contract-design

contract-design is a skill for Claude Code, Codex from geekatron/jerry. It costs 112 tokens per session (6,024 once invoked), scanned A, original, no licence file.

A skill that generates API contracts from use-case realization artifacts. An API contract is a precise description of the operations, requests, responses, and rules that an API exposes; this skill uses interaction sequences to create OpenAPI 3.1 specifications and preserve links to their source steps.

In plain words
What is it for?
Use it to transform use-case interaction sequences into OpenAPI 3.1 contracts, map operations to source steps, derive HTTP methods, extract schemas, and validate the result.
Why use it?
It helps turn requirements-focused interaction details into a structured API description. Validation and traceability make it easier to find gaps between the use cases and the contract.

Skill for Claude CodeCodex

Part of the jerry plugin — 32 skills, 2 commands, 89 agents, 6 hooks shipped together

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.

agentmods
npx agentmods add skills/geekatron/jerry/contract-design
Any agent
npx skills add geekatron/jerry --skill contract-design
Clone the repo
git clone --depth 1 https://github.com/geekatron/jerry

Made for: Claude Code, Codex.

Or install jerry, the plugin that ships this one along with the rest of its 32 skills, 2 commands, 89 agents, 6 hooks.

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.

agentmods badge for contract-design

README.md
[![agentmods](https://agentmods.dev/badge/skills/geekatron/jerry/contract-design.svg)](https://agentmods.dev/skills/geekatron/jerry/contract-design)
Your own site
<a href="https://agentmods.dev/skills/geekatron/jerry/contract-design"><img src="https://agentmods.dev/badge/skills/geekatron/jerry/contract-design.svg" alt="Measured on agentmods" height="20"></a>
Per session 112 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 6,024 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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.

ModelPer sessionOnce invoked
Fable 5 $0.00112 $0.06024
Opus 5 $0.00056 $0.03012
Sonnet 5 $0.00022 $0.01205
Haiku 4.5 $0.00011 $0.00602

Measured 5d ago against content hash 26c26837dee2, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

contract-design 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 5d ago.

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.

skills/contract-design/SKILL.md · 434 lines

The source is not reproduced here

A licence we could not identify

The repository carries a LICENSE file, but it is custom or dual enough that GitHub cannot name it and neither can this catalogue. Unknown terms are not permission, so the body is not copied here. Read the licence at the source and decide for yourself.

Read it on GitHub

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.

  1. 5d ago First seen · 434 lines · 112 tokens per session scan A 26c26837dee2

Subscribe to this mod's changes

contract-design is a skill published in the GitHub repository geekatron/jerry (32 stars, last pushed 2d ago), with no licence file. It adds 112 tokens to every session and 6,024 once invoked, about $0.0006 per session on Opus 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 2026-08-30.