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API Contract

Category: Engineering  ·  Sub-category: backend  ·  Last updated:
Contract-First API design — write OpenAPI 3.1 or AsyncAPI 3.0 specs before implementation, generate or validate code against them, detect breaking changes in CI, and apply Consumer-Driven Contract Testing with Pact.
Security AStatic scan found no risk patternsHow grading works ›

From the source SKILL.md

The spec is the source of truth. Code is generated from it — or validated against it. Never the other way around.

What this skill does

API Contract is a community-contributed Claude Code skill in the backend sub-category. It ships as a SKILL.md file that Claude Code auto-discovers under ~/.claude/skills/api-contract/ and loads when your prompt matches the skill's trigger.

Who uses this skill

The API Contract Claude Code skill is built for software engineers, backend developers, full-stack teams, and technical leads building and maintaining production systems. It's part of ClaudSkills (also referred to as Claude Skills or Claude Code Skills) — the open community-curated registry of 146,000+ SKILL.md files for Anthropic's Claude Code agent and the wider Claude ecosystem (Claude API, Claude Agent SDK).

How to install

Free

Manual install (2 steps)

mkdir -p ~/.claude/skills/api-contract
curl -L https://claudskills.com/skills/api-contract/SKILL.md \
  -o ~/.claude/skills/api-contract/SKILL.md

Or just download SKILL.md directly and drop it into ~/.claude/skills/api-contract/. Claude Code auto-discovers it on next session.

Skills live at ~/.claude/skills/api-contract/SKILL.md on macOS/Linux, or %USERPROFILE%\.claude\skills\api-contract\SKILL.md on Windows. See the full install guide for step-by-step instructions.

Telegram

📱 Install from your phone or desktop Telegram

Open @claudskills_bot on Telegram, tap Open Desktop App, and the desktop app installs this skill for you. Or share the bot link with a colleague — they get the same one-tap install. Learn more →

Pro

One-click install via the desktop app

The ClaudSkills desktop app installs any skill directly into ~/.claude/skills/ with one click — no terminal required. Pro starts at $9/mo or $149 lifetime.

Pro

For the full experience including quality scoring and one-click install features for each skill — upgrade to Pro.

See pricing → Download desktop app

Frequently asked questions

How do I install the API Contract Claude Code skill?
Install via the ClaudSkills desktop app (one click) or copy SKILL.md from the source repository to ~/.claude/skills/api-contract/SKILL.md and restart Claude Code. Both flows are detailed at claudskills.com/install/.
What does the API Contract skill do?
Contract-First API design — write OpenAPI 3.1 or AsyncAPI 3.0 specs before implementation, generate or validate code against them, detect breaking changes in CI, and apply Consumer-Driven Contract Testing with Pact.
Is this skill free to install?
Yes. ClaudSkills is an open registry — every skill keeps its source repository's license, and manual install via copy is free. ClaudSkills Pro ($9/mo, $79/yr, or $149 one-time) adds one-click install via the desktop app and a multi-signal Quality Score.
When should I use the API Contract skill?
Use API Contract when your Claude Code task falls under the Engineering category — specifically in the backend area. Claude Code auto-discovers installed skills and invokes the right one based on the task description, so you can also ask Claude directly (e.g. "use API Contract" or describe the task and let Claude pick). Browse related skills at /category/engineering/.
What is a Claude Code skill and how does the API Contract skill fit in?
A Claude Code skill is a SKILL.md file that lives under ~/.claude/skills/<name>/ and tells the Claude Code CLI agent how to perform a specific task (instructions, prompts, allowed tools). Skills are auto-discovered at session start. API Contract is one of 67,000+ skills indexed in the open ClaudSkills catalog, classified under the Engineering category. Learn more at /learn/what-is-a-claude-skill/.

Attribution & license

Cite this skill

If you reference this skill in a blog post, paper, or documentation, you can cite it as:

APA
marvinrichter. (2026). API Contract [Claude Code skill]. ClaudSkills. https://claudskills.com/skills/api-contract/
BibTeX
@misc{api-contract-2026,
  author    = {marvinrichter},
  title     = {API Contract [Claude Code skill]},
  year      = {2026},
  publisher = {ClaudSkills},
  url       = {https://claudskills.com/skills/api-contract/}
}

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Security scan

Grade A · scanned 2026-07-06 — free static scan against the OWASP Agentic Skills Top 10.

No risk patterns were found in any of the ten OWASP-aligned categories. How grading works ›

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More Engineering skills

Browse all Engineering skills in the ClaudSkills registry, or explore these other picks from the same category:

Browse all Engineering skills → Top 100 skills
Part of ClaudSkills — the open registry for Claude Skills & Claude Code Skills.  ·  What's New  ·  Install guide  ·  About  ·  llms.txt

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