Overview
claude-api is an open-source backend skill for Claude Code and compatible agents, published by anthropics. Its author describes it as: “Reference for the Claude API / Anthropic SDK — model ids, pricing, params, streaming, tool use, MCP, agents, caching, token counting, model migration. TRIGGER — read BEFORE opening the target file; don't skip because…”. The project has 177k stars on GitHub and ships custom license terms, so review them before reuse. Add it to your setup with `/plugin marketplace add anthropics/skills`.
What claude-api does
This skill helps you build LLM-powered applications with Claude. Choose the right surface based on your needs, detect the project language, then read the relevant language-specific documentation.
Best for
What’s inside
The SKILL.md for claude-api is organised into these 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: 2026-06-24)
Installation
Add claude-api to your agent with:
/plugin marketplace add anthropics/skillsReview a skill’s source before installing it — skills can instruct your agent to run commands. This command comes from the skill’s public repository, which is the source of truth for setup steps. New to skills? Read how to install Claude Code skills.
Supported agents
- Claude Code — ships a claude code plugin marketplace
License
anthropics has not declared a standard open-source license for this repository (Complete terms in LICENSE.txt). Confirm the terms with the author before reusing it.
Strengths
- Ships in anthropics/skills, an established project with 177,416 GitHub stars
- Works with Claude Code
- Actively maintained — repository updated in the last 30 days
- Its repository gained 12,054 GitHub stars over the last 52 days
Things to check
- No license declared — confirm terms with the author before reuse
Author
Topics
Frequently asked questions
- What does claude-api do?
- Reference for the Claude API / Anthropic SDK — model ids, pricing, params, streaming, tool use, MCP, agents, caching, token counting, model migration. TRIGGER — read BEFORE opening the target file; don't skip because it "looks like a one-liner" — whenever: the prompt names Claude/Anthropic in any form (Claude, Anthropic, Fable, Opus, Sonnet, Haiku, `anthropic`, `@anthropic-ai`, `claude-*`, `us.anthropic.*`, `[1m]`); the user asks about an LLM (pricing/model choice/limits/caching) — never answer from memory; OR the task is LLM-shaped with provider unstated (agent/MCP/tool-definition/multi-agent/RAG/LLM-judge/computer-use; generate/summarize/extract/classify/rewrite/converse over NL; debugging refusals/cutoffs/streaming/tool-calls/tokens). SKIP only when another provider is being worked on (overrides all triggers): OpenAI/GPT/Gemini/Llama/Mistral/Cohere/Ollama named in the query; OR `grep -rE 'openai|langchain_openai|google.generativeai|genai|mistralai|cohere|ollama'` over the project hits (run this grep FIRST if no provider named — don't Read the file).
- How do I install claude-api?
- Run /plugin marketplace add anthropics/skills in your agent, then reload your skills. Review the source at https://github.com/anthropics/skills before installing.
- Is claude-api free to use?
- claude-api is publicly available on GitHub, but anthropics has not declared a standard open-source license (Complete terms in LICENSE.txt). Confirm the terms with the author before reusing it.
- Which agents does claude-api work with?
- claude-api lists Claude Code — named in its SKILL.md, its plugin marketplace or its repository topics. Skills use the portable SKILL.md format, so other agents that read that format may load it too.
- Where does claude-api come from?
- claude-api ships inside anthropics/skills, a repository that contains 21 catalogued skills in total. The repository's 177,416 GitHub stars apply to that whole collection, not to this skill on its own.
