.md is about 380 tokens, which your agent loads only when the skill is triggered. The skill folder holds 8 other files, including reference files (for example `references/anti-patterns.md`, `references/extensibility.md` and `references/libraries.md`).
It works with TypeScript. The repository describes itself as: Video.js v10 - open source media player framework for HTML and React.
When your agent uses it
- Extension points
Example prompts
- “/design-api”
Workflow steps
5 steps, taken from the first numbered list in SKILL.md.
- Correct observable behavior
- Type safety and useful inference
- A small, coherent concept set
- Consistency with adjacent Video.js APIs
- Composable escape hatches and tree-shakable output
What it can do on your machine
Read from SKILL.md and the folder at commit 74cf8cd. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md.
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Design API loads about 378 tokens when it runs, and up to ~14k if it reads all its reference files. Until then it costs about 35 tokens; SKILL.md has 164 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
SKILL.md
Its licence (Custom licence) doesn't allow us to republish the file, so here is its outline and opening line. It has 164 words (~378 tokens).
“Inspect the current call sites, types, tests, exports, and relevant design records before applying general guidance. Existing local contracts beat generic patterns.”
- name
- design-api
Files
SKILL.md and 7 other files (references) in .agents/skills/design-api of videojs/video.js.
- SKILL.md
- references/anti-patterns.md
- references/extensibility.md
- references/libraries.md
- references/principles.md
- references/state.md
- references/typescript.md
- references/voices.md
Open the folder on GitHubat commit 74cf8cd
Used in 1 other repository
We found 1 copy of this SKILL.md (exact, near-identical or edited) in other folders. This page covers the copy in videojs/video.js, which our catalogue first saw on October 7, 2026.
Compare with similar skills
Design API next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Design API this skillvideojs/video.js | 40k | — | ~378 | Automated safety check: Pass | Custom licence | |
| MCP Server Builderanthropics/skills | 180k | 64 repos | ~2.3k | Automated safety check: Pass | Apache-2.0 | |
| Web Artifacts Builderanthropics/skills | 180k | 41 repos | ~769 | Automated safety check: Pass | Apache-2.0 | |
| Typescript Advanced Typesrolling-scopes/rsschool-app | 10k | 25 repos | ~4.2k | Automated safety check: Pass | MPL-2.0 | |
| Code Review ChecklistshareAI-lab/learn-claude-code | 78k | 5 repos | ~1.1k | Automated safety check: Pass | MIT | |
| MCP Server BuildershareAI-lab/learn-claude-code | 78k | 5 repos | ~1.2k | Automated safety check: Pass | MIT |
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- Official
- Official
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Import, merge, or combine repositories into an Nx workspace using nx import.
More from videojs/video.js
All 38 skills in this repoCommit PR
videojs/video.js
Commit, push, and create or update a Video.js pull request. An agent skill from videojs/video.js.
Maintain Tests
videojs/video.js
Gate and audit test value. An agent skill from videojs/video.js.
Write API Reference
videojs/video.js
Write generated Video.js API reference pages. An agent skill from videojs/video.js.
Write Docs
videojs/video.js
Write Video.js guides, concepts, READMEs, and JSDoc. An agent skill from videojs/video.js.
Write Locale Translations
videojs/video.js
Translate or audit the values in a Video.js locale pack. An agent skill from videojs/video.js.
Change Spf Behavior
videojs/video.js
Change SPF playback-engine behaviors. An agent skill from videojs/video.js.
Related
Works with
Questions about Design API
What does Design API do?
Design Video.js TypeScript APIs. An agent skill from videojs/video.js. js.js TypeScript APIs.
When should I use Design API?
Design API fits situations like: extension points.
How do I install Design API in Claude Code?
Run `npx skills add videojs/video.js --skill design-api -a claude-code`. Or copy the skill folder (.agents/skills/design-api in videojs/video.js) into .claude/skills/design-api in your project. Claude Code loads it when a task matches its description.
How do I install Design API in Codex?
Run `npx skills add videojs/video.js --skill design-api -a codex`. Or copy the skill folder (.agents/skills/design-api in videojs/video.js) into .agents/skills/design-api in your project. Codex loads it when a task matches its description.
Can I use Design API in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add videojs/video.js --skill design-api -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/design-api, .gemini/skills/design-api, .github/skills/design-api and .opencode/skills/design-api in your project.
What does Design API need to run?
SKILL.md names no scripts, command-line tools or credentials: Design API is instructions for the agent only.
Does Design API access the network?
SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.
Is Design API safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does Design API use?
Design API has a licence file (the repository's licence) that doesn't match a standard licence. Read it on GitHub before reusing the skill.
How many tokens does Design API use?
About 378 tokens (SKILL.md is roughly 1.5k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 13k tokens, read only when the agent opens those files.
What are the alternatives to Design API?
Skills that share tags, products or a category with Design API: MCP Server Builder (anthropics/skills, 180k stars), Web Artifacts Builder (anthropics/skills, 180k stars), Typescript Advanced Types (rolling-scopes/rsschool-app, 10k stars) and Code Review Checklist (shareAI-lab/learn-claude-code, 78k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Design API?
videojs (a GitHub organization) maintains it in videojs/video.js, which has 39,909 GitHub stars. The repository holds 38 skills in this directory. The repository was last updated on October 8, 2026.
Source: videojs/video.js on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.