docs: document Claude Code 2.1.0 schema changes

- skills.md: context, agent, user-invocable, hooks fields
- commands.md: hooks field for command-scoped lifecycle hooks
- settings.md: language, respectGitignore, once, new hook types
- schema-constraints.md: new rules for all v2.1.0 fields

Author: Test User

docs/rules/commands.md

@@ -279,6 +279,36 @@ cclint observation (documentation best practice)
 
 ---
 
+## New Frontmatter Fields (v2.1.0+)
+
+Claude Code 2.1.0 introduced the `hooks` field for commands:
+
+| Field | Type | Description |
+|-------|------|-------------|
+| `hooks` | object | Lifecycle hooks scoped to command execution |
+
+### Example with Hooks
+
+```yaml
+---
+name: my-command
+description: Example command with hooks
+hooks:
+  PreToolUse:
+    - matcher: "Write"
+      hooks:
+        - type: command
+          command: echo "Before write"
+          once: true
+  Stop:
+    - hooks:
+        - type: command
+          command: echo "Command finished"
+---
+```
+
+---
+
 ## Summary
 
 | Rule Range | Category | Count |

docs/rules/schema-constraints.md

@@ -302,6 +302,119 @@ Command model field must be one of the predefined Claude Code model identifiers.
 
 ---
 
+### Rule 117a: Command Hooks Field (v2.1.0+)
+
+**Severity:** info
+**Component:** command
+**Category:** schema
+
+**Description:**
+Commands can define lifecycle hooks (PreToolUse, PostToolUse, Stop) scoped to the command's execution.
+
+**Constraint:**
+```
+hooks?: {
+	[string]: [...#CommandHook]
+}
+```
+
+**Valid Values:**
+Object with event names mapping to arrays of hook definitions.
+
+**Source:** Claude Code 2.1.0 changelog - hooks support for commands
+
+---
+
+## Skill Schema Constraints (v2.1.0+)
+
+### Rule 117b: Skill Context Field
+
+**Severity:** info
+**Component:** skill
+**Category:** schema
+
+**Description:**
+Skills can run in a forked sub-agent context using `context: fork`.
+
+**Constraint:**
+```
+context?: "fork"
+```
+
+**Valid Values:**
+- `fork` - Run skill in forked sub-agent context
+- Omitted - Run in main context (default)
+
+**Source:** Claude Code 2.1.0 changelog - context: fork for skills
+
+---
+
+### Rule 117c: Skill Agent Field
+
+**Severity:** info
+**Component:** skill
+**Category:** schema
+
+**Description:**
+Skills can specify an agent type for execution.
+
+**Constraint:**
+```
+agent?: string
+```
+
+**Valid Values:**
+Any valid agent type name (e.g., "refactor-specialist", "go-specialist").
+
+**Source:** Claude Code 2.1.0 changelog - agent field for skills
+
+---
+
+### Rule 117d: Skill User-Invocable Field
+
+**Severity:** info
+**Component:** skill
+**Category:** schema
+
+**Description:**
+Skills in `/skills/` directories are visible in the slash command menu by default. Use `user-invocable: false` to opt out.
+
+**Constraint:**
+```
+"user-invocable"?: bool
+```
+
+**Valid Values:**
+- `true` or omitted - Skill appears in slash command menu (default for /skills/ dirs)
+- `false` - Skill hidden from slash command menu
+
+**Source:** Claude Code 2.1.0 changelog - user-invocable field for skills
+
+---
+
+### Rule 117e: Skill Hooks Field
+
+**Severity:** info
+**Component:** skill
+**Category:** schema
+
+**Description:**
+Skills can define lifecycle hooks scoped to the skill's execution.
+
+**Constraint:**
+```
+hooks?: {
+	[string]: [...#SkillHook]
+}
+```
+
+**Valid Values:**
+Object with event names (PreToolUse, PostToolUse, Stop) mapping to hook arrays.
+
+**Source:** Claude Code 2.1.0 changelog - hooks support for skills
+
+---
+
 ## Settings Schema Constraints (Rules 118-121)
 
 ### Rule 118: Hook Event Structure
@@ -369,20 +482,24 @@ Any string pattern that matches hook trigger conditions (glob patterns, regex, e
 **Category:** schema
 
 **Description:**
-Hook commands must specify type as "command". This is currently the only supported hook type.
+Hook commands must specify one of the valid hook types. As of Claude Code 2.1.0, three types are supported.
 
 **Constraint:**
 ```
+#HookType: "command" | "prompt" | "agent"
+
 #HookCommand: {
-	type: "command"
+	type: #HookType
 	...
 }
 ```
 
 **Valid Values:**
-- `command` (only valid value)
+- `command` - Execute a shell command
+- `prompt` - Modify Claude's prompt (plugins, v2.1.0+)
+- `agent` - Invoke an agent (plugins, v2.1.0+)
 
-**Source:** [Anthropic Docs - Hooks](https://code.claude.com/docs/en/hooks) - hook type values (command, prompt)
+**Source:** [Anthropic Docs - Hooks](https://code.claude.com/docs/en/hooks) - hook type values
 
 ---
 
@@ -411,6 +528,76 @@ Any non-empty string representing a shell command.
 
 ---
 
+### Rule 121a: Hook Once Field (v2.1.0+)
+
+**Severity:** error
+**Component:** settings
+**Category:** schema
+
+**Description:**
+Hook commands can specify `once: true` to run only once per session.
+
+**Constraint:**
+```
+#HookCommand: {
+	type:     #HookType
+	command:  string
+	timeout?: int
+	once?:    bool
+}
+```
+
+**Valid Values:**
+- `true` - Run hook only once per session
+- `false` or omitted - Run hook every time it triggers
+
+**Source:** Claude Code 2.1.0 changelog - once field for hooks
+
+---
+
+### Rule 121b: Settings Language Field (v2.1.0+)
+
+**Severity:** info
+**Component:** settings
+**Category:** schema
+
+**Description:**
+Configure Claude's response language.
+
+**Constraint:**
+```
+language?: string
+```
+
+**Valid Values:**
+Any language name string (e.g., "japanese", "spanish", "french").
+
+**Source:** Claude Code 2.1.0 changelog - language setting
+
+---
+
+### Rule 121c: Settings respectGitignore Field (v2.1.0+)
+
+**Severity:** info
+**Component:** settings
+**Category:** schema
+
+**Description:**
+Per-project control over @-mention file picker behavior.
+
+**Constraint:**
+```
+respectGitignore?: bool
+```
+
+**Valid Values:**
+- `true` - Hide gitignored files from @-mention picker
+- `false` - Show all files in @-mention picker
+
+**Source:** Claude Code 2.1.0 changelog - respectGitignore setting
+
+---
+
 ## CLAUDE.md Schema Constraints (Rules 122-124)
 
 ### Rule 122: Section Structure

docs/rules/settings.md

@@ -205,15 +205,15 @@ The `type` field contains a JSON string value.
 **Category:** structural
 
 **Description:**
-Hook type must be either "command" (executes a shell command) or "prompt" (modifies Claude's prompt). No other values are valid.
+Hook type must be one of the valid types. As of Claude Code 2.1.0, plugins can use "prompt" and "agent" types in addition to "command".
 
 **Pass Criteria:**
-The `type` field value is exactly "command" or "prompt".
+The `type` field value is exactly "command", "prompt", or "agent".
 
 **Fail Message:**
-`Event '[eventName]' hook [index] inner hook [innerIndex]: invalid type '[hookType]'. Valid types: command, prompt`
+`Event '[eventName]' hook [index] inner hook [innerIndex]: invalid type '[hookType]'. Valid types: command, prompt, agent`
 
-**Source:** [Anthropic Docs - Hooks](https://code.claude.com/docs/en/hooks) - "Hook type must be either 'command' (executes a shell command) or 'prompt' (modifies Claude's prompt)"
+**Source:** [Anthropic Docs - Hooks](https://code.claude.com/docs/en/hooks) - Hook type values (command, prompt, agent)
 
 ---
 
@@ -523,6 +523,54 @@ Command does not redirect to `/dev/` paths, or redirection is verified to be int
 
 ---
 
+## New Settings Fields (v2.1.0+)
+
+Claude Code 2.1.0 introduced new settings.json fields:
+
+| Field | Type | Description |
+|-------|------|-------------|
+| `language` | string | Configure Claude's response language (e.g., "japanese") |
+| `respectGitignore` | bool | Control @-mention file picker behavior |
+
+### New Hook Fields
+
+| Field | Type | Description |
+|-------|------|-------------|
+| `once` | bool | Run hook only once per session |
+
+### New Hook Types (Plugins)
+
+| Type | Description |
+|------|-------------|
+| `command` | Execute a shell command (original) |
+| `prompt` | Modify Claude's prompt (plugins, v2.1.0+) |
+| `agent` | Invoke an agent (plugins, v2.1.0+) |
+
+### Example settings.json
+
+```json
+{
+  "language": "japanese",
+  "respectGitignore": true,
+  "hooks": {
+    "SessionStart": [
+      {
+        "matcher": "",
+        "hooks": [
+          {
+            "type": "command",
+            "command": "echo 'Session started'",
+            "once": true
+          }
+        ]
+      }
+    ]
+  }
+}
+```
+
+---
+
 ## Summary
 
 Settings linting enforces:

docs/rules/skills.md

@@ -289,6 +289,38 @@ Document contains at least one of:
 
 ---
 
+## New Frontmatter Fields (v2.1.0+)
+
+Claude Code 2.1.0 introduced several new optional frontmatter fields for skills:
+
+| Field | Type | Description |
+|-------|------|-------------|
+| `context` | `"fork"` | Run skill in forked sub-agent context |
+| `agent` | string | Agent type for execution (e.g., "refactor-specialist") |
+| `user-invocable` | bool | Show in slash command menu (default: true for /skills/) |
+| `hooks` | object | Lifecycle hooks scoped to skill execution |
+
+### Example with New Fields
+
+```yaml
+---
+name: my-skill
+description: Example skill with v2.1.0 fields
+context: fork
+agent: refactor-specialist
+user-invocable: true
+hooks:
+  PreToolUse:
+    - matcher: "Bash"
+      hooks:
+        - type: command
+          command: echo "Before bash"
+          once: true
+---
+```
+
+---
+
 ## Best Practices
 
 ### Skill Structure