Interface Contract Design includes worked examples; at least one code block. The SKILL.md runs to about 1,153 words, in the catalog's typical mid-range.
Interface Contract Design sits in the General category under the legal-compliance sub-topic in the ClaudSkills catalog. There are 10 related skills indexed alongside it; comparing a few before installing usually reveals which fits your workflow best.
These notes are auto-generated from features detected in the SKILL.md file and from this catalog's structure — they aren't part of the source repository.
Define what a boundary promises before anything implements or consumes it. Boundaries designed implementation-first leak internals into the contract and leave error semantics, idempotency, and versioning to be discovered by the first outage.
Interface Contract Design is a community-contributed Claude Code skill in the legal-compliance sub-category. It ships as a SKILL.md file that Claude Code auto-discovers under ~/.claude/skills/interface-contract-design/ and loads when your prompt matches the skill's trigger.
When to invoke it: Use when: designing or auditing the contract of a boundary before implementation: API, service interface, module boundary, message schema, or webhook — operations, inputs and outputs, error semantics, idempotency, ordering, versioning posture, and invariant ownership.
The Interface Contract Design Claude Code skill is built for Claude Code users and developers across all disciplines looking for general-purpose AI assistance. It's part of ClaudSkills (also referred to as Claude Skills or Claude Code Skills) — the open community-curated registry of 116,000+ SKILL.md files for Anthropic's Claude Code agent and the wider Claude ecosystem (Claude API, Claude Agent SDK).
mkdir -p ~/.claude/skills/interface-contract-design curl -L https://claudskills.com/skills/interface-contract-design/SKILL.md \ -o ~/.claude/skills/interface-contract-design/SKILL.md
Or just download SKILL.md directly and drop it into ~/.claude/skills/interface-contract-design/. Claude Code auto-discovers it on next session.
Skills live at ~/.claude/skills/interface-contract-design/SKILL.md on macOS/Linux, or %USERPROFILE%\.claude\skills\interface-contract-design\SKILL.md on Windows. See the full install guide for step-by-step instructions.
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 →
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.
For the full experience including quality scoring and one-click install features for each skill — upgrade to Pro.
SKILL.md from the source repository to ~/.claude/skills/interface-contract-design/SKILL.md and restart Claude Code. Both flows are detailed at claudskills.com/install/.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. Interface Contract Design is one of 67,000+ skills indexed in the open ClaudSkills catalog, classified under the General category. Learn more at /learn/what-is-a-claude-skill/.If you reference this skill in a blog post, paper, or documentation, you can cite it as:
@misc{interface-contract-design-2026,
author = {sjinks},
title = {Interface Contract Design [Claude Code skill]},
year = {2026},
publisher = {ClaudSkills},
url = {https://claudskills.com/skills/interface-contract-design/}
}Browse all General skills in the ClaudSkills registry, or explore these other picks from the same category:
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SKILL.md files, not affiliated with, endorsed by, or sponsored by Anthropic.