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memstack-development-api-designer

memstack-development-api-designer is a skill for Claude Code from cwinvestments/memstack. It costs 66 tokens per session (4,184 once invoked), scanned A, original, MIT.

A design guide for REST APIs, which let software communicate through organized web addresses called endpoints. It defines routes, input checks, response shapes, authentication checks, and error handling for Next.js server code.

In plain words
What is it for?
Use it to design API endpoints, route structures, request and response formats, webhook handlers, and Next.js App Router API routes.
Why use it?
It helps keep an API consistent and prevents common problems such as accepting invalid input, skipping authorization, or using unclear status codes.

Skill for Claude Code

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

Part of the memstack plugin — 87 skills, 2 commands, 6 hooks shipped together

not rated 429repo +2 changed 2mo ago A scan SkillSpector: warn 66 tokens original MIT

Good fit Use it to design API endpoints, route structures, request and response formats, webhook handlers, and Next.js App Router API routes.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/cwinvestments/memstack/api-designer
View source ↗ cwinvestments/memstack memstack.pro
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 cwinvestments/memstack --skill api-designer
Clone the repo
git clone --depth 1 https://github.com/cwinvestments/memstack

Made for: Claude Code.

Or install memstack, the plugin that ships this one along with the rest of its 87 skills, 2 commands, 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 memstack-development-api-designer

README.md
[![agentmods](https://agentmods.dev/badge/skills/cwinvestments/memstack/api-designer/github.svg)](https://agentmods.dev/skills/cwinvestments/memstack/api-designer)
Your own site
<a href="https://agentmods.dev/skills/cwinvestments/memstack/api-designer"><img src="https://agentmods.dev/badge/skills/cwinvestments/memstack/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 memstack-development-api-designer

Your own site · 80×15
<a href="https://agentmods.dev/skills/cwinvestments/memstack/api-designer"><img src="https://agentmods.dev/badge/skills/cwinvestments/memstack/api-designer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 66 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,184 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. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to high

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • high Tool Misuse · line 137
    Tool parameters are crafted to achieve unintended or unsafe behavior. Parameter abuse can bypass intended safety checks (e.g. shell=True, --force, dangerous glob patterns).
    Fix: Validate all tool parameters against an allowlist. Reject dangerous parameter values (shell=True, --force, -rf /) and use safe defaults.
How audits are shown
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 $0.00066 $0.04184
Opus 5.5 $0.00026 $0.01674
Sonnet 5.5 $0.00013 $0.00837
Haiku 4.5 $0.00007 $0.00418

Measured 2mo ago against content hash 2e15ecc0672a, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

memstack-development-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 2mo 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/development/api-designer/SKILL.md · 548 lines

How it starts

The opening of the file, as written. The whole thing — 548 lines — stays where its author put it; the contents beside it link to each section on GitHub.

🔌 API Designer: Designing routes, validation, and handler patterns...

Produces production-ready Next.js App Router API routes with auth guards, Zod validation, typed responses, and consistent error handling.

Activation

When this skill activates, output:

🔌 API Designer, Designing API routes and handlers...

Then execute the protocol below.

Context Status
User says "design API" or "create API route" or "add endpoint" ACTIVE
User says "REST API" or "route handler" ACTIVE
Building a new feature that needs API routes ACTIVE
Designing webhook endpoints ACTIVE
Discussing API concepts or REST theory DORMANT
Working on frontend components (not API layer) DORMANT

Anti-patterns

Trap Reality Check
"Auth is handled by middleware" Middleware can be bypassed. Every route handler must verify auth independently.
"I'll validate input later" Unvalidated input is the root of injection, type errors, and 500s. Zod first, logic second.
"Return 200 for everything" Status codes are the API contract. 401 vs 403 vs 404 vs 422 mean different things to clients.
"Error details help debugging" Stack traces and internal errors help attackers. Return safe messages, log details server-side.
"Rate limiting is a nice-to-have" Public endpoints without rate limits get abused within hours of deployment.
"TypeScript types are documentation enough" Types exist at build time. Zod schemas validate at runtime. You need both.

Protocol

Step 1: Design Route Structure

Map features to Next.js App Router file paths:

app/
  api/
    auth/
      login/route.ts          POST   - authenticate user
      logout/route.ts         POST   - clear session
      callback/route.ts       GET    - OAuth callback
    organizations/
      route.ts                GET    - list user's orgs
                              POST   - create org
      [orgId]/
        route.ts              GET    - get org details
                              PATCH  - update org
                              DELETE - delete org
        members/
          route.ts            GET    - list members
                              POST   - invite member
          [memberId]/
            route.ts          PATCH  - update role
                              DELETE - remove member
        projects/
          route.ts            GET    - list projects
                              POST   - create project
    webhooks/
      stripe/route.ts         POST   - Stripe webhook
      github/route.ts         POST   - GitHub webhook

Read the full file on GitHub · 548 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. 2mo ago Changed 2e15ecc0672a
  2. 2mo ago First seen · 548 lines · 66 tokens per session scan A 457b5f33c2da

Subscribe to this mod's changes

memstack-development-api-designer is a skill published in the GitHub repository cwinvestments/memstack (429 stars, last pushed 13d ago), licensed MIT. It adds 66 tokens to every session and 4,184 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 2026-08-30.

Backend and APIsClaude Codeai-codinganthropicclaudedeveloper-toolsvibe-coding
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