pattern-detector

pattern-detector is a skill for Claude Code from jhlee0409/claude-plugins. It costs 16 tokens per session (1,924 once invoked), scanned A, original, MIT.

A codebase analysis skill that studies existing examples to learn how a project handles API code. It detects the framework, language, HTTP client, data-fetching library, and recurring code patterns.

In plain words
What is it for?
Use it to inspect `package.json`, identify the technology stack, and search source folders for existing API implementations and patterns.
Why use it?
It reduces guesswork when adding API code to an unfamiliar project and helps new code follow the project's existing structure and conventions.

Skill for Claude Code

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

Part of the oas plugin — 6 skills, 6 commands shipped together

Good fit Use it to inspect package.json, identify the technology stack, and search source folders for existing API implementations and patterns.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/jhlee0409/claude-plugins/pattern-detector
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 jhlee0409/claude-plugins --skill pattern-detector
Clone the repo
git clone --depth 1 https://github.com/jhlee0409/claude-plugins

Made for: Claude Code.

Or install oas, the plugin that ships this one along with the rest of its 6 skills, 6 commands.

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 pattern-detector

README.md
[![agentmods](https://agentmods.dev/badge/skills/jhlee0409/claude-plugins/pattern-detector/github.svg)](https://agentmods.dev/skills/jhlee0409/claude-plugins/pattern-detector)
Your own site
<a href="https://agentmods.dev/skills/jhlee0409/claude-plugins/pattern-detector"><img src="https://agentmods.dev/badge/skills/jhlee0409/claude-plugins/pattern-detector/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 pattern-detector

Your own site · 80×15
<a href="https://agentmods.dev/skills/jhlee0409/claude-plugins/pattern-detector"><img src="https://agentmods.dev/badge/skills/jhlee0409/claude-plugins/pattern-detector.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 16 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,924 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. 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 $0.00016 $0.01924
Opus 5.5 $0.00006 $0.00770
Sonnet 5.5 $0.00003 $0.00385
Haiku 4.5 $0.00002 $0.00192

Measured 1mo ago against content hash 9edd90042612, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

pattern-detector scanned grade A with 1 finding 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

| axios | `import axios` or `import { } from 'axios'` | `axios.get()`, `axios.create()` |
plugins/oas/skills/pattern-detector/SKILL.md · 275 lines

How it starts

The opening of the file, as written. The whole thing — 275 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Pattern Detector

Analyze ANY codebase to learn existing API patterns. Works with any framework, structure, or convention.


EXECUTION INSTRUCTIONS

When this skill is invoked, Claude MUST perform these steps in order:

Step 1: Read package.json

  1. Use Read tool to read package.json in project root
  2. Extract dependency information:
    • dependencies
    • devDependencies
  3. If package.json not found → Report error and abort

Step 2: Detect Framework Stack

From package.json, identify:

Category Check for Result
Framework react, vue, @angular/core, svelte Set framework
HTTP Client axios, ky, got Set httpClient
Data Fetching @tanstack/react-query, swr, @reduxjs/toolkit Set dataFetching
Language typescript in devDeps Set language to typescript or javascript

Report findings:

📦 package.json analysis:
  Framework: <framework> + <language>
  HTTP Client: <httpClient or "fetch (native)">
  Data Fetching: <dataFetching or "none detected">

Step 3: Search for Existing API Code

Use Glob tool with these patterns in order:

1. src/**/api/**/*.{ts,js,tsx,jsx}
2. src/**/services/**/*.{ts,js}
3. src/**/hooks/**/*{api,query,fetch}*.{ts,js}
4. lib/api/**/*.{ts,js}
5. api/**/*.{ts,js}

If NO files found:

  • Report: 🔍 No existing API code found
  • Skip to Step 6 (Interactive Fallback)

If files found:

  • Report: 🔍 Found <count> potential API files
  • Continue to Step 4

Step 4: Analyze Sample Files

For each discovered file (max 5 files):

  1. Use Read tool to read file content
  2. Extract patterns:
    • Import patterns: What modules are imported, how (named, default, namespace)
    • Export patterns: Named exports, default exports, barrel exports
    • Function patterns: Arrow vs declaration, async, parameter style
    • HTTP call patterns: How HTTP requests are made
    • Type patterns: Interface vs type, naming conventions
    • Hook patterns: If React Query/SWR hooks present

Read the full file on GitHub · 275 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 · 275 lines · 16 tokens per session scan A 9edd90042612

Subscribe to this mod's changes

pattern-detector is a skill published in the GitHub repository jhlee0409/claude-plugins (4 stars, last pushed 9mo ago), licensed MIT. It adds 16 tokens to every session and 1,924 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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