Agent skill · Anthropic

Claude API skill for Claude Code, Codex and Cursor

Reference for building on the Claude API and Anthropic SDKs: models, tool use, streaming, caching, pricing.

Officialname: claude-api★ 184k (repo)pushed 2026-10-09See repoSKILL.md on GitHubchecked 2026-11-07

What it does, in the publisher's words

Reference for the Claude API / Anthropic SDK — model ids, pricing, params, streaming, tool use, MCP, agents, caching, token counting, model migration.

The description field of the SKILL.md. The agent reads only this at startup and decides from it when to load the full skill.

Install Claude API

The skills CLI copies the skill into the folder of each agent you pick (Claude Code, Codex, Cursor, Copilot, Gemini CLI, OpenCode, Windsurf...). Add -g for all projects. Needs Node.js 22.20+. docs

npx skills add anthropics/skills --skill claude-api

This repo is a plugin marketplace. Inside Claude Code, add it and install the plugin that holds the skill (document-skills, example-skills, claude-api, academy-guide...), or copy only this skill into ~/.claude/skills. docs

/plugin marketplace add anthropics/skills
/plugin install <plugin>@anthropic-agent-skills

# or only this skill:
npx skills add anthropics/skills --skill claude-api -a claude-code

Download the skill folder, zip it, then Customize > Skills > + > Create skill > Upload a skill. Code execution must be on (Settings > Capabilities). docs

git clone --depth 1 https://github.com/anthropics/skills.git /tmp/claude-api-src
cp -r /tmp/claude-api-src/skills/claude-api ./claude-api
zip -r claude-api.zip claude-api

Codex reads skills from .agents/skills in the repo or ~/.agents/skills. Type $ in Codex to use one. docs

npx skills add anthropics/skills --skill claude-api -a codex

gh skill (GitHub CLI 2.90+, preview) installs it for Copilot in VS Code, the CLI and the cloud agent. Copilot also reads .github/skills and ~/.copilot/skills. docs

gh skill install anthropics/skills claude-api

Cursor reads .cursor/skills, .agents/skills and ~/.cursor/skills (and .claude/skills). It does not install loose skills from a GitHub URL, so copy it in. docs

npx skills add anthropics/skills --skill claude-api -a cursor

Installs from the GitHub repo; --path picks this skill out of the repo. Default scope is user (all projects). docs

gemini skills install https://github.com/anthropics/skills.git --path skills/claude-api

OpenCode reads .opencode/skills, ~/.config/opencode/skills and the Claude and .agents folders. docs

npx skills add anthropics/skills --skill claude-api -a opencode

Windsurf (now Devin Desktop) reads .devin/skills, .windsurf/skills and ~/.codeium/windsurf/skills. docs

npx skills add anthropics/skills --skill claude-api -a windsurf

Works with

Claude Code, Claude.ai and Claude Desktop, Codex, GitHub Copilot, Cursor, Gemini CLI, OpenCode, Windsurf and other agents that read the open Agent Skills format.

Bundles 2 JavaScript scripts the agent can run, so it needs JavaScript on the machine. In the Claude apps, code execution must be on.

What's in the SKILL.md

38 sections

Before You Start
Output Requirement
Defaults
Warning: API Drift - Your Training Prior May Be Stale
Subcommands
Language Detection
Language-Specific Feature Support
Which Surface Should I Use?
Building an Agent: Four Approaches
Should I Build an Agent?
Architecture
Current Models (cached: 2026-10-06)
Claude Fable 5.1 (claude-fable-5-1) - most capable widely released model
Claude Opus 5.5 (claude-opus-5-5) - the current Opus and the default model
Claude Sonnet 5.5 (claude-sonnet-5-5) - the current Sonnet: speed and capability for everyday coding, agent, and enterprise work (Claude Opus 5.5 stays the default)
Claude Haiku 5.5 (claude-haiku-5-5) - the current Haiku
Authentication (Quick Reference)
Thinking & Effort (Quick Reference)
Compaction (Quick Reference)
Prompt Caching (Quick Reference)
Fast Mode (Quick Reference)
Task Budgets (Quick Reference)
Provider Clients (Quick Reference)
Amazon Bedrock
+ 14 more

Bundled files

LICENSE.txt
csharp/claude-api/README.md
csharp/claude-api/batches.md
csharp/claude-api/files-api.md
csharp/claude-api/streaming.md
csharp/claude-api/tool-use.md
curl/examples.md
curl/managed-agents.md
go/claude-api/README.md
go/claude-api/files-api.md
go/claude-api/streaming.md
go/claude-api/tool-use.md
go/managed-agents/README.md
java/claude-api/README.md
java/claude-api/files-api.md
java/claude-api/streaming.md
java/claude-api/tool-use.md
java/managed-agents/README.md
php/claude-api/README.md
php/claude-api/batches.md
+ 75 more

Loaded only when the instructions point to them.

Facts

Skill name: claude-api
Publisher: Anthropic (official)
Repo: anthropics/skills
License: Complete terms in LICENSE.txt
SKILL.md size: 14,422 words, 608 lines
Bundled files: 95, 2 scripts (JavaScript), 57 docs
Repo stars: 184k (as of 2026-10-24)
SKILL.md checked: 2026-11-07

More skills from anthropics/skills

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Frontend Design: Steers UI work toward deliberate visual direction and typography instead of generic template looks.
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PDF: Extracts text and tables, merges, splits, fills forms and creates PDF files.
PowerPoint (PPTX): Builds, reads and edits PowerPoint decks and templates, including layouts and speaker notes.
Skill Creator: Helps write new skills, refine existing ones and test how well they trigger and perform.
Slack GIF Creator: Makes small animated GIFs sized and validated for Slack's emoji and message limits.
Web Artifacts Builder: Builds multi-component HTML artifacts with React, Tailwind and shadcn/ui, bundled into one file.
Web App Testing: Uses Playwright to drive a local web app, check behavior, read console logs and take screenshots.
Excel Spreadsheets (XLSX): Opens, cleans, edits and creates spreadsheets (.xlsx, .csv), including formulas and charts.

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FAQ

What does the claude-api skill do?+

Reference for building on the Claude API and Anthropic SDKs: models, tool use, streaming, caching, pricing. In its own SKILL.md, Anthropic describes it as: "Reference for the Claude API / Anthropic SDK — model ids, pricing, params, streaming, tool use, MCP, agents, caching, token counting, model migration."

How do I install the claude-api skill?+

Run npx skills add anthropics/skills --skill claude-api and pick your agents, or use the tab for your agent above. In Claude Code the skill ends up in ~/.claude/skills/claude-api/SKILL.md; in Codex and Cursor in .agents/skills/claude-api/.

Does Claude API work in Codex, Cursor and Copilot, or only Claude?+

It's a standard SKILL.md, so any agent that reads the Agent Skills format can use it: Claude Code, the Claude apps, Codex, GitHub Copilot, Cursor, Gemini CLI, OpenCode, Windsurf and more.

Who maintains Claude API?+

Anthropic, the company or project behind it, in the anthropics/skills repo on GitHub, last pushed 2026-10-09. License: Complete terms in LICENSE.txt.

Read a skill's SKILL.md and scripts before you install it: skills aren't verified by any agent vendor. Claude skills marketplace · How to install skills · MCP servers