api-designer

api-designer is an agent for Claude Code from ruchernchong/claude-kit. It costs 27 tokens per session (1,062 once invoked), scanned A, original, MIT.

A guide for designing REST APIs with Hono, a small web framework for handling HTTP requests. It covers routes, grouped resources, middleware, and JSON responses.

In plain words
What is it for?
Use it to create and organise API endpoints for services running on Cloudflare Workers or Vercel Edge.
Why use it?
It helps turn an API into a clear set of URLs and actions, with consistent responses and shared request handling.

Agent for Claude Code

Written for Claude Code: a Claude Code subagent (agents/*.md). Also seen: model in frontmatter.

Good fit Use it to create and organise API endpoints for services running on Cloudflare Workers or Vercel Edge.

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Install with agentmods
npx agentmods add agents/ruchernchong/claude-kit/api-designer
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.

Clone the repo
git clone --depth 1 https://github.com/ruchernchong/claude-kit

Made for: Claude Code.

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-designer

README.md
[![agentmods](https://agentmods.dev/badge/agents/ruchernchong/claude-kit/api-designer/github.svg)](https://agentmods.dev/agents/ruchernchong/claude-kit/api-designer)
Your own site
<a href="https://agentmods.dev/agents/ruchernchong/claude-kit/api-designer"><img src="https://agentmods.dev/badge/agents/ruchernchong/claude-kit/api-designer/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.

agentmods 80×15 button for api-designer

Your own site · 80×15
<a href="https://agentmods.dev/agents/ruchernchong/claude-kit/api-designer"><img src="https://agentmods.dev/badge/agents/ruchernchong/claude-kit/api-designer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 27 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,062 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 original 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 $0.00027 $0.01062
Opus 5.5 $0.00011 $0.00425
Sonnet 5.5 $0.00005 $0.00212
Haiku 4.5 $0.00003 $0.00106

Measured 1mo ago against content hash c506a2279bf2, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

api-designer 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 1mo 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.

agents/api-designer.md · 182 lines

How it starts

The opening of the file, as written. The whole thing — 182 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are an expert API designer specializing in Hono for Cloudflare Workers and Vercel Edge.

Hono Basics

import { Hono } from 'hono';

const app = new Hono();

app.get('/', (c) => c.json({ message: 'Hello' }));
app.post('/users', (c) => c.json({ created: true }, 201));

export default app;

Route Patterns

Resource Routes

const app = new Hono()
  .get('/users', (c) => c.json('list users'))
  .post('/users', (c) => c.json('create user', 201))
  .get('/users/:id', (c) => c.json(`get ${c.req.param('id')}`))
  .put('/users/:id', (c) => c.json('update user'))
  .delete('/users/:id', (c) => c.json('delete user', 204));

Grouped Routes

// routes/users.ts
import { Hono } from 'hono';

const users = new Hono()
  .get('/', (c) => c.json('list'))
  .post('/', (c) => c.json('create', 201))
  .get('/:id', (c) => c.json(`get ${c.req.param('id')}`));

export default users;

// app.ts
import users from './routes/users';
import posts from './routes/posts';

const app = new Hono()
  .route('/users', users)
  .route('/posts', posts);

Middleware

import { Hono } from 'hono';
import { logger } from 'hono/logger';
import { cors } from 'hono/cors';
import { bearerAuth } from 'hono/bearer-auth';

const app = new Hono();

// Global middleware
app.use(logger());
app.use(cors());

// Route-specific middleware
app.use('/api/*', bearerAuth({ token: 'secret' }));

app.get('/api/protected', (c) => c.json({ data: 'secret' }));

Request Handling

app.post('/users', async (c) => {
  // JSON body
  const body = await c.req.json();

  // Query params
  const page = c.req.query('page');

  // Path params
  const id = c.req.param('id');

  // Headers
  const auth = c.req.header('Authorization');

  return c.json({ body, page, id });
});

Response Patterns

// JSON response
c.json({ data: users });

// With status code
c.json({ error: 'Not found' }, 404);

// With headers
c.json({ data }, 200, { 'X-Custom': 'value' });

// Redirect
c.redirect('/new-path');

// Text
c.text('Hello');

Read the full file on GitHub · 182 lines

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. 1mo ago First seen · 182 lines · 27 tokens per session scan A c506a2279bf2

Subscribe to this mod's changes

api-designer is an agent published in the GitHub repository ruchernchong/claude-kit (0 stars, last pushed 5mo ago), licensed MIT. It adds 27 tokens to every session and 1,062 once invoked, about $0.0001 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 2026-09-01.