Claude Code Plugin Builder

A builder for Claude Code plugins, which are add-ons that extend Claude Code with commands, agents, skills, hooks, and connections to MCP servers. It creates the required manifest and folder structure.

In plain words
What is it for?
Use it to create a new Claude Code plugin and organize its commands, agents, skills, hooks, and MCP server components.
Why use it?
It helps avoid loading errors caused by putting plugin files in the wrong folders or leaving out required manifest details. It is specifically for Claude Code plugins, not Codex plugins.

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/pleaseai/claude-code-plugins/claude-code-plugin-builder
Any agent
npx skills add pleaseai/claude-code-plugins --skill claude-code-plugin-builder
Clone the repo
git clone --depth 1 https://github.com/pleaseai/claude-code-plugins

Made for: Claude Code, Codex.

Per session 139 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,494 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 $0.00139 $0.02494
Opus 5 $0.00069 $0.01247
Sonnet 5 $0.00028 $0.00499
Haiku 4.5 $0.00014 $0.00249

Measured 2d ago against content hash 3aa73f55a485, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

Claude Code Plugin Builder 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.

.claude/skills/claude-code-plugin-builder/SKILL.md · 403 lines

How it starts

The opening of the file, as written. The whole thing — 403 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Claude Code Plugin Builder

Expert skill for developing professional Claude Code plugins.

Critical Directory Rules

Components MUST be at plugin root, NOT inside .claude-plugin/:

✅ CORRECT:
plugin/
├── .claude-plugin/plugin.json  # Only manifest here
├── commands/                    # At root
├── agents/                      # At root
├── skills/                      # At root
└── hooks/                       # At root

❌ WRONG:
plugin/.claude-plugin/
├── plugin.json
├── commands/      # Won't load
└── agents/        # Won't load

Plugin Creation Workflow

1. Initialize Structure

mkdir -p my-plugin/.claude-plugin
mkdir -p my-plugin/{commands,agents,skills,hooks}

2. Create Manifest

Minimal (my-plugin/.claude-plugin/plugin.json):

{
  "name": "my-plugin",
  "version": "1.0.0",
  "description": "What this plugin does"
}

Complete:

{
  "name": "plugin-name",
  "version": "1.0.0",
  "description": "Brief description",
  "author": {
    "name": "Your Name",
    "email": "[email protected]",
    "url": "https://github.com/user"
  },
  "repository": "https://github.com/org/repo",
  "license": "MIT",
  "keywords": ["tag1", "tag2"],
  "hooks": "./hooks/hooks.json",
  "mcpServers": {
    "server-name": {
      "command": "npx",
      "args": ["-y", "@org/package"],
      "env": {
        "API_KEY": "${API_KEY:-}"
      }
    }
  }
}

3. Add Components

Commands (user-invoked):

<!-- commands/deploy.md -->
---
description: Deploy to production
validation:
  requiresFiles: ["package.json"]
---

# Deploy Command

1. Verify deployment readiness
2. Execute: npm run deploy
3. Monitor deployment status
4. Report results

Agents (autonomous specialists):

<!-- agents/security-expert.md -->
---
description: Security vulnerability analysis expert
capabilities: ["vulnerability-scan", "audit", "remediation"]
---

# Security Expert

Specializes in OWASP vulnerabilities, CVE analysis, dependency scanning.

Invoke for: security audits, vulnerability assessments, compliance reviews.

Read the full file on GitHub · 403 lines

Files

What ships with it

4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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 · 403 lines · 139 tokens per session scan A 3aa73f55a485

Subscribe to this mod's changes

Claude Code Plugin Builder is a skill published in the GitHub repository pleaseai/claude-code-plugins (13 stars, last pushed 7d ago), licensed MIT. It adds 139 tokens to every session and 2,494 once invoked, about $0.0007 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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