api-endpoint

A workflow for creating a REST API endpoint with its route, request checks, controller, and tests. A REST API endpoint is a web address that software uses to read or change a resource.

In plain words
What is it for?
Use it when adding a backend resource, including nested resources such as comments belonging to a post, with optional authentication.
Why use it?
It removes the repeated setup needed for CRUD operations—create, read, update, and delete—while including validation, error responses, and authentication tests.

Skill for Claude CodeCodex

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/zakelfassi/skills-driven-development/api-endpoint
Any agent
npx skills add zakelfassi/skills-driven-development --skill api-endpoint
Clone the repo
git clone --depth 1 https://github.com/zakelfassi/skills-driven-development

Made for: Claude Code, Codex.

Per session 40 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 590 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00040 $0.00590
Opus 5 $0.00020 $0.00295
Sonnet 5 $0.00008 $0.00118
Haiku 4.5 $0.00004 $0.00059

Measured 2d ago against content hash 89f8ba6ca487, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

api-endpoint 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 2d 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.

examples/webapp-starter/skills/api-endpoint/SKILL.md · 73 lines

What it actually says

API Endpoint Scaffold

Create a new REST API endpoint following project conventions.

Inputs

  • Entity name (singular, e.g., comment)
  • Fields (name:type pairs, e.g., body:string, author_id:number)
  • Auth required? (boolean, defaults to true)
  • Nested under? (optional parent entity, e.g., post)

Steps

  1. Create the route file

    src/routes/{entity}.routes.ts
    
    • Define CRUD routes: GET /, GET /:id, POST /, PUT /:id, DELETE /:id
    • If nested: GET /{parent}s/:parentId/{entity}s
  2. Create the controller

    src/controllers/{entity}.controller.ts
    
    • One method per route
    • All responses use { data, error, meta } shape
    • Handle not-found with 404, validation with 422
  3. Create the validation schema

    src/validators/{entity}.validator.ts
    
    • Use Zod schemas matching the field definitions
    • Separate schemas for create vs. update (update = partial)
  4. Create the test file

    tests/api/{entity}.test.ts
    
    • Test each CRUD operation
    • Test validation (bad input returns 422)
    • Test auth (if required: 401 without token)
    • Use test factories for fixtures
  5. Register the route

    src/routes/index.ts
    
    • Add import + app.use('/{entity}s', {entity}Routes)
    • If auth required: add auth middleware

Conventions

  • Route paths are plural (/comments, not /comment)
  • File names are singular (comment.routes.ts)
  • All endpoints return { data, error, meta }
  • meta includes pagination for list endpoints
  • Auth middleware is applied at the route level, not controller level

Edge Cases

  • File upload endpoints: Add multer middleware, accept multipart/form-data
  • Nested routes: Parent ID is validated in middleware (404 if parent doesn't exist)
  • Soft delete: DELETE sets deleted_at timestamp, doesn't remove the row
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. 2d ago First seen · 73 lines · 40 tokens per session scan A 89f8ba6ca487

Subscribe to this mod's changes

api-endpoint is a skill published in the GitHub repository zakelfassi/skills-driven-development (18 stars, last pushed 1mo ago), licensed MIT. It adds 40 tokens to every session and 590 once invoked, about $0.0002 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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