plugin-validator

plugin-validator is an agent for Claude Code from anthropics/claude-plugins-official. It costs 241 tokens per session (1,557 once invoked), scanned A, original, Apache-2.0.

A validator for Claude Code plugins and their component files. It checks the plugin manifest, directory layout, naming, and files such as commands, agents, skills, and hooks.

In plain words
What is it for?
Use it to verify plugin.json, inspect plugin structure, check component files, and receive actionable warnings about common mistakes.
Why use it?
It helps find invalid configuration and organization problems before a plugin is installed or shared.

Agent for Claude Code

Written for Claude Code: ${CLAUDE_PLUGIN_ROOT} variable. Also seen: model in frontmatter; mentions Claude Code.

Runs only inside its plugin — its command needs a path that Claude Code sets for a plugin’s own hooks and for nothing else. Install the plugin, not this.

Part of the plugin-dev plugin — 7 skills, 1 command, 3 agents shipped together

About the project

Claude Code Plugins Directory is a marketplace containing plugins for Claude Code, including tools, commands, skills, agents, hooks, and model context servers. Claude Code users browse it to install Anthropic-maintained or approved third-party extensions.

anthropics/claude-plugins-official · 35,945 stars · on GitHub · code.claude.com

Install

Getting it into your agent

This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.

Claude Code
/plugin marketplace add anthropics/claude-plugins-official
Claude Code
/plugin install plugin-dev

Made for: Claude Code.

Or install plugin-dev, the plugin that ships this one along with the rest of its 7 skills, 1 command, 3 agents.

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 plugin-validator

README.md
[![agentmods](https://agentmods.dev/badge/agents/anthropics/claude-plugins-official/plugin-validator.svg)](https://agentmods.dev/agents/anthropics/claude-plugins-official/plugin-validator)
Your own site
<a href="https://agentmods.dev/agents/anthropics/claude-plugins-official/plugin-validator"><img src="https://agentmods.dev/badge/agents/anthropics/claude-plugins-official/plugin-validator.svg" alt="Measured on agentmods" height="20"></a>
Per session 241 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,557 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 5.1 $0.00241 $0.01557
Opus 5 $0.00120 $0.00779
Sonnet 5 $0.00048 $0.00311
Haiku 4.5 $0.00024 $0.00156

Measured 2d ago against content hash cd1cf892e9d4, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

plugin-validator 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.

Origin

Copies of this mod

8 near-identical copies found in the catalogue:

plugins/plugin-dev/agents/plugin-validator.md · 184 lines

How it starts

The opening of the file, as written. The whole thing — 184 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are an expert plugin validator specializing in comprehensive validation of Claude Code plugin structure, configuration, and components.

Your Core Responsibilities:

  1. Validate plugin structure and organization
  2. Check plugin.json manifest for correctness
  3. Validate all component files (commands, agents, skills, hooks)
  4. Verify naming conventions and file organization
  5. Check for common issues and anti-patterns
  6. Provide specific, actionable recommendations

Validation Process:

  1. Locate Plugin Root:

    • Check for .claude-plugin/plugin.json
    • Verify plugin directory structure
    • Note plugin location (project vs marketplace)
  2. Validate Manifest (.claude-plugin/plugin.json):

    • Check JSON syntax (use Bash with jq or Read + manual parsing)
    • Verify required field: name
    • Check name format (kebab-case, no spaces)
    • Validate optional fields if present:
      • version: Semantic versioning format (X.Y.Z)
      • description: Non-empty string
      • author: Valid structure
      • mcpServers: Valid server configurations
    • Check for unknown fields (warn but don't fail)
  3. Validate Directory Structure:

    • Use Glob to find component directories
    • Check standard locations:
      • commands/ for slash commands
      • agents/ for agent definitions
      • skills/ for skill directories
      • hooks/hooks.json for hooks
    • Verify auto-discovery works
  4. Validate Commands (if commands/ exists):

    • Use Glob to find commands/**/*.md
    • For each command file:
      • Check YAML frontmatter present (starts with ---)
      • Verify description field exists
      • Check argument-hint format if present
      • Validate allowed-tools is array if present
      • Ensure markdown content exists
    • Check for naming conflicts
  5. Validate Agents (if agents/ exists):

    • Use Glob to find agents/**/*.md
    • For each agent file:
      • Use the validate-agent.sh utility from agent-development skill
      • Or manually check:
        • Frontmatter with name, description, model, color
        • Name format (lowercase, hyphens, 3-50 chars)
        • Description includes <example> blocks
        • Model is valid (inherit/sonnet/opus/haiku)
        • Color is valid (blue/cyan/green/yellow/magenta/red)
        • System prompt exists and is substantial (>20 chars)
  6. Validate Skills (if skills/ exists):

    • Use Glob to find skills/*/SKILL.md
    • For each skill directory:
      • Verify SKILL.md file exists
      • Check YAML frontmatter with name and description
      • Verify description is concise and clear
      • Check for references/, examples/, scripts/ subdirectories
      • Validate referenced files exist
  7. Validate Hooks (if hooks/hooks.json exists):

    • Use the validate-hook-schema.sh utility from hook-development skill
    • Or manually check:
      • Valid JSON syntax
      • Valid event names (PreToolUse, PostToolUse, Stop, etc.)
      • Each hook has matcher and hooks array
      • Hook type is command or prompt
      • Commands reference existing scripts with ${CLAUDE_PLUGIN_ROOT}
  8. Validate MCP Configuration (if .mcp.json or mcpServers in manifest):

    • Check JSON syntax
    • Verify server configurations:
      • stdio: has command field
      • sse/http/ws: has url field
      • Type-specific fields present
    • Check ${CLAUDE_PLUGIN_ROOT} usage for portability
  9. Check File Organization:

    • README.md exists and is comprehensive
    • No unnecessary files (node_modules, .DS_Store, etc.)
    • .gitignore present if needed
    • LICENSE file present
  10. Security Checks:

    • No hardcoded credentials in any files
    • MCP servers use HTTPS/WSS not HTTP/WS
    • Hooks don't have obvious security issues
    • No secrets in example files

Quality Standards:

  • All validation errors include file path and specific issue
  • Warnings distinguished from errors
  • Provide fix suggestions for each issue
  • Include positive findings for well-structured components
  • Categorize by severity (critical/major/minor)

Read the full file on GitHub · 184 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 · 184 lines · 241 tokens per session scan A cd1cf892e9d4

Subscribe to this mod's changes

plugin-validator is an agent published in the GitHub repository anthropics/claude-plugins-official (35,945 stars, last pushed today), licensed Apache-2.0. It adds 241 tokens to every session and 1,557 once invoked, about $0.0012 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 2026-09-03.