api-design

api-design is a skill for Claude Code from wshaddix/dotnet-skills. It costs 77 tokens per session (3,311 once invoked), scanned A, original, no licence file.

Guidance for designing public APIs: the methods, data, and rules that other programs use to work with a library or service. It focuses on changes that add support without breaking existing users.

In plain words
What is it for?
Use it when designing or changing APIs for NuGet packages, libraries, or distributed systems where compatibility matters.
Why use it?
It helps prevent updates from breaking applications that already depend on a package or service. It also gives consistent rules for names, parameters, return values, and versions.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the dotnet-skills plugin — 167 skills, 12 commands, 16 agents 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/wshaddix/dotnet-skills/csharp-api-design
Any agent
npx skills add wshaddix/dotnet-skills --skill csharp-api-design
Clone the repo
git clone --depth 1 https://github.com/wshaddix/dotnet-skills

Made for: Claude Code.

Or install dotnet-skills, the plugin that ships this one along with the rest of its 167 skills, 12 commands, 16 agents.

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 api-design

README.md
[![agentmods](https://agentmods.dev/badge/skills/wshaddix/dotnet-skills/csharp-api-design.svg)](https://agentmods.dev/skills/wshaddix/dotnet-skills/csharp-api-design)
Your own site
<a href="https://agentmods.dev/skills/wshaddix/dotnet-skills/csharp-api-design"><img src="https://agentmods.dev/badge/skills/wshaddix/dotnet-skills/csharp-api-design.svg" alt="Measured on agentmods" height="20"></a>
Per session 77 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,311 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 5.1 $0.00077 $0.03311
Opus 5 $0.00039 $0.01656
Sonnet 5 $0.00015 $0.00662
Haiku 4.5 $0.00008 $0.00331

Measured 6d ago against content hash 4fa651558670, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

api-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 6d 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/csharp-api-design/SKILL.md · 491 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

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. 6d ago First seen · 491 lines · 77 tokens per session scan A 4fa651558670

Subscribe to this mod's changes

api-design is a skill published in the GitHub repository wshaddix/dotnet-skills (79 stars, last pushed 6mo ago), with no licence file. It adds 77 tokens to every session and 3,311 once invoked, about $0.0004 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.

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