Claude Code Conventions

Claude Code Plugin Conventions Reference

Purpose: This skill is the single source of truth for Claude Code artifact conventions. Audit commands inject this content into Codex's developer-instructions so Codex can accurately validate Claude Code artifacts despite having no native knowledge of the platform.

Freshness: Last updated 2026-03-25 from context7 (/websites/code_claude_en_plugins-reference, /websites/code_claude_en_plugins). Run /cc-suite:refresh-knowledge to refresh.

When to Use

Load this skill when:

• Auditing Claude Code plugin artifacts (commands, agents, skills, hooks, plugin.json)
• Validating frontmatter fields against the official schema
• Checking hook event names, types, and output formats
• Authoring new plugin artifacts and need the canonical field reference
• Running /cc-suite:audit-plugin, /cc-suite:audit-command, /cc-suite:audit-agent, or /cc-suite:audit-skill

plugin.json Schema

Only name is strictly required. Version and description are strongly recommended but optional.

Required:

• name (string): plugin identifier, kebab-case. Used for namespacing (e.g., plugin-dev:agent-creator)

Recommended:

• version (string): semver X.Y.Z. If also set in marketplace entry, plugin.json takes precedence
• description (string): brief purpose

Optional metadata:

• author (object): { "name": "string", "email": "string", "url": "string" }
• homepage (string): URL to plugin docs
• repository (string): URL to source code
• license (string): SPDX identifier (e.g., "MIT", "Apache-2.0")
• keywords (string[]): discovery tags

Component path fields (string, string[], or inline object):

• commands — path(s) to command files. Default: ./commands/ (auto-discovered)
• agents — path(s) to agent files. Default: ./agents/ (auto-discovered)
• skills — path(s) to skill directories. Default: ./skills/ (auto-discovered)
• hooks — path to hooks config OR inline hooks object. Default: ./hooks/hooks.json
• mcpServers — path to MCP config OR inline object. Default: ./.mcp.json
• lspServers — path to LSP config. Default: ./.lsp.json
• outputStyles — path to output style definitions

If omitted, components are auto-discovered from default locations.

Command Frontmatter

Location: commands/<name>.md (auto-discovered from commands/ directory)

Required fields:

• description (string): shown in /help, must be specific and actionable

Optional fields:

• argument-hint (string): usage pattern (e.g., "<file> [--flag]")
• allowed-tools (string[]): restrict available tools. Omit for all tools
• model (string): override session model (haiku, sonnet, opus)
• user-invocable (boolean): false for shared partials in commands/shared/

Body: imperative instructions FOR Claude, not documentation TO user.

Shared Partial Frontmatter

Location: commands/shared/<name>.md

Required:

• user-invocable: false

Referenced by commands to eliminate boilerplate. Not shown in /help.

Agent Frontmatter

Location: agents/<name>.md (auto-discovered)

Official documented fields:

• name (string): agent identifier
• description (string): what the agent does and when to invoke it

Widely-used convention fields (not in official docs but used by all xiaolai plugins and numerous community plugins):

• model (string): haiku, sonnet, opus
• color (string): UI color hint — cyan, blue, magenta, yellow, green, red
• tools (string[] or comma-separated): tools available to the agent
• skills (string[]): skills loaded into context, format plugin-name:skill-name
• allowed-tools (string[]): alternative to tools

Agents can also embed inline hooks in frontmatter for PreToolUse/PostToolUse within their scope.

Body: system prompt defining mission, instructions, and output format. Best practice: include <example> blocks in description showing when/how to trigger.

Skill Structure

Location: skills/<skill-name>/SKILL.md (or skills/<plugin-name>/<skill-name>/SKILL.md)

Required frontmatter:

• name (string): skill identifier
• description (string): when/why to use — acts as trigger for auto-loading

Optional frontmatter:

• version (string): semver
• globs (string or string[]): file patterns that scope this skill

Body: reference material. Keep under 500 lines for context efficiency.

Supporting files alongside SKILL.md:

• references/ — detailed reference material
• examples/ — working code examples
• scripts/ — utility scripts

Skills in commands/ directory work identically (legacy layout). Both are auto-discovered.

Hook Events

Location: hooks/hooks.json (can have multiple files: hooks.json, security-hooks.json, etc.), inline in plugin.json hooks field, or inline in agent frontmatter.

Valid event types:

• PreToolUse — before a tool executes (can block via permission decision)
• PostToolUse — after a tool executes successfully
• PostToolUseFailure — after a tool execution fails
• PermissionRequest — when tool permission is needed
• UserPromptSubmit — when user sends a message
• Stop — when Claude stops responding
• SubagentStop — when a subagent completes
• SessionStart — when a session begins
• SessionEnd — when a session ends
• PreCompact — before context compression
• Notification — for notifications
• InstructionsLoaded — after CLAUDE.md files are loaded

Note: Event names are case-sensitive.

Hook types:

• command — run a shell command, receives JSON on stdin
• prompt — evaluate a prompt with the LLM
• agent — spawn an agentic verifier for complex verification tasks

Hook output (for command type blocking decisions):

{
  "hookSpecificOutput": {
    "permissionDecision": "allow" | "deny",
    "permissionDecisionReason": "explanation"
  }
}

Matcher: regex pattern for tool name (e.g., "Bash", "Write|Edit", "mcp__.*")

hooks.json Format

{
  "hooks": {
    "PostToolUse": [
      {
        "matcher": "Write|Edit",
        "hooks": [
          {
            "type": "command",
            "command": "${CLAUDE_PLUGIN_ROOT}/scripts/format-code.sh"
          }
        ]
      }
    ]
  }
}

Multiple hook config files are supported in the hooks/ directory.

.mcp.json Format

{
  "mcpServers": {
    "server-name": {
      "command": "executable",
      "args": ["arg1", "arg2"],
      "cwd": "${CLAUDE_PLUGIN_ROOT}",
      "env": { "KEY": "value" }
    }
  }
}

marketplace.json Format

Per-plugin marketplace (for claude plugin marketplace add):

{
  "name": "marketplace-name",
  "owner": { "name": "author-name" },
  "plugins": [
    {
      "name": "plugin-name",
      "source": { "source": "github", "repo": "owner/repo" },
      "description": "...",
      "version": "X.Y.Z",
      "author": { "name": "..." },
      "category": "developer-tools"
    }
  ]
}

owner with name is required for marketplace validation.

Source types: github, git, url, npm, file, directory, hostPattern

Plugin Directory Layout

plugin-name/
├── .claude-plugin/
│   ├── plugin.json           # manifest (name required, rest optional)
│   └── marketplace.json      # optional
├── commands/                  # auto-discovered
│   ├── command-name.md
│   └── shared/               # non-invocable partials
│       └── partial-name.md
├── agents/                    # auto-discovered
│   └── agent-name.md
├── skills/                    # auto-discovered
│   └── skill-name/
│       ├── SKILL.md
│       ├── references/        # optional
│       ├── examples/          # optional
│       └── scripts/           # optional
├── hooks/                     # can have multiple .json files
│   ├── hooks.json
│   └── security-hooks.json   # additional hook configs
├── scripts/                   # utility scripts
├── settings.json              # default plugin settings (optional)
├── .mcp.json                  # optional MCP servers
├── .lsp.json                  # optional LSP servers
├── CLAUDE.md                  # project instructions
├── README.md
└── LICENSE

${CLAUDE_PLUGIN_ROOT} resolves to the plugin's root directory at runtime. Use it in all script paths for portability.

Naming Conventions

• Plugin names: kebab-case (reading-assistant, codex-toolkit)
• Command files: kebab-case .md (audit-plugin.md)
• Agent files: kebab-case .md (qc-coordinator.md)
• Skill directories: skill-name/SKILL.md or plugin-name/skill-name/SKILL.md
• Script files: kebab-case with extension (codex-preflight.sh, parse_epub.py)

Settings

• settings.json at plugin root — default settings shipped with the plugin
• ~/.claude/settings.json — global user settings
• {project}/.claude/settings.json — project settings (committed)
• {project}/.claude/settings.local.json — local settings (gitignored)
• .claude/<plugin-name>.local.md — per-plugin config with YAML frontmatter

CLAUDE.md

• Project-level instructions for Claude Code
• Supports @ import syntax to reference other files
• Loaded from: project root, .claude/, ~/.claude/, parent directories
• Priority: closer to project root wins
• claudeMdExcludes setting can ignore specific CLAUDE.md files

Quality Standards

Commands

• Description: specific and actionable
• Steps: numbered, unambiguous, all paths covered
• Tools: match allowed-tools, least-privilege
• Output: format defined (report template)
• Errors: fallback paths specified

Agents

• Description: include <example> blocks for triggering
• Model: match task complexity (haiku mechanical, sonnet reasoning, opus judgment)
• Tools: least-privilege
• Body: mission, instructions, output format

Skills

• Description: trigger phrases matching user queries
• Body: under 500 lines, patterns over theory
• Code examples: runnable, not pseudocode
• Scope: clear boundaries, cross-references to related skills

Rules (.claude/rules/)

• YAML frontmatter: description (required), paths (optional glob array)
• Budget: <500 lines total across all rule files
• Format: bold imperative + rationale + positive framing
• Enforceable: testable, specific, observable
• No duplication of linter/formatter/CI enforcement

Scope Note

Covers Claude Code's own artifact schemas and naming conventions, and exists to inject that reference material into Codex audit prompts. For running an audit against those conventions, use $audit or $audit-fix. For authoring cc-suite advisor agents — a different, cc-suite-specific file format — use agent-design. For choosing canonical terminology inside cc-suite artifacts, use vocabulary.

Example Invocations