# Claude Craft

> Claude Code extensibility — agents, commands, hooks, skills, rules, and configuration. Use when creating, configuring, or troubleshooting Claude Code components, or when agent.md, /command, hooks.json, SKILL.md, .claude/rules, settings.json, MCP server, PreToolUse, or create agent/command/hook are mentioned.

- Skill: `outfitter-dev/claude-craft` (Agent Skill, multi-file: 41 files)
- Install (CLI): `npx skillmds@latest add outfitter-dev/claude-craft`
- Raw SKILL.md: https://api.skillmd.com/api/skills/outfitter-dev/claude-craft/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: AI & ML
- Author: outfitter-dev (https://skillmd.com/u/outfitter-dev)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/outfitter-dev/claude-craft

---


# Claude Code Extensibility

Create and configure the six Claude Code extension points: agents, commands, hooks, skills, rules, and configuration.

## Component Map

| Component    | Purpose               | Location                              | Invocation                  |
| ------------ | --------------------- | ------------------------------------- | --------------------------- |
| **Agents**   | Specialized subagents | `agents/*.md`                         | Task tool (`subagent_type`) |
| **Commands** | Reusable prompts      | `commands/*.md`                       | User: `/command-name`       |
| **Hooks**    | Event handlers        | `settings.json` or `hooks/hooks.json` | Automatic on events         |
| **Skills**   | Capability packages   | `skills/*/SKILL.md`                   | Auto-triggered by context   |
| **Rules**    | Convention files      | `.claude/rules/*.md`                  | Loaded on demand            |
| **Config**   | Settings & MCP        | `settings.json`, `.mcp.json`          | Loaded at startup           |

### Scope Hierarchy

| Scope    | Location           | Visibility   |
| -------- | ------------------ | ------------ |
| Personal | `~/.claude/`       | You only     |
| Project  | `.claude/` or root | Team via git |
| Plugin   | `<plugin>/`        | Plugin users |

## Routing

| Task                                            | Use                                     |
| ----------------------------------------------- | --------------------------------------- |
| Creating agents, commands, hooks, rules, config | This skill                              |
| Creating skills (Claude-specific features)      | This skill + `skillcraft` for base spec |
| Creating skills (cross-platform spec)           | `skillcraft`                            |
| Packaging/distributing plugins                  | `claude-plugins`                        |

---

## Agents

Specialized subagents with focused expertise, invoked via the Task tool.

### Frontmatter

```yaml
---
name: security-reviewer # Required: kebab-case, matches filename
description: | # Required: triggers + examples
  Use this agent for security vulnerability detection.
  Triggers on security audits, OWASP, injection, XSS.

  <example>
  Context: User wants security review.
  user: "Review auth code for vulnerabilities"
  assistant: "I'll use the security-reviewer agent."
  </example>
model: inherit # Optional: inherit(default)|haiku|sonnet|opus
tools: Glob, Grep, Read # Optional: comma-separated (default: inherit all)
disallowedTools: Write, Edit # Optional: deny specific tools
skills: tdd-fieldguide, debugging # Optional: auto-load skills (NOT inherited)
maxTurns: 50 # Optional: max agentic turns
memory: user # Optional: user|project|local — persistent memory
hooks: # Optional: lifecycle hooks scoped to this agent
  PreToolUse:
    - matcher: "Bash"
      hooks:
        - type: command
          command: "./scripts/validate.sh"
---
```

See [agents/frontmatter.md](references/agents/frontmatter.md) for complete schema.

### Archetypes

| Type            | Purpose                   | Typical Tools                                                              |
| --------------- | ------------------------- | -------------------------------------------------------------------------- |
| **Analyzer**    | Examine without modifying | `Glob, Grep, Read, Skill, Task, TaskCreate, TaskUpdate, TaskList, TaskGet` |
| **Implementer** | Build and modify code     | Full access (inherit)                                                      |
| **Reviewer**    | Provide feedback          | Read-only + Skill + Task tools                                             |
| **Tester**      | Create and manage tests   | Read, Write, Edit, Bash, ...                                               |
| **Researcher**  | Find and synthesize info  | ..., WebSearch, WebFetch                                                   |

See [agents/types.md](references/agents/types.md) for details.

### Model Selection

| Model     | When to Use                                    |
| --------- | ---------------------------------------------- |
| `inherit` | Recommended default — adapts to parent context |
| `haiku`   | Fast exploration, simple tasks, low-latency    |
| `sonnet`  | Balanced cost/capability (default if omitted)  |
| `opus`    | Nuanced judgment, security/architecture review |

### Tool Configuration

**Baseline** (always include when restricting):

```yaml
tools: Glob, Grep, Read, Skill, Task, TaskCreate, TaskUpdate, TaskList, TaskGet
```

Only restrict tools when there's a specific safety reason. See [agents/tools.md](references/agents/tools.md).

### Agent Body Structure

```markdown
# Agent Name

You are a [role] specializing in [expertise].

## Process

### Step 1: [Stage]

- Action items

## Output Format

Structured output spec.

## Constraints

**Always:** Required behaviors
**Never:** Prohibited actions
```

### Validation Checklist

- [ ] `name` matches filename (kebab-case, 1-3 words)
- [ ] `description` has WHAT, WHEN, triggers, 2-3 examples
- [ ] `tools` uses comma-separated valid names (case-sensitive)
- [ ] Body has clear role, process, output format, constraints

### References

| Reference                                                             | Content                              |
| --------------------------------------------------------------------- | ------------------------------------ |
| [agents/frontmatter.md](references/agents/frontmatter.md)             | YAML schema and fields               |
| [agents/types.md](references/agents/types.md)                         | Archetypes and patterns              |
| [agents/tools.md](references/agents/tools.md)                         | Tool configuration patterns          |
| [agents/discovery.md](references/agents/discovery.md)                 | How agents are found and loaded      |
| [agents/patterns.md](references/agents/patterns.md)                   | Best practices, multi-agent patterns |
| [agents/tasks.md](references/agents/tasks.md)                         | Task tool patterns                   |
| [agents/task-tool.md](references/agents/task-tool.md)                 | Task tool integration                |
| [agents/performance.md](references/agents/performance.md)             | Performance optimization             |
| [agents/advanced-features.md](references/agents/advanced-features.md) | Resumable agents, CLI config         |
| [agents/agent-vs-skill.md](references/agents/agent-vs-skill.md)       | Agents vs Skills distinction         |

---

## Commands

Custom slash commands — reusable prompts invoked by users.

### Frontmatter

```yaml
---
description: Deploy to environment with validation # Required
argument-hint: <environment> [--skip-tests] # Shown in autocomplete
allowed-tools: Bash(*), Read # Restrict tool access
model: claude-3-5-haiku-20241022 # Override model
---
```

See [commands/frontmatter.md](references/commands/frontmatter.md) for complete schema.

### Core Features

<!-- <bang> = exclamation mark; used as stand-in to avoid triggering preprocessing -->

| Feature           | Syntax                   | Purpose                         |
| ----------------- | ------------------------ | ------------------------------- |
| Arguments         | `$1`, `$2`, `$ARGUMENTS` | Dynamic input from user         |
| Bash execution    | `` <bang>`command` ``    | Include shell output in context |
| File references   | `@path/to/file`          | Include file contents           |
| Tool restrictions | `allowed-tools:`         | Limit Claude's capabilities     |

### Quick Example

```markdown
---
description: Fix a specific GitHub issue
argument-hint: <issue-number>
---

Fix issue #$1 following our coding standards.
Review the issue, implement a fix, add tests, and create a commit.
```

Usage: `/fix-issue 123`

### Argument Patterns

- **Positional**: `$1`, `$2`, `$3` — `/compare old.ts new.ts`
- **All arguments**: `$ARGUMENTS` — `/fix memory leak in auth`
- **With file refs**: `@$1` — `/analyze src/main.ts`

See [commands/arguments.md](references/commands/arguments.md) for advanced patterns.

### Scopes

| Scope    | Location              | Shows in /help |
| -------- | --------------------- | -------------- |
| Project  | `.claude/commands/`   | "(project)"    |
| Personal | `~/.claude/commands/` | "(user)"       |
| Plugin   | `<plugin>/commands/`  | Plugin name    |

Subdirectories create namespaces: `commands/frontend/component.md` → `/component`.

### Validation Checklist

- [ ] Filename is kebab-case `.md` (verb-noun pattern preferred)
- [ ] `description` is action-oriented, under 80 chars
- [ ] `argument-hint` uses `<required>` and `[optional]` syntax
- [ ] `allowed-tools` uses correct case-sensitive names
- [ ] Bash commands tested in terminal first

### References

| Reference                                                             | Content                     |
| --------------------------------------------------------------------- | --------------------------- |
| [commands/frontmatter.md](references/commands/frontmatter.md)         | Complete frontmatter schema |
| [commands/arguments.md](references/commands/arguments.md)             | Argument handling patterns  |
| [commands/bash-execution.md](references/commands/bash-execution.md)   | Shell command execution     |
| [commands/file-references.md](references/commands/file-references.md) | File inclusion syntax       |
| [commands/permissions.md](references/commands/permissions.md)         | Tool restriction patterns   |
| [commands/namespacing.md](references/commands/namespacing.md)         | Directory organization      |
| [commands/sdk-integration.md](references/commands/sdk-integration.md) | Agent SDK usage             |
| [commands/community.md](references/commands/community.md)             | Community examples          |

---

## Hooks

Event handlers that automate workflows, validate operations, and respond to Claude Code events.

### Hook Types

| Type        | Best For                                      | Response Format                                  | Default Timeout |
| ----------- | --------------------------------------------- | ------------------------------------------------ | --------------- |
| **command** | Deterministic checks, external tools          | Exit codes + JSON                                | 600s            |
| **prompt**  | Complex reasoning, context-aware validation   | `{"ok": bool, "reason": "..."}`                  | 30s             |
| **agent**   | Multi-step verification requiring tool access | `{"ok": bool, "reason": "..."}` (up to 50 turns) | 60s             |

**Prompt hooks**: Send prompt + hook input to a Claude model (Haiku by default, override with `model` field). Return `{"ok": true}` to proceed or `{"ok": false, "reason": "..."}` to block.

**Agent hooks**: Spawn a subagent with tool access (`allowedTools`) for multi-step verification. Same `ok`/`reason` response format as prompt hooks.

### Events

| Event                  | When                        | Can Block | Matcher           | Common Uses                     |
| ---------------------- | --------------------------- | --------- | ----------------- | ------------------------------- |
| **PreToolUse**         | Before tool executes        | Yes       | Tool name         | Validate commands, check paths  |
| **PostToolUse**        | After tool succeeds         | No        | Tool name         | Auto-format, run linters        |
| **PostToolUseFailure** | After tool fails            | No        | Tool name         | Error logging, retry logic      |
| **PermissionRequest**  | Permission dialog shown     | Yes       | Tool name         | Auto-allow/deny rules           |
| **UserPromptSubmit**   | User submits prompt         | No        | (none)            | Add context, log activity       |
| **Notification**       | Claude sends notification   | No        | Notification type | External alerts, desktop notify |
| **Stop**               | Claude finishes responding  | No        | (none)            | Cleanup, verify completion      |
| **SubagentStart**      | Subagent spawns             | No        | Agent type        | Track spawning, setup resources |
| **SubagentStop**       | Subagent finishes           | No        | Agent type        | Log results, trigger follow-ups |
| **TeammateIdle**       | Team agent about to idle    | No        | (none)            | Coordination, reassignment      |
| **TaskCompleted**      | Task marked completed       | No        | (none)            | Validation, notifications       |
| **Setup**              | `--init` or `--maintenance` | No        | (none)            | Initialize environment          |
| **PreCompact**         | Before context compaction   | No        | Trigger type      | Backup conversation             |
| **SessionStart**       | Session starts/resumes      | No        | Start reason      | Load context, show status       |
| **SessionEnd**         | Session ends                | No        | End reason        | Cleanup, save state             |

See [hooks/hook-types.md](references/hooks/hook-types.md) for detailed per-event documentation.

### Configuration Format

```json
{
  "hooks": {
    "PreToolUse": [
      {
        "matcher": "Write|Edit(*.ts|*.tsx)",
        "hooks": [
          {
            "type": "command",
            "command": "bunx ultracite fix \"$file\"",
            "timeout": 10
          }
        ]
      }
    ]
  }
}
```

| Location                      | Scope            | Format                                              |
| ----------------------------- | ---------------- | --------------------------------------------------- |
| `.claude/settings.json`       | Project (shared) | Direct `"hooks"` key                                |
| `.claude/settings.local.json` | Project (local)  | Direct `"hooks"` key                                |
| `~/.claude/settings.json`     | Personal         | Direct `"hooks"` key                                |
| `<plugin>/hooks/hooks.json`   | Plugin           | Wrapped in `{"description": "...", "hooks": {...}}` |

### Matchers

```json
{"matcher": "Write"}                    // Exact match
{"matcher": "Edit|Write"}               // Multiple tools (OR)
{"matcher": "*"}                        // All tools
{"matcher": "Write(*.py)"}              // File pattern
{"matcher": "Write|Edit(*.ts|*.tsx)"}   // Multiple + pattern
{"matcher": "mcp__memory__.*"}          // MCP server tools
```

Lifecycle event matchers:

- **SessionStart**: `startup`, `resume`, `clear`, `compact`
- **SessionEnd**: `clear`, `logout`, `prompt_input_exit`, `bypass_permissions_disabled`, `other`
- **Notification**: `permission_prompt`, `idle_prompt`, `auth_success`, `elicitation_dialog`
- **SubagentStart/Stop**: Agent type name (e.g., `Explore`, `Plan`, `db-agent`)
- **PreCompact**: `manual`, `auto`

See [hooks/matchers.md](references/hooks/matchers.md) for advanced patterns.

### Exit Codes

| Code  | Meaning                                                   |
| ----- | --------------------------------------------------------- |
| `0`   | Success, continue execution                               |
| `2`   | Block operation (PreToolUse only), stderr shown to Claude |
| Other | Warning, stderr shown to user, continues                  |

### JSON Output (Advanced)

```json
{
  "continue": true,
  "suppressOutput": false,
  "systemMessage": "Context for Claude",
  "hookSpecificOutput": {
    "hookEventName": "PreToolUse",
    "permissionDecision": "allow|deny|ask",
    "permissionDecisionReason": "Explanation",
    "updatedInput": { "modified": "field" }
  }
}
```

### Execution Model

All matching hooks run **in parallel** (not sequentially). Identical handlers are automatically deduplicated. Design hooks to be independent — they cannot see each other's output.

**Hot-swap**: Hooks added via `/hooks` menu take effect immediately. Manual edits to settings files require a session restart or `/hooks` menu visit.

**Stop hooks**: Fire whenever Claude finishes responding, not only at task completion. Do NOT fire on user interrupts. To prevent infinite loops, check `stop_hook_active` in the input JSON and exit early if `true`.

### Component-Scoped Hooks

Skills, agents, and commands can define hooks in frontmatter. All hook events are supported. `Stop` hooks in agent/skill frontmatter are automatically converted to `SubagentStop` events at runtime.

```yaml
---
name: my-skill
hooks:
  PreToolUse:
    - matcher: "Write|Edit"
      hooks:
        - type: prompt
          prompt: "Validate this write operation..."
  Stop: # Converted to SubagentStop at runtime
    - hooks:
        - type: command
          command: "./scripts/on-complete.sh"
---
```

### Environment Variables

| Variable                | Availability             | Description                           |
| ----------------------- | ------------------------ | ------------------------------------- |
| `$CLAUDE_PROJECT_DIR`   | All hooks                | Project root directory                |
| `${CLAUDE_PLUGIN_ROOT}` | Plugin hooks             | Plugin root (use for portable paths)  |
| `$file`                 | PostToolUse (Write/Edit) | Path to affected file                 |
| `$CLAUDE_ENV_FILE`      | SessionStart             | Write env vars to persist for session |
| `$CLAUDE_CODE_REMOTE`   | All hooks                | Set if running in remote context      |

### Validation Checklist

- [ ] Hook scripts are executable (`chmod +x`)
- [ ] Matchers use correct case-sensitive tool names
- [ ] Timeouts set (default: 600s command, 30s prompt, 60s agent; max: 10 minutes)
- [ ] Scripts use `set -euo pipefail` and quote variables
- [ ] Plugin hooks use `${CLAUDE_PLUGIN_ROOT}` for paths

### References

| Reference                                             | Content                       |
| ----------------------------------------------------- | ----------------------------- |
| [hooks/hook-types.md](references/hooks/hook-types.md) | Per-event documentation       |
| [hooks/matchers.md](references/hooks/matchers.md)     | Advanced matcher patterns     |
| [hooks/schema.md](references/hooks/schema.md)         | Complete configuration schema |
| [hooks/security.md](references/hooks/security.md)     | Security best practices       |
| [hooks/examples.md](references/hooks/examples.md)     | Real-world implementations    |

---

## Skills (Claude-Specific)

Claude Code extends the base [Agent Skills specification](https://agentskills.io/specification) with additional features. For the cross-platform spec, load `skillcraft`.

### Frontmatter Extensions

| Field                      | Type    | Description                                                   |
| -------------------------- | ------- | ------------------------------------------------------------- |
| `allowed-tools`            | string  | Space-separated tools that run without permission prompts     |
| `user-invocable`           | boolean | Default `true`. Set `false` to prevent `/skill-name` access   |
| `disable-model-invocation` | boolean | Prevents auto-activation; requires manual Skill tool          |
| `context`                  | string  | `inherit` (default) or `fork` for isolated subagent execution |
| `agent`                    | string  | Agent for `context: fork` (e.g., `Explore`, `analyst`)        |
| `model`                    | string  | Override model: `haiku`, `sonnet`, or `opus`                  |
| `hooks`                    | object  | Lifecycle hooks active while skill loaded                     |
| `argument-hint`            | string  | Hint shown after `/skill-name` (e.g., `[file path]`)          |

### Tool Restrictions

```yaml
# Space-separated list
allowed-tools: Read Grep Glob

# With Bash patterns
allowed-tools: Read Write Bash(git *) Bash(npm run *)

# MCP tools (double underscore format)
allowed-tools: Read mcp__linear__create_issue
```

Tool names are case-sensitive. See [skills/integration.md](references/skills/integration.md) for patterns.

### String Substitutions

| Pattern                 | Replaced With                  |
| ----------------------- | ------------------------------ |
| `$ARGUMENTS`            | User input after `/skill-name` |
| `${CLAUDE_SESSION_ID}`  | Current session identifier     |
| `${CLAUDE_PLUGIN_ROOT}` | Plugin root directory path     |

### Context Modes

- **`inherit`** (default): Runs in main conversation with full history access
- **`fork`**: Runs in isolated subagent context; prevents context pollution

```yaml
context: fork
agent: analyst
model: haiku
```

See [skills/context-modes.md](references/skills/context-modes.md) for patterns.

### References

| Reference                                                                   | Content                          |
| --------------------------------------------------------------------------- | -------------------------------- |
| [skills/context-modes.md](references/skills/context-modes.md)               | Fork vs inherit patterns         |
| [skills/integration.md](references/skills/integration.md)                   | Commands, hooks, MCP integration |
| [skills/performance.md](references/skills/performance.md)                   | Token impact, optimization       |
| [skills/preprocessing-safety.md](references/skills/preprocessing-safety.md) | Safe preprocessing patterns      |

---

## Preprocessing

<!-- <bang> = exclamation mark; used as stand-in to avoid triggering preprocessing -->

Claude Code preprocesses `` <bang>`command` `` syntax — executing shell commands and injecting output before content reaches Claude. This powers live context in commands (git state, PR details, environment info).

**Critical**: Preprocessing runs in both command files AND SKILL.md files, including inside markdown code fences. There is no escape mechanism.

### Where preprocessing runs

| Context                         | Preprocessed | Safe to use literal `!`?         |
| ------------------------------- | ------------ | -------------------------------- |
| Command files (`commands/*.md`) | Yes          | Yes — intentional                |
| SKILL.md                        | Yes          | No — use `<bang>` instead        |
| References, EXAMPLES.md         | No           | Yes — great for copy-paste demos |
| Rules, CLAUDE.md, agents        | No           | Yes                              |

### Writing SKILL.md files

When documenting or referencing the preprocessing syntax in a SKILL.md, use `<bang>` as a stand-in for `!`. Agents interpret `<bang>` as `!`.

Add an HTML comment explaining the convention:

```html
<!-- <bang> = exclamation mark; used as stand-in to avoid triggering preprocessing -->
```

Then use `<bang>` for any inline references:

- `` <bang>`git status` `` — injects current git status
- `` <bang>`gh pr view --json title` `` — injects PR details

Move real copy-paste examples with literal `!` to reference files — those are not preprocessed.

### Writing reference files

Reference files (`references/`, `EXAMPLES.md`) are not preprocessed. Use literal `!` freely — these serve as copy-paste sources for command authors:

See [commands/bash-execution.md](references/commands/bash-execution.md) for the full reference with real `!` syntax.

### Intentional preprocessing in skills

Skills that genuinely run commands at load time should declare it in frontmatter:

```yaml
metadata:
  preprocess: true
```

### Validation

Run `/skillcheck` to scan SKILL.md files for unintentional preprocessing patterns. The linter respects `metadata.preprocess: true` and skips intentional uses.

See [skills/preprocessing-safety.md](references/skills/preprocessing-safety.md) for detailed examples, common mistakes, and the full convention.

---

## Rules

Reusable convention files in `.claude/rules/` for project patterns.

### Rules vs CLAUDE.md

| Aspect  | CLAUDE.md                   | .claude/rules/          |
| ------- | --------------------------- | ----------------------- |
| Loading | Automatic at session start  | On-demand via reference |
| Content | Project setup, key commands | Reusable conventions    |
| Size    | Concise (~200-500 lines)    | Can be detailed         |

**CLAUDE.md**: One-off instructions, project commands, key file locations.
**rules/**: Formatting conventions, architecture patterns, workflow guidelines.

### File Conventions

- **UPPERCASE.md** — All caps with `.md` extension
- **Topic-focused** — One concern per file
- **Kebab-case** for multi-word: `API-PATTERNS.md`, `CODE-REVIEW.md`

### Path-Specific Rules

```yaml
---
paths:
  - "src/api/**/*.ts"
  - "lib/**/*.ts"
---
# API Development Rules
```

### Referencing Rules

Rules are NOT auto-loaded. Reference from CLAUDE.md:

```markdown
# CLAUDE.md

Follow `.claude/rules/FORMATTING.md` for all code conventions.
```

Or use `@` syntax: `@./project-specific/FORMATTING.md`

See [rules.md](references/rules.md) for detailed patterns and anti-patterns.

---

## Configuration

### File Locations

| Scope            | Settings                      | MCP              |
| ---------------- | ----------------------------- | ---------------- |
| Personal         | `~/.claude/settings.json`     | `~/.claude.json` |
| Project (shared) | `.claude/settings.json`       | `.mcp.json`      |
| Project (local)  | `.claude/settings.local.json` | —                |
| Managed (org)    | System-level path             | —                |

Precedence (highest first): Managed > CLI args > Local > Project > User.

### MCP Server Setup

**Project MCP** (`.mcp.json`):

```json
{
  "mcpServers": {
    "github": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-github"],
      "env": { "GITHUB_TOKEN": "${GITHUB_TOKEN}" }
    }
  }
}
```

**Personal MCP** (`~/.claude.json`):

```json
{
  "mcp_servers": {
    "memory": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-memory"]
    }
  }
}
```

### Key Settings

```json
{
  "$schema": "https://json.schemastore.org/claude-code-settings.json",
  "permissions": {
    "allow": ["Bash(npm run lint)"],
    "deny": ["Read(./.env)"],
    "defaultMode": "acceptEdits"
  },
  "hooks": {},
  "enabledPlugins": { "plugin@marketplace": true },
  "model": "claude-sonnet-4-5-20250929"
}
```

See [config/mcp-patterns.md](references/config/mcp-patterns.md), [config/workflows.md](references/config/workflows.md), and [config/troubleshooting.md](references/config/troubleshooting.md) for details.

---

## Testing & Debugging

```bash
# Debug mode — shows skill/agent/hook loading details
claude --debug

# Force reload after changes
/clear

# Test hook manually
echo '{"tool_name": "Write", "tool_input": {"file_path": "test.ts"}}' | ./hooks/my-hook.sh

# Verify commands appear
/help
```

---

## External Resources

- [Claude Code Docs — Hooks](https://code.claude.com/docs/en/hooks)
- [Claude Code Docs — Memory](https://code.claude.com/docs/en/memory)
- [Claude Code Docs — Settings](https://code.claude.com/docs/en/settings)
- [Hooks Guide](https://code.claude.com/docs/en/hooks-guide)
- [Agent Skills Spec](https://agentskills.io/specification)