conventions-claude

Claude Code Conventions

Tool-specific overlay for Claude Code plugin artifacts. Loaded by the scorer and checker when an artifact is classified as Tier 2-Claude (per agents/scorer.md step 3). The universal floor lives in nlpm:conventions; this overlay adds Claude-Code-specific schemas on top.

Primary authoritative sources:

• https://code.claude.com/docs/en/claude_code_docs_map.md
• https://code.claude.com/docs/en/skills.md
• https://code.claude.com/docs/en/hooks.md
• https://code.claude.com/docs/en/plugins.md
• https://code.claude.com/docs/en/plugins-reference.md
• https://code.claude.com/docs/en/sub-agents.md
• https://code.claude.com/docs/en/settings.md
• https://code.claude.com/docs/en/memory.md
• https://code.claude.com/docs/en/slash-commands.md
• https://code.claude.com/docs/en/tools-reference.md — authoritative built-in tool catalog (see §16)
• https://code.claude.com/docs/en/plugin-marketplaces.md

---

1. .claude-plugin/plugin.json

The plugin manifest.

Required fields:

• name — string, kebab-case, unique identifier

The manifest is fully optional — components auto-discover from conventional paths, and only name is required when present. Unrecognized top-level fields are ignored with a warning (error only under claude plugin validate --strict).

Optional fields:

• version — semver string (e.g. "0.1.0"). If omitted, commit SHA is used (every commit = new version). For stable releases, set explicit semver.
• description — one-line summary
• displayName — human-readable name shown in installer UI (v2.1.143+)
• author — object: { "name": "...", "email": "...", "url": "..." }
• homepage — URL string
• repository — URL string or object
• license — SPDX identifier
• keywords — string array for discovery
• $schema — URL to the manifest JSON Schema (editor validation)
• defaultEnabled — boolean; whether the plugin is enabled on install (v2.1.154+)
• userConfig — object; per-key prompts shown to the user at enable time; values exposed as ${user_config.<key>} substitutions
• channels — array; message-injection channel bindings
• dependencies — array of other plugins this one requires (supports semver constraints)

NOT plugin.json fields (common mistake):

• agent — this is a settings.json default key (a plugin's bundled settings.json supports only agent and subagentStatusLine), not a manifest field.
• category — belongs to a marketplace.json plugin entry, not the manifest.

Component path fields (all optional, string or string[]):

• commands — path(s) to command markdown files
• agents — path(s) to agent markdown files
• skills — path(s) to skill directories
• hooks — path to hooks.json
• mcpServers — path(s) to MCP server config
• lspServers — path(s) to LSP server config (stable in 2026; schema in §12)
• outputStyles — path(s) to output style definitions
• experimental.themes — path(s) to theme definitions (was top-level themes; now nested under experimental)
• experimental.monitors — path(s) to monitor config (was top-level monitors; schema in §13). Top-level still works but claude plugin validate warns; a future release will require the experimental.* form.

Example:

{
  "name": "my-plugin",
  "version": "0.2.1",
  "description": "Does useful things",
  "author": { "name": "dev" },
  "license": "MIT",
  "keywords": ["tools", "productivity"],
  "commands": "commands/",
  "agents": "agents/",
  "skills": "skills/"
}

---

2. Commands and Skills — merged surfaces (v2.1.x change)

Critical: as of Claude Code v2.1.x, commands and skills are the same architecture. Both surfaces support the same frontmatter and execution semantics. The recommended canonical path is:

.claude/skills/<name>/SKILL.md     # preferred for new development
.claude/commands/<name>.md         # still works; equivalent behavior

Existing .claude/commands/ files continue to function. New code should prefer the skill layout because it allows companion files (scripts/, references/, examples/) in the same directory.

Authoritative reference: https://code.claude.com/docs/en/slash-commands

2.1 Frontmatter (shared between commands and skills)

Required:

• description — string; explains what it does and when to invoke. Combined with when_to_use: if present.

Optional (universal):

• name — string; per official docs, explicitly optional. When omitted, filename or enclosing directory is used. Pre-v0.7.15 nlpm incorrectly flagged missing name: as a bug; corrected after Jeffallan/claude-skills#184 maintainer feedback.
• argument-hint — string; placeholder shown in UI (e.g., "[path]")
• arguments — space-separated or YAML list of named arguments for $name substitution (e.g., "issue branch")
• allowed-tools — string array OR space-separated string; pre-approved tools (no per-use prompt). Format: "Read Grep Bash(git *)" or ["Read", "Grep"].
• disallowed-tools — string array OR space-separated string; tools removed from the pool while the skill is active.
• model — haiku / sonnet / opus / a full model ID / inherit (keep the active model); overrides session model for one turn.
• effort — low / medium / high / xhigh / max; overrides session effort.
• user-invocable — boolean; false hides from menu (only Claude invokes).
• disable-model-invocation — boolean; true means only the user invokes (manual /skill-name only).

Optional (v2.1.x additions — NEW since pre-2026 conventions):

• when_to_use — string; additional trigger hints (appends to description)
• context — "fork" runs in a forked subagent (isolates from main history)
• agent — which subagent type (built-in: Explore, Plan, general-purpose)
• hooks — {...} skill-scoped hooks (same shape as settings.json hooks)
• paths — glob patterns; auto-load only for matching files (e.g., "src/**/*.ts,lib/**/*.ts")
• shell — bash (default) or powershell for !cmd`` blocks

2.2 Body conventions

• Write imperative instructions directed at Claude (not the user)
• Use numbered steps for multi-phase workflows
• Reference shared partials by relative path: commands/shared/name.md
• Define expected output format explicitly in the body

2.3 Dynamic context injection

• !`git diff HEAD` — runs command before Claude sees the skill; replaces line with output.
• ```! fenced blocks — multi-line commands.
• Disabled if "disableSkillShellExecution": true in settings.

2.4 String substitutions (valid in command/skill bodies)

$ARGUMENTS, $ARGUMENTS[N], $N (positional), $name (named argument), ${CLAUDE_SESSION_ID}, ${CLAUDE_EFFORT}, ${CLAUDE_SKILL_DIR}, ${CLAUDE_PLUGIN_ROOT}. Do NOT flag these as undefined variables.

---

3. Shared Partials

Reusable command fragments located in commands/shared/.

Rules:

• MUST include user-invocable: false in frontmatter — prevents appearing as top-level commands
• MUST have a description stating their purpose as a partial
• Referenced by full relative path from the consuming command file
• Can contain any mix of instructions, templates, or decision logic

---

4. Agent Frontmatter

Agents live in .claude/agents/<name>.md.

The system prompt is the markdown body of the file (in --agents JSON form it is the prompt key). There is no system-prompt frontmatter key — flagging or recommending one is a bug (corrected 2026-06-07 against sub-agents.md).

Documented fields:

• name — string; identifier for invocation
• description — string; critical for reliable triggering — should contain 3+ specific phrases describing when to use this agent
• tools — tools the agent body uses; two valid formats:
  • JSON array: tools: ["Read", "Glob"]
  • Comma-separated string: tools: Read, Glob, Grep
• disallowedTools — tools removed from the inherited pool (this is the correct key — there is no tool-restrictions: {allow, deny} key; the old nlpm name was wrong)
• model — haiku / sonnet / opus / a full ID (e.g. claude-opus-4-8) / inherit; defaults to inherit
• skills — preload skill content into this agent's context at startup. Two valid formats:
  • JSON array: skills: ["nlpm:conventions"]
  • YAML list: skills:\n - nlpm:conventions

Convention / additional fields:

• effort — low / medium / high / xhigh / max
• color — one of red, blue, green, yellow, purple, orange, pink, cyan; visual label. magenta is NOT valid (old nlpm list had it; the current valid set adds purple, orange, pink).
• permissionMode — default / acceptEdits / auto / dontAsk / bypassPermissions / plan
• isolation — only valid value "worktree" (runs the agent in a git worktree)
• memory — user / project / local
• maxTurns — integer turn cap
• background — boolean; run asynchronously
• initialPrompt — string; seeds the agent's first turn
• mcpServers, hooks — agent-scoped overrides

Plugin-shipped agents are restricted: hooks, mcpServers, and permissionMode are ignored for agents distributed inside a plugin (security). Score plugin agents accordingly.

Best practice: include <example> blocks in description. Two or more <example> blocks with diverse scenarios is the minimum for reliable triggering.

---

5. Skills — Claude Code path conventions

Universal SKILL.md spec lives in nlpm:conventions (open spec at agentskills.io). Claude Code uses these path conventions:

• Single plugin skill: skills/<name>/SKILL.md
• Multi-skill plugin: skills/<plugin>/<name>/SKILL.md
• Project-scoped: .claude/skills/<name>/SKILL.md
• User-scoped: ~/.claude/skills/<name>/SKILL.md

Skill discovery paths now support parent-directory and monorepo nested scanning (v2.1.x). Skills from ./parent/.claude/skills/ and ./packages/frontend/.claude/skills/ auto-load. Skills from --add-dir paths also load from .claude/skills/ within added directories.

Supporting files: Same directory as SKILL.md — scripts/, references/, examples/, etc. Reference them from SKILL.md so Claude knows when to load them.

Skill preloading in agents (v2.1.x): Declare skills: [name1, name2] in agent frontmatter to inject full skill content at startup (vs. Claude auto-loading on demand).

---

6. Rules

Rules live in .claude/rules/<name>.md.

Frontmatter:

• description — string (required)
• paths — string array (optional); glob patterns scoping which files this rule applies to

Body format:

• Lead with a bold imperative: **Always do X.** or **Use Y instead of Z.**
• Follow immediately with rationale
• Be specific and testable
• State what to DO, not only what to avoid (Pink Elephant effect)

Budget: Under 500 lines total per rules file.

Naming convention for ordered sets: NN-kebab-name.md (e.g. 01-formatting.md).

---

7. Hook Events (Claude Code)

Hook events are case-sensitive. Using wrong case silently ignores the hook.

Confirmed against 2026-06-07 docs refresh (hooks.md):

Event	Trigger	Context fields
SessionStart	Session begin	source (startup/resume/clear/compact), model
SessionEnd	Session end	(trigger only)
UserPromptSubmit	User submits a prompt	prompt text
PreToolUse	Before any tool call	tool_name, tool_input
PostToolUse	After tool call	tool_name, tool_input, tool_output
PermissionRequest	When Claude requests permission	tool_name, tool_input, permission_mode
Stop	Once per turn	reason (can set decision: block to prevent stopping)
StopFailure	Once per turn — Claude failed to complete	reason
FileChanged	Per file change	filename, watcher_path

Now confirmed real (were "uncertain" in v0.1.0 — resolved 2026-06-07): SubagentStop, PreCompact, Notification, PostToolUseFailure, InstructionsLoaded, TaskCompleted (exact spelling — not TaskComplete). These are valid events; do NOT flag them as unknown.

Additional current events (add to the known-event allow-list): Setup, SubagentStart, UserPromptExpansion, PermissionDenied, PostToolBatch, MessageDisplay, TaskCreated, TeammateIdle, ConfigChange, CwdChanged, WorktreeCreate, WorktreeRemove, PostCompact, Elicitation, ElicitationResult. Any string matching a documented event name is valid regardless of whether it post-dates this doc — when in doubt, verify against code.claude.com/docs/en/hooks.md rather than penalizing.

Hook types (canonical, all lowercase in JSON):

• command — shell script (stdin/stdout)
• http — HTTP POST endpoint
• mcp_tool — MCP server tool invocation
• prompt — LLM evaluation
• agent — subagent verification

A command hook may add "shell": "powershell" to run that hook in PowerShell instead of the default shell.

Matcher patterns: string (exact), pipe-separated list (Bash|Edit), or regex (non-alphanumeric chars).

MCP tool naming: mcp__<server>__<tool> (e.g., mcp__memory__write.*). Hook matchers use this format.

Exit codes (command hooks):

• 0 — success (stdout to debug log; for UserPromptSubmit, UserPromptExpansion, and SessionStart, stdout is injected as context)
• 2 — blocking error (action denied, stderr fed to Claude) — only on blockable events. Non-blockable events ignore exit 2: PostToolUse, PostToolUseFailure, Notification, SessionStart, SessionEnd, InstructionsLoaded, StopFailure, MessageDisplay.
• 1, 3+ — non-blocking error (logged in debug only)

---

8. hooks.json Format

Located at .claude/hooks.json or <plugin>/hooks/hooks.json.

{
  "hooks": {
    "PreToolUse": [
      {
        "matcher": "Write|Edit",
        "hooks": [
          {
            "type": "command",
            "command": "${CLAUDE_PLUGIN_ROOT}/scripts/pre-write-check.sh"
          }
        ]
      }
    ],
    "SessionStart": [
      {
        "matcher": "",
        "hooks": [
          {
            "type": "prompt",
            "prompt": "You are now in strict TDD mode."
          }
        ]
      }
    ]
  }
}

Structure rules:

• Top-level key: "hooks"
• Second-level keys: event names (case-sensitive)
• Each event maps to an array of matcher objects: { "matcher": "<regex>", "hooks": [...] }
• Each hook object: { "type": "command"|"http"|"mcp_tool"|"prompt"|"agent", "<type-field>": "..." }
• Field name matches the type: "command" for type command, "prompt" for type prompt, etc.

---

9. .mcp.json

Claude Code reads MCP server registrations from a standalone JSON file at the repo root (NOT embedded in settings.json like Gemini, NOT inside config.toml like Codex).

{
  "mcpServers": {
    "my-server": {
      "type": "stdio",
      "command": "node",
      "args": ["./server.js"]
    }
  }
}

Plugin scope: <plugin>/.claude-plugin/.mcp.json or <plugin>/.mcp.json (path per plugin.json).

---

10. CLAUDE.md (memory file)

Project-scoped: CLAUDE.md at repo root, plus optional .claude/memory/*.md. User-scoped: ~/.claude/CLAUDE.md.

Recommended pattern for multi-tool projects (per analysis/multi-tool-design-2026-05.md decision #5): use a one-line CLAUDE.md that imports AGENTS.md:

@AGENTS.md

This makes AGENTS.md the canonical universal memory file. AGENTS.md is what Codex reads natively; Gemini/Antigravity can be configured to read it via context.fileName array. This is how nlpm itself works.

Body conventions when content lives in CLAUDE.md directly:

• Build/run instructions
• Test commands
• Architecture overview (what lives where)
• Prerequisites section
• Valid @-imports must reference existing files

---

11. .claude/settings.json and .claude/settings.local.json

Field	Purpose
permissions	Permission policy (allow/deny rules, modes); incl. permissions.additionalDirectories
hooks	Hook event registrations (alternative to hooks/hooks.json for project-scoped hooks)
model	Default model selection
disableSkillShellExecution	If true, disables !...`` and ```! dynamic blocks in skills
env	Environment variables injected into the session
statusLine	Custom status line command/config
agent	Default agent (also the only default-settings key, besides subagentStatusLine, a plugin may set)
effortLevel	Default effort
language, outputStyle	Locale / output style defaults
enabledPlugins	Plugins enabled for the project
claudeMd, claudeMdExcludes	Extra memory file globs / exclusions
autoMemoryEnabled, autoMemoryDirectory	Auto-memory toggle + location (see §15)
sandbox.enabled	Sandbox execution toggle
extraKnownMarketplaces, strictKnownMarketplaces	Marketplace trust config

theme is not a documented settings.json field — do not flag its absence or treat it as valid here (removed from this list 2026-06-07). The above is representative, not exhaustive; treat unrecognized-but-plausible keys as advisory, not errors.

Rule: .local.json is gitignored (per-user); the non-local file is shared. NEVER set bypassPermissions: true in the shared file.

---

12. LSP Servers (.lsp.json)

Stable in 2026 (was experimental in 2025). .lsp.json file, or a lspServers object in plugin.json. Required fields command + extensionToLanguage. Full per-server schema → reference.md.

---

13. Monitors (monitors/monitors.json)

Stable in 2026 (was experimental in 2025). Plugin background watchers; requires v2.1.105+; inline via experimental.monitors (§1). Per-entry required name + command + description. Full schema → reference.md.

---

14. Reference Syntax

Commands referencing shared partials:

<!-- Include: commands/shared/discover.md -->

Or by instruction: "Follow the steps in commands/shared/discover.md"

Agents referencing skills in frontmatter:

skills: ["nlpm:conventions", "nlpm:conventions-claude"]

Hooks referencing scripts:

"command": "${CLAUDE_PLUGIN_ROOT}/scripts/check.sh"

Always use ${CLAUDE_PLUGIN_ROOT} for intra-plugin file references. Hardcoded absolute paths break portability.

Cross-plugin skill references use the same plugin:skill format. The plugin must be installed for the reference to resolve.

---

15. Memory File Conventions (~/.claude/projects/<slug>/memory/)

Claude Code writes per-project persistent memory at ~/.claude/projects/<project-slug>/memory/ ("Auto memory", v2.1.59+). Toggled by autoMemoryEnabled; location overridable via autoMemoryDirectory (§11). At session start the first ~200 lines / 25 KB of MEMORY.md plus topic files are loaded into context.

Index file: MEMORY.md (no frontmatter; one-line-per-entry index).

Individual memory files MUST include YAML frontmatter:

---
name: "short identifier"
description: "one-line summary"
type: user | feedback | project | reference
---

type values:

Value	Meaning
user	Preferences, habits, or facts about the user
feedback	Corrections or lessons from past sessions
project	Project-specific facts, decisions, or context
reference	External reference material copied into memory

Rules:

• Every memory file must appear in MEMORY.md (orphans are flagged).
• MEMORY.md itself is the index; not scored as a memory file.
• Memory files should not reference removed files or functions.

---

16. Claude Code Tool Catalog

Tool names valid in tools:, allowed-tools:, disallowed-tools:. Never flag a well-formed tool name as "unknown" or "undocumented" — the catalog grows and any string matching Pascal-name or mcp__<server>__<tool> patterns is valid. Key renames: Task → Agent (alias kept); MultiEdit, BashOutput, KillBash removed; TodoWrite default-off (→ Task* family); SlashCommand folded into Skill.

Full catalog — built-in tools, renames/removals, MCP naming → reference.md. Authoritative source: code.claude.com/docs/en/tools-reference.md.

---

17. Plugin distribution

Marketplace manifest: .claude-plugin/marketplace.json at the marketplace repo root. Schema:

{
  "name": "marketplace-name",
  "plugins": [
    {
      "name": "plugin-name",
      "source": {
        "source": "github",
        "repo": "owner/repo"
      },
      "description": "...",
      "version": "1.0.0",
      "author": { "name": "..." },
      "repository": "https://github.com/owner/repo",
      "license": "MIT",
      "category": "developer-tools"
    }
  ]
}

Plugin from URL (v2.1.x): --plugin-url and --plugin-dir flags accept .zip archives.

Namespacing: Skills are namespaced (/my-plugin:hello). Commands and agents use short names. Prevents conflicts between plugins.

---

18. Scope and uncertainty

This skill covers Claude Code conventions. It does NOT cover:

• Universal SKILL.md spec → nlpm:conventions
• Penalty tables → nlpm:scoring

Resolved in the 2026-06-07 refresh (no longer uncertain):

• The six previously-uncertain hook events are confirmed real (§7).
• LSP server schema (.lsp.json) — now documented (§12).
• Monitor schema (monitors/monitors.json) — now documented (§13).

Still approximate (verify before citing a specific tag):

• Exact version-gate tags (e.g. v2.1.142 for TodoWrite default-off, v2.1.154 for defaultEnabled) came from a summarizing fetch; the change is confirmed, the precise version is approximate.
• userConfig / channels / dependencies plugin.json field shapes are listed but not field-by-field enumerated here.
• plugin-marketplaces.md full field schema not yet folded into §17.