Design An API

by testdouble

Design An API is an AI Engineering skill for Claude Code, published by testdouble in han.

253 stars22 forkson testdouble/hanAdded 2026/09/02+9% in starsRepository updated 2026/09/01

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Install in seconds

Install Design An API

Copy Design An API into your Claude Code skills folder. Run the command in your terminal, or review the source on GitHub before installing.

terminal

npx degit https://github.com/testdouble/han/tree/main/han-coding/skills/design-an-api ~/.claude/skills/design-an-api

Requires Node.js. Downloads this skill only — not the rest of the repository — into your Claude Code skills folder.

Without Node.js

git clone https://github.com/testdouble/han.git

Clones the whole repository, then copy the skill’s own directory into your skills folder yourself.

In this catalog

Source file: han-coding/skills/design-an-api/SKILL.md in testdouble/han
Installs to: ~/.claude/skills/design-an-api
Collection: One of 25 skills cataloged from this repository
Category: AI Engineering — 2631 skills

What Design An API does

Design An API defines the contract for an API or interface change inside one codebase. Use it when you need to shape props, signatures, parameters, payloads, or module boundaries without writing code.

Design An API is cataloged under AI Engineering on DirSkills. Design An API comes from a repository tagged claude, claude-code, claude-code-plugin, claude-skills and code-review.

Documentation

README

Excerpt

Project Context

git installed: !which git 2>/dev/null || echo "not installed"
current branch: !git branch --show-current 2>/dev/null || echo "no git branch"
default branch: !git symbolic-ref --short refs/remotes/origin/HEAD 2>/dev/null || echo unknown
CLAUDE.md: !find . -maxdepth 1 -name "CLAUDE.md" -type f
project-discovery.md: !find . -maxdepth 3 -name "project-discovery.md" -type f
personal config directory: !bash "${CLAUDE_PLUGIN_ROOT}/scripts/han-config-dir.sh" 2>/dev/null || echo "$HOME/.claude"
project .han/config.md: !cat .han/config.md 2>/dev/null || echo ""

This is the opening of the README. Read the full README on GitHub.

Frequently asked about Design An API

What else does testdouble publish alongside Design An API?
Design An API is one of 25 skills that DirSkills catalogs from testdouble/han, the repository it ships in. Its siblings there include Architectural Analysis, Automated Test Planning and Code Overview. Each one is a separate skill with its own page in this directory, installs the same way Design An API does, and is maintained by testdouble in that same repository. The rest of the collection is listed on the testdouble/han page.
How does Design An API compare to other AI Engineering skills?
Design An API ranks #2298 by stars among the 2631 AI Engineering skills in this catalog. The most-starred ones next to it are Architecture Decision Records, AI-First Engineering and Agentic OS. DirSkills ranks by the star count of the repository each skill ships in, so that order reflects how popular those repositories are rather than any review of Design An API against them. Open each page to compare what they document and how they install.