What is api-contract?

A skill for defining the agreement between a frontend and backend API before coding. An API is the interface software uses to exchange requests and responses, including field names and data formats.

Use it to design request and response fields, set naming conventions, align teams on interfaces, and create an api.md file for each page.

It reduces misunderstandings between frontend and backend developers about what each endpoint accepts and returns.

api-contract — Skill for Claude Code and Codex by ChenyCHENYU

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent

npx skills add ChenyCHENYU/wl-skills-kit --skill api-contract

Clone the repo

git clone --depth 1 https://github.com/ChenyCHENYU/wl-skills-kit

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/chenychenyu/wl-skills-kit/api-contract/github.svg)](https://agentmods.dev/skills/chenychenyu/wl-skills-kit/api-contract)

Your own site

<a href="https://agentmods.dev/skills/chenychenyu/wl-skills-kit/api-contract"><img src="https://agentmods.dev/badge/skills/chenychenyu/wl-skills-kit/api-contract/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/chenychenyu/wl-skills-kit/api-contract"><img src="https://agentmods.dev/badge/skills/chenychenyu/wl-skills-kit/api-contract.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 63 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 4,515 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin unknown No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00063	$0.04515
Opus 5.5	$0.00025	$0.01806
Sonnet 5.5	$0.00013	$0.00903
Haiku 4.5	$0.00006	$0.00451

Measured today against content hash bfb48d9ee14e, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

api-contract scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured today.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

files/.wl-skills/skills/core/api-contract/SKILL.md · 415 lines

The source is not reproduced here

No licence file

Read it on GitHub

Files

What ships with it

2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

today Changed · -13 tokens per session bfb48d9ee14e
1mo ago Changed · +2 lines 1c6bc23c74ba
2mo ago First seen · 413 lines · 76 tokens per session scan A 5d24903a979f

Subscribe to this mod's changes

api-contract is a skill published in the GitHub repository ChenyCHENYU/wl-skills-kit (5 stars, last pushed today), with no licence file. It adds 63 tokens to every session and 4,515 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

Backend and APIs Frontend

api-contract next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
api-contractChenyCHENYU/wl-skills-kit	Skill	5	today	none	A	63	Claude Code, Codex
mem0-oss-to-platformmem0ai/mem0	Skill	69k	today	Apache-2.0	A	217	Claude Code, Codex
azure-mgmt-botservice-dotnetmicrosoft/skills	Skill	3.2k	yesterday	MIT	A	78	Claude Code
fastapi-router-pymicrosoft/skills	Skill	3.2k	yesterday	MIT	A	46	Claude Code
dev-runtimelangwatch/langwatch	Skill	5.0k	yesterday	Apache-2.0	A	172	Claude Code
api-designericrisco/rsc-harness	Skill	503	2d ago	MIT	A	105	Claude Code, Codex
migrate-segw-to-raparc-mcp/arc-1	Skill	252	yesterday	MIT	A	106	Claude Code