Plugin Validator by athola
Validates Claude Code plugin structure against official requirements
- Type
- Subagent
- Repository
- athola/claude-night-market
- GitHub stars
- 339
- License
- MIT
- Repo last updated
- Sep 24, 2026
- Source file
- plugins/abstract/agents/plugin-validator.md
- Model
- haiku
What Plugin Validator by athola is
Plugin Validator by athola is a subagent published in the athola/claude-night-market repository on GitHub, which has about 339 stars. The repository describes itself as: “23 Claude Code plugins: TDD enforcement hooks, git/PR workflows, spec-driven development, code review, project lifecycle, fix-from-error, maintenance automation, context optimization, research, and multi-LLM delegation. 186 skills, 128 commands, 54 agents.”
A subagent is a specialist assistant that Claude can hand part of a task to. It is a markdown file whose frontmatter sets a name, a description that tells Claude when to delegate, and optionally the tools and model it may use; the body becomes the subagent's own system prompt.
Because a subagent works in its own context, it keeps the main conversation focused: Claude can send a narrow job, such as a review or a specialised analysis, to Plugin Validator and get back a compact result.
How to install Plugin Validator by athola
Claude Code
- Download plugin-validator.md from the repository.
- Save it to ~/.claude/agents/ to use it in every project, or to .claude/agents/ inside one project to share it through version control.
- Claude Code watches these folders, so the subagent is usually available right away. Ask Claude to use it by name, or @-mention it to make sure it runs.
Claude Cowork
- Cowork loads subagents through plugins. If the repository is packaged as a plugin marketplace, add it under Customize → Plugins → Add marketplace and install the plugin that contains this subagent.
- Otherwise, bundle the file into your own plugin's agents/ folder and upload it from Customize → Plugins.
New to extending Cowork? Our plugins guide and Customize guide explain how skills, plugins, and connectors fit together.
Inside the source file
An excerpt from plugins/abstract/agents/plugin-validator.md, shared under the repository's MIT license. Read the full file on GitHub.
Validates Claude Code plugin structure against official requirements and best practices.
Capabilities
- Validates .claude-plugin/plugin.json exists and is valid JSON
- Checks required fields (name) and recommended fields (version, description, keywords)
- Validates kebab-case naming convention
- Verifies referenced files/paths exist (skills, commands, agents, hooks)
- Validates hooks.json references and JSON syntax
- Checks path format (relative with ./)
- Validates skill frontmatter completeness
- Detects deprecated skills/shared/ directory pattern (modules should be skill-specific)
Claude Code 2.1.0+ Validation
The validator recognizes and validates new 2.1.0 frontmatter fields:
Wildcard Patterns Validated:
- Bash(npm *) - All npm commands
- Bash(* install) - Any install command
- Bash(git * main) - Git with main branch
Wildcard Normalization (2.1.20+):
- ⚠️ Bash(*) is now treated as equivalent to plain Bash: warn if encountered
- Scoped wildcards like Bash(npm *) remain distinct and valid
- Validation should flag Bash(*) as redundant: suggest using Bash instead
Agent Memory Field (2.1.33+)
Agents can declare persistent memory scope in frontmatter:
Validation: Warn if memory value is not one of: user, project, local.
Sub-Agent Restrictions (2.1.33+)
Agent tools frontmatter supports Task(agent_type) syntax to restrict sub-agent spawning:
tools:
- Read
- Task(code-reviewer)Validation: Verify Task(agent_type) references use valid kebab-case names. Optionally verify referenced agent types exist in the plugin or ecosystem.
Hook Structure Validated:
hooks:
PreToolUse:
- matcher: "Bash|Edit"
command: "./script.sh"
once: true # Optional, runs only once per session
PostToolUse:
- matcher: "Write"
command: "./format.sh"
Stop:
- command: "./cleanup.sh"Validation Process
Step 0: Complexity Check (MANDATORY)
Before any work, assess if this task justifies subagent overhead:
Return early if:
- User just wants pass/fail → "SIMPLE: python3 .../validate_plugin.py "
- Single plugin, no interpretation needed → "SIMPLE: Parent runs script directly"
- Quick syntax check → "SIMPLE: Parent runs jq . plugin.json"
Continue if:
- Multiple plugins to validate and compare
- Detailed error interpretation needed
- Follow-up fixes and re-validation cycle
- Integration with other workflows
Steps 1-6 (Only if Complexity Check passes)
- Structure Check: Verify .claude-plugin/plugin.json location
- JSON Validation: Parse and validate JSON syntax
- Required Fields: Check for mandatory fields
- Path Validation: Verify all referenced paths exist
- Naming Convention: Validate kebab-case for plugin name
- Best Practices: Check for recommended metadata
Usage
When dispatched, provide the plugin path to validate:
Validate the plugin at /path/to/pluginOutput
Returns validation report with:
- ERRORS: Critical issues that will prevent plugin from working
- WARNINGS: Issues that may cause problems
- RECOMMENDATIONS: Best practice suggestions
- INFO: Confirmations of what passed
Implementation
python3 /home/alext/claude-night-market/plugins/abstract/scripts/validate_plugin.py <plugin-path> Before you install
- Read the whole file first. Skills, commands, and subagents are instructions Claude will follow, so make sure they match what you want.
- Check which tools, scripts, or MCP servers it uses. Local servers and scripts run with your permissions.
- Try it in a test project or a copy of your files before pointing it at real work.
- Pin the version you tested, and review changes before updating.
- Watch for instructions that fetch web content or run shell commands; those are where prompt injection risks start. See our prompt injection guide.
FAQ
What is Plugin Validator by athola?
Plugin Validator by athola is a subagent for Claude Code and Claude Cowork from the athola/claude-night-market repository on GitHub. Validates Claude Code plugin structure against official requirements
How do I install Plugin Validator by athola in Claude Code?
Download plugin-validator.md from the repository. Save it to ~/.claude/agents/ to use it in every project, or to .claude/agents/ inside one project to share it through version control. Claude Code watches these folders, so the subagent is usually available right away. Ask Claude to use it by name, or @-mention it to make sure it runs.
Can I use Plugin Validator by athola in Claude Cowork?
Cowork loads subagents through plugins. If the repository is packaged as a plugin marketplace, add it under Customize → Plugins → Add marketplace and install the plugin that contains this subagent. Otherwise, bundle the file into your own plugin's agents/ folder and upload it from Customize → Plugins.
Is Plugin Validator by athola safe to install?
It is a third-party community resource, not reviewed by Anthropic or this site. Read the source file first, check which tools and connectors it uses, and install only from sources you trust.
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