discover-api

A skill finder for designing and building APIs, which are interfaces that let software systems communicate. It covers REST, GraphQL, login and permissions, traffic limits, version changes, validation, and error responses.

In plain words
What is it for?
Use it when creating REST endpoints or GraphQL schemas, adding authentication or authorization, setting rate limits, versioning an API, or standardizing errors.
Why use it?
It helps avoid piecing together separate advice for endpoints, security, compatibility, and errors. Relevant API guidance is found automatically during backend work.

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/rand/cc-polymath/discover-api
Any agent
npx skills add rand/cc-polymath --skill discover-api
Clone the repo
git clone --depth 1 https://github.com/rand/cc-polymath

Made for: Claude Code, Codex.

Per session 47 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,398 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 $0.00047 $0.01398
Opus 5 $0.00023 $0.00699
Sonnet 5 $0.00009 $0.00280
Haiku 4.5 $0.00005 $0.00140

Measured 2d ago against content hash 3018948c82fc, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

discover-api 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.

skills/discover-api/SKILL.md · 208 lines

How it starts

The opening of the file, as written. The whole thing — 208 lines — stays where its author put it; the contents beside it link to each section on GitHub.

API Skills Discovery

Provides automatic access to comprehensive API design, authentication, and implementation skills.

When This Skill Activates

This skill auto-activates when you're working with:

  • REST API design and implementation
  • GraphQL schema design
  • API authentication (JWT, OAuth 2.0, API keys, sessions)
  • API authorization (RBAC, ABAC, permissions)
  • Rate limiting and throttling
  • API versioning strategies
  • Error handling and validation
  • HTTP methods, status codes, endpoints

Available Skills

Quick Reference

The API category contains 8 specialized skills:

  1. rest-api-design - RESTful resource modeling, HTTP semantics, URL conventions
  2. graphql-schema-design - GraphQL types, resolvers, N+1 problem prevention
  3. api-authentication - JWT, OAuth 2.0, API keys, session management
  4. api-authorization - RBAC, ABAC, policy engines, permission systems
  5. api-rate-limiting - Token bucket, sliding window, rate limiting algorithms
  6. api-versioning - API versioning, deprecation, backward compatibility
  7. api-error-handling - RFC 7807 errors, validation, standardized responses
  8. api-design-rules - 35 opinionated rules for API design

Load Full Category Details

For complete descriptions and workflows:

Read ../api/INDEX.md

This loads the full API category index with:

  • Detailed skill descriptions
  • Usage triggers for each skill
  • Common workflow combinations
  • Cross-references to related skills

Load Specific Skills

Load individual skills as needed:

Core API design

Read ../api/rest-api-design.md Read ../api/graphql-schema-design.md

Security and access control

Read ../api/api-authentication.md Read ../api/api-authorization.md

Production hardening

Read ../api/api-rate-limiting.md Read ../api/api-error-handling.md Read ../api/api-versioning.md

Rules and best practices

Read ../api/api-design-rules.md

Common Workflows

New REST API

Sequence: REST design → Authentication → Authorization

Read the full file on GitHub · 208 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. 2d ago First seen · 208 lines · 47 tokens per session scan A 3018948c82fc

Subscribe to this mod's changes

discover-api is a skill published in the GitHub repository rand/cc-polymath (136 stars, last pushed 6mo ago), licensed MIT. It adds 47 tokens to every session and 1,398 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.

Related

Other skills, from other repositories

claude-md-improver

Audit and improve CLAUDE.md files in repositories. Use when user asks to check, audit, update, improve, or fix CLAUDE.md files. Scans for all CLAUDE.md files, evaluates quality against templates, outputs quality report, then makes targeted updates. Also use when the user mentions "CLAUDE.md maintenance" or "project…

anthropics/claude-plugins-official · 82 tokens

agent-platform-rag-engine-management

Manage and query Agent Platform RAG Engine Corpora and retrieve grounded contexts using the Google GenAI SDK. Use when listing RAG corpora or files, inspecting a corpus, retrieving contexts, or generating content grounded in a RAG corpus. Do not use for standard database queries (use SQL/Spanner skills), Google…

google/skills · 85 tokens

agent-platform-model-registry

Agent Platform Model Registry Management. Use when you need to upload, list, describe, update, or delete machine learning models (and their versions) in the Agent Platform Model Registry. Don't use for model training, model deployment to endpoints, or managing non-Agent Platform models.

google/skills · 60 tokens

offensive-c2-frameworks

Command and Control framework deployment, configuration, and operational tradecraft for red team engagements. Covers Cobalt Strike (malleable C2 profiles, Beacon types HTTP/HTTPS/DNS/SMB, Beacon Object Files for in-memory execution, sleep and jitter tuning, named pipe pivoting), Sliver (implant generation across…

SnailSploit/Claude-Red · 250 tokens

twitter-reader

Read Twitter/X for financial research using opencli (read-only). Use this skill whenever the user wants to read their Twitter feed, search for financial tweets, view bookmarks, look up user profiles, or gather market sentiment from Twitter/X. Triggers include: "check my feed", "search Twitter for", "show my…

himself65/finance-skills · 161 tokens

quick-recap

Use when adding or following the red/yellow/green final status block convention for agent responses, especially by installing managed AGENTS.md or CLAUDE.md instructions.

BuilderIO/skills · 37 tokens