Add ai-code-project-template repo files.
This commit is contained in:
743
ai_context/claude_code/CLAUDE_CODE_HOOKS.md
Normal file
743
ai_context/claude_code/CLAUDE_CODE_HOOKS.md
Normal file
@@ -0,0 +1,743 @@
|
||||
# Hooks reference
|
||||
|
||||
> This page provides reference documentation for implementing hooks in Claude Code.
|
||||
|
||||
<Tip>
|
||||
For a quickstart guide with examples, see [Get started with Claude Code hooks](/en/docs/claude-code/hooks-guide).
|
||||
</Tip>
|
||||
|
||||
## Configuration
|
||||
|
||||
Claude Code hooks are configured in your [settings files](/en/docs/claude-code/settings):
|
||||
|
||||
- `~/.claude/settings.json` - User settings
|
||||
- `.claude/settings.json` - Project settings
|
||||
- `.claude/settings.local.json` - Local project settings (not committed)
|
||||
- Enterprise managed policy settings
|
||||
|
||||
### Structure
|
||||
|
||||
Hooks are organized by matchers, where each matcher can have multiple hooks:
|
||||
|
||||
```json
|
||||
{
|
||||
"hooks": {
|
||||
"EventName": [
|
||||
{
|
||||
"matcher": "ToolPattern",
|
||||
"hooks": [
|
||||
{
|
||||
"type": "command",
|
||||
"command": "your-command-here"
|
||||
}
|
||||
]
|
||||
}
|
||||
]
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
- **matcher**: Pattern to match tool names, case-sensitive (only applicable for
|
||||
`PreToolUse` and `PostToolUse`)
|
||||
- Simple strings match exactly: `Write` matches only the Write tool
|
||||
- Supports regex: `Edit|Write` or `Notebook.*`
|
||||
- Use `*` to match all tools. You can also use empty string (`""`) or leave
|
||||
`matcher` blank.
|
||||
- **hooks**: Array of commands to execute when the pattern matches
|
||||
- `type`: Currently only `"command"` is supported
|
||||
- `command`: The bash command to execute (can use `$CLAUDE_PROJECT_DIR`
|
||||
environment variable)
|
||||
- `timeout`: (Optional) How long a command should run, in seconds, before
|
||||
canceling that specific command.
|
||||
|
||||
For events like `UserPromptSubmit`, `Notification`, `Stop`, and `SubagentStop`
|
||||
that don't use matchers, you can omit the matcher field:
|
||||
|
||||
```json
|
||||
{
|
||||
"hooks": {
|
||||
"UserPromptSubmit": [
|
||||
{
|
||||
"hooks": [
|
||||
{
|
||||
"type": "command",
|
||||
"command": "/path/to/prompt-validator.py"
|
||||
}
|
||||
]
|
||||
}
|
||||
]
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
### Project-Specific Hook Scripts
|
||||
|
||||
You can use the environment variable `CLAUDE_PROJECT_DIR` (only available when
|
||||
Claude Code spawns the hook command) to reference scripts stored in your project,
|
||||
ensuring they work regardless of Claude's current directory:
|
||||
|
||||
```json
|
||||
{
|
||||
"hooks": {
|
||||
"PostToolUse": [
|
||||
{
|
||||
"matcher": "Write|Edit",
|
||||
"hooks": [
|
||||
{
|
||||
"type": "command",
|
||||
"command": "$CLAUDE_PROJECT_DIR/.claude/hooks/check-style.sh"
|
||||
}
|
||||
]
|
||||
}
|
||||
]
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
## Hook Events
|
||||
|
||||
### PreToolUse
|
||||
|
||||
Runs after Claude creates tool parameters and before processing the tool call.
|
||||
|
||||
**Common matchers:**
|
||||
|
||||
- `Task` - Subagent tasks (see [subagents documentation](/en/docs/claude-code/sub-agents))
|
||||
- `Bash` - Shell commands
|
||||
- `Glob` - File pattern matching
|
||||
- `Grep` - Content search
|
||||
- `Read` - File reading
|
||||
- `Edit`, `MultiEdit` - File editing
|
||||
- `Write` - File writing
|
||||
- `WebFetch`, `WebSearch` - Web operations
|
||||
|
||||
### PostToolUse
|
||||
|
||||
Runs immediately after a tool completes successfully.
|
||||
|
||||
Recognizes the same matcher values as PreToolUse.
|
||||
|
||||
### Notification
|
||||
|
||||
Runs when Claude Code sends notifications. Notifications are sent when:
|
||||
|
||||
1. Claude needs your permission to use a tool. Example: "Claude needs your
|
||||
permission to use Bash"
|
||||
2. The prompt input has been idle for at least 60 seconds. "Claude is waiting
|
||||
for your input"
|
||||
|
||||
### UserPromptSubmit
|
||||
|
||||
Runs when the user submits a prompt, before Claude processes it. This allows you
|
||||
to add additional context based on the prompt/conversation, validate prompts, or
|
||||
block certain types of prompts.
|
||||
|
||||
### Stop
|
||||
|
||||
Runs when the main Claude Code agent has finished responding. Does not run if
|
||||
the stoppage occurred due to a user interrupt.
|
||||
|
||||
### SubagentStop
|
||||
|
||||
Runs when a Claude Code subagent (Task tool call) has finished responding.
|
||||
|
||||
### PreCompact
|
||||
|
||||
Runs before Claude Code is about to run a compact operation.
|
||||
|
||||
**Matchers:**
|
||||
|
||||
- `manual` - Invoked from `/compact`
|
||||
- `auto` - Invoked from auto-compact (due to full context window)
|
||||
|
||||
### SessionStart
|
||||
|
||||
Runs when Claude Code starts a new session or resumes an existing session (which
|
||||
currently does start a new session under the hood). Useful for loading in
|
||||
development context like existing issues or recent changes to your codebase.
|
||||
|
||||
**Matchers:**
|
||||
|
||||
- `startup` - Invoked from startup
|
||||
- `resume` - Invoked from `--resume`, `--continue`, or `/resume`
|
||||
- `clear` - Invoked from `/clear`
|
||||
|
||||
## Hook Input
|
||||
|
||||
Hooks receive JSON data via stdin containing session information and
|
||||
event-specific data:
|
||||
|
||||
```typescript
|
||||
{
|
||||
// Common fields
|
||||
session_id: string
|
||||
transcript_path: string // Path to conversation JSON
|
||||
cwd: string // The current working directory when the hook is invoked
|
||||
|
||||
// Event-specific fields
|
||||
hook_event_name: string
|
||||
...
|
||||
}
|
||||
```
|
||||
|
||||
### PreToolUse Input
|
||||
|
||||
The exact schema for `tool_input` depends on the tool.
|
||||
|
||||
```json
|
||||
{
|
||||
"session_id": "abc123",
|
||||
"transcript_path": "/Users/.../.claude/projects/.../00893aaf-19fa-41d2-8238-13269b9b3ca0.jsonl",
|
||||
"cwd": "/Users/...",
|
||||
"hook_event_name": "PreToolUse",
|
||||
"tool_name": "Write",
|
||||
"tool_input": {
|
||||
"file_path": "/path/to/file.txt",
|
||||
"content": "file content"
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
### PostToolUse Input
|
||||
|
||||
The exact schema for `tool_input` and `tool_response` depends on the tool.
|
||||
|
||||
```json
|
||||
{
|
||||
"session_id": "abc123",
|
||||
"transcript_path": "/Users/.../.claude/projects/.../00893aaf-19fa-41d2-8238-13269b9b3ca0.jsonl",
|
||||
"cwd": "/Users/...",
|
||||
"hook_event_name": "PostToolUse",
|
||||
"tool_name": "Write",
|
||||
"tool_input": {
|
||||
"file_path": "/path/to/file.txt",
|
||||
"content": "file content"
|
||||
},
|
||||
"tool_response": {
|
||||
"filePath": "/path/to/file.txt",
|
||||
"success": true
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
### Notification Input
|
||||
|
||||
```json
|
||||
{
|
||||
"session_id": "abc123",
|
||||
"transcript_path": "/Users/.../.claude/projects/.../00893aaf-19fa-41d2-8238-13269b9b3ca0.jsonl",
|
||||
"cwd": "/Users/...",
|
||||
"hook_event_name": "Notification",
|
||||
"message": "Task completed successfully"
|
||||
}
|
||||
```
|
||||
|
||||
### UserPromptSubmit Input
|
||||
|
||||
```json
|
||||
{
|
||||
"session_id": "abc123",
|
||||
"transcript_path": "/Users/.../.claude/projects/.../00893aaf-19fa-41d2-8238-13269b9b3ca0.jsonl",
|
||||
"cwd": "/Users/...",
|
||||
"hook_event_name": "UserPromptSubmit",
|
||||
"prompt": "Write a function to calculate the factorial of a number"
|
||||
}
|
||||
```
|
||||
|
||||
### Stop and SubagentStop Input
|
||||
|
||||
`stop_hook_active` is true when Claude Code is already continuing as a result of
|
||||
a stop hook. Check this value or process the transcript to prevent Claude Code
|
||||
from running indefinitely.
|
||||
|
||||
```json
|
||||
{
|
||||
"session_id": "abc123",
|
||||
"transcript_path": "~/.claude/projects/.../00893aaf-19fa-41d2-8238-13269b9b3ca0.jsonl",
|
||||
"hook_event_name": "Stop",
|
||||
"stop_hook_active": true
|
||||
}
|
||||
```
|
||||
|
||||
### PreCompact Input
|
||||
|
||||
For `manual`, `custom_instructions` comes from what the user passes into
|
||||
`/compact`. For `auto`, `custom_instructions` is empty.
|
||||
|
||||
```json
|
||||
{
|
||||
"session_id": "abc123",
|
||||
"transcript_path": "~/.claude/projects/.../00893aaf-19fa-41d2-8238-13269b9b3ca0.jsonl",
|
||||
"hook_event_name": "PreCompact",
|
||||
"trigger": "manual",
|
||||
"custom_instructions": ""
|
||||
}
|
||||
```
|
||||
|
||||
### SessionStart Input
|
||||
|
||||
```json
|
||||
{
|
||||
"session_id": "abc123",
|
||||
"transcript_path": "~/.claude/projects/.../00893aaf-19fa-41d2-8238-13269b9b3ca0.jsonl",
|
||||
"hook_event_name": "SessionStart",
|
||||
"source": "startup"
|
||||
}
|
||||
```
|
||||
|
||||
## Hook Output
|
||||
|
||||
There are two ways for hooks to return output back to Claude Code. The output
|
||||
communicates whether to block and any feedback that should be shown to Claude
|
||||
and the user.
|
||||
|
||||
### Simple: Exit Code
|
||||
|
||||
Hooks communicate status through exit codes, stdout, and stderr:
|
||||
|
||||
- **Exit code 0**: Success. `stdout` is shown to the user in transcript mode
|
||||
(CTRL-R), except for `UserPromptSubmit` and `SessionStart`, where stdout is
|
||||
added to the context.
|
||||
- **Exit code 2**: Blocking error. `stderr` is fed back to Claude to process
|
||||
automatically. See per-hook-event behavior below.
|
||||
- **Other exit codes**: Non-blocking error. `stderr` is shown to the user and
|
||||
execution continues.
|
||||
|
||||
<Warning>
|
||||
Reminder: Claude Code does not see stdout if the exit code is 0, except for
|
||||
the `UserPromptSubmit` hook where stdout is injected as context.
|
||||
</Warning>
|
||||
|
||||
#### Exit Code 2 Behavior
|
||||
|
||||
| Hook Event | Behavior |
|
||||
| ------------------ | ------------------------------------------------------------------ |
|
||||
| `PreToolUse` | Blocks the tool call, shows stderr to Claude |
|
||||
| `PostToolUse` | Shows stderr to Claude (tool already ran) |
|
||||
| `Notification` | N/A, shows stderr to user only |
|
||||
| `UserPromptSubmit` | Blocks prompt processing, erases prompt, shows stderr to user only |
|
||||
| `Stop` | Blocks stoppage, shows stderr to Claude |
|
||||
| `SubagentStop` | Blocks stoppage, shows stderr to Claude subagent |
|
||||
| `PreCompact` | N/A, shows stderr to user only |
|
||||
| `SessionStart` | N/A, shows stderr to user only |
|
||||
|
||||
### Advanced: JSON Output
|
||||
|
||||
Hooks can return structured JSON in `stdout` for more sophisticated control:
|
||||
|
||||
#### Common JSON Fields
|
||||
|
||||
All hook types can include these optional fields:
|
||||
|
||||
```json
|
||||
{
|
||||
"continue": true, // Whether Claude should continue after hook execution (default: true)
|
||||
"stopReason": "string" // Message shown when continue is false
|
||||
"suppressOutput": true, // Hide stdout from transcript mode (default: false)
|
||||
}
|
||||
```
|
||||
|
||||
If `continue` is false, Claude stops processing after the hooks run.
|
||||
|
||||
- For `PreToolUse`, this is different from `"permissionDecision": "deny"`, which
|
||||
only blocks a specific tool call and provides automatic feedback to Claude.
|
||||
- For `PostToolUse`, this is different from `"decision": "block"`, which
|
||||
provides automated feedback to Claude.
|
||||
- For `UserPromptSubmit`, this prevents the prompt from being processed.
|
||||
- For `Stop` and `SubagentStop`, this takes precedence over any
|
||||
`"decision": "block"` output.
|
||||
- In all cases, `"continue" = false` takes precedence over any
|
||||
`"decision": "block"` output.
|
||||
|
||||
`stopReason` accompanies `continue` with a reason shown to the user, not shown
|
||||
to Claude.
|
||||
|
||||
#### `PreToolUse` Decision Control
|
||||
|
||||
`PreToolUse` hooks can control whether a tool call proceeds.
|
||||
|
||||
- `"allow"` bypasses the permission system. `permissionDecisionReason` is shown
|
||||
to the user but not to Claude. (_Deprecated `"approve"` value + `reason` has
|
||||
the same behavior._)
|
||||
- `"deny"` prevents the tool call from executing. `permissionDecisionReason` is
|
||||
shown to Claude. (_`"block"` value + `reason` has the same behavior._)
|
||||
- `"ask"` asks the user to confirm the tool call in the UI.
|
||||
`permissionDecisionReason` is shown to the user but not to Claude.
|
||||
|
||||
```json
|
||||
{
|
||||
"hookSpecificOutput": {
|
||||
"hookEventName": "PreToolUse",
|
||||
"permissionDecision": "allow" | "deny" | "ask",
|
||||
"permissionDecisionReason": "My reason here (shown to user)"
|
||||
},
|
||||
"decision": "approve" | "block" | undefined, // Deprecated for PreToolUse but still supported
|
||||
"reason": "Explanation for decision" // Deprecated for PreToolUse but still supported
|
||||
}
|
||||
```
|
||||
|
||||
#### `PostToolUse` Decision Control
|
||||
|
||||
`PostToolUse` hooks can control whether a tool call proceeds.
|
||||
|
||||
- `"block"` automatically prompts Claude with `reason`.
|
||||
- `undefined` does nothing. `reason` is ignored.
|
||||
|
||||
```json
|
||||
{
|
||||
"decision": "block" | undefined,
|
||||
"reason": "Explanation for decision"
|
||||
}
|
||||
```
|
||||
|
||||
#### `UserPromptSubmit` Decision Control
|
||||
|
||||
`UserPromptSubmit` hooks can control whether a user prompt is processed.
|
||||
|
||||
- `"block"` prevents the prompt from being processed. The submitted prompt is
|
||||
erased from context. `"reason"` is shown to the user but not added to context.
|
||||
- `undefined` allows the prompt to proceed normally. `"reason"` is ignored.
|
||||
- `"hookSpecificOutput.additionalContext"` adds the string to the context if not
|
||||
blocked.
|
||||
|
||||
```json
|
||||
{
|
||||
"decision": "block" | undefined,
|
||||
"reason": "Explanation for decision",
|
||||
"hookSpecificOutput": {
|
||||
"hookEventName": "UserPromptSubmit",
|
||||
"additionalContext": "My additional context here"
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
#### `Stop`/`SubagentStop` Decision Control
|
||||
|
||||
`Stop` and `SubagentStop` hooks can control whether Claude must continue.
|
||||
|
||||
- `"block"` prevents Claude from stopping. You must populate `reason` for Claude
|
||||
to know how to proceed.
|
||||
- `undefined` allows Claude to stop. `reason` is ignored.
|
||||
|
||||
```json
|
||||
{
|
||||
"decision": "block" | undefined,
|
||||
"reason": "Must be provided when Claude is blocked from stopping"
|
||||
}
|
||||
```
|
||||
|
||||
#### `SessionStart` Decision Control
|
||||
|
||||
`SessionStart` hooks allow you to load in context at the start of a session.
|
||||
|
||||
- `"hookSpecificOutput.additionalContext"` adds the string to the context.
|
||||
|
||||
```json
|
||||
{
|
||||
"hookSpecificOutput": {
|
||||
"hookEventName": "SessionStart",
|
||||
"additionalContext": "My additional context here"
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
#### Exit Code Example: Bash Command Validation
|
||||
|
||||
```python
|
||||
#!/usr/bin/env python3
|
||||
import json
|
||||
import re
|
||||
import sys
|
||||
|
||||
# Define validation rules as a list of (regex pattern, message) tuples
|
||||
VALIDATION_RULES = [
|
||||
(
|
||||
r"\bgrep\b(?!.*\|)",
|
||||
"Use 'rg' (ripgrep) instead of 'grep' for better performance and features",
|
||||
),
|
||||
(
|
||||
r"\bfind\s+\S+\s+-name\b",
|
||||
"Use 'rg --files | rg pattern' or 'rg --files -g pattern' instead of 'find -name' for better performance",
|
||||
),
|
||||
]
|
||||
|
||||
|
||||
def validate_command(command: str) -> list[str]:
|
||||
issues = []
|
||||
for pattern, message in VALIDATION_RULES:
|
||||
if re.search(pattern, command):
|
||||
issues.append(message)
|
||||
return issues
|
||||
|
||||
|
||||
try:
|
||||
input_data = json.load(sys.stdin)
|
||||
except json.JSONDecodeError as e:
|
||||
print(f"Error: Invalid JSON input: {e}", file=sys.stderr)
|
||||
sys.exit(1)
|
||||
|
||||
tool_name = input_data.get("tool_name", "")
|
||||
tool_input = input_data.get("tool_input", {})
|
||||
command = tool_input.get("command", "")
|
||||
|
||||
if tool_name != "Bash" or not command:
|
||||
sys.exit(1)
|
||||
|
||||
# Validate the command
|
||||
issues = validate_command(command)
|
||||
|
||||
if issues:
|
||||
for message in issues:
|
||||
print(f"• {message}", file=sys.stderr)
|
||||
# Exit code 2 blocks tool call and shows stderr to Claude
|
||||
sys.exit(2)
|
||||
```
|
||||
|
||||
#### JSON Output Example: UserPromptSubmit to Add Context and Validation
|
||||
|
||||
<Note>
|
||||
For `UserPromptSubmit` hooks, you can inject context using either method:
|
||||
|
||||
- Exit code 0 with stdout: Claude sees the context (special case for `UserPromptSubmit`)
|
||||
- JSON output: Provides more control over the behavior
|
||||
</Note>
|
||||
|
||||
```python
|
||||
#!/usr/bin/env python3
|
||||
import json
|
||||
import sys
|
||||
import re
|
||||
import datetime
|
||||
|
||||
# Load input from stdin
|
||||
try:
|
||||
input_data = json.load(sys.stdin)
|
||||
except json.JSONDecodeError as e:
|
||||
print(f"Error: Invalid JSON input: {e}", file=sys.stderr)
|
||||
sys.exit(1)
|
||||
|
||||
prompt = input_data.get("prompt", "")
|
||||
|
||||
# Check for sensitive patterns
|
||||
sensitive_patterns = [
|
||||
(r"(?i)\b(password|secret|key|token)\s*[:=]", "Prompt contains potential secrets"),
|
||||
]
|
||||
|
||||
for pattern, message in sensitive_patterns:
|
||||
if re.search(pattern, prompt):
|
||||
# Use JSON output to block with a specific reason
|
||||
output = {
|
||||
"decision": "block",
|
||||
"reason": f"Security policy violation: {message}. Please rephrase your request without sensitive information."
|
||||
}
|
||||
print(json.dumps(output))
|
||||
sys.exit(0)
|
||||
|
||||
# Add current time to context
|
||||
context = f"Current time: {datetime.datetime.now()}"
|
||||
print(context)
|
||||
|
||||
"""
|
||||
The following is also equivalent:
|
||||
print(json.dumps({
|
||||
"hookSpecificOutput": {
|
||||
"hookEventName": "UserPromptSubmit",
|
||||
"additionalContext": context,
|
||||
},
|
||||
}))
|
||||
"""
|
||||
|
||||
# Allow the prompt to proceed with the additional context
|
||||
sys.exit(0)
|
||||
```
|
||||
|
||||
#### JSON Output Example: PreToolUse with Approval
|
||||
|
||||
```python
|
||||
#!/usr/bin/env python3
|
||||
import json
|
||||
import sys
|
||||
|
||||
# Load input from stdin
|
||||
try:
|
||||
input_data = json.load(sys.stdin)
|
||||
except json.JSONDecodeError as e:
|
||||
print(f"Error: Invalid JSON input: {e}", file=sys.stderr)
|
||||
sys.exit(1)
|
||||
|
||||
tool_name = input_data.get("tool_name", "")
|
||||
tool_input = input_data.get("tool_input", {})
|
||||
|
||||
# Example: Auto-approve file reads for documentation files
|
||||
if tool_name == "Read":
|
||||
file_path = tool_input.get("file_path", "")
|
||||
if file_path.endswith((".md", ".mdx", ".txt", ".json")):
|
||||
# Use JSON output to auto-approve the tool call
|
||||
output = {
|
||||
"decision": "approve",
|
||||
"reason": "Documentation file auto-approved",
|
||||
"suppressOutput": True # Don't show in transcript mode
|
||||
}
|
||||
print(json.dumps(output))
|
||||
sys.exit(0)
|
||||
|
||||
# For other cases, let the normal permission flow proceed
|
||||
sys.exit(0)
|
||||
```
|
||||
|
||||
## Working with MCP Tools
|
||||
|
||||
Claude Code hooks work seamlessly with
|
||||
[Model Context Protocol (MCP) tools](/en/docs/claude-code/mcp). When MCP servers
|
||||
provide tools, they appear with a special naming pattern that you can match in
|
||||
your hooks.
|
||||
|
||||
### MCP Tool Naming
|
||||
|
||||
MCP tools follow the pattern `mcp__<server>__<tool>`, for example:
|
||||
|
||||
- `mcp__memory__create_entities` - Memory server's create entities tool
|
||||
- `mcp__filesystem__read_file` - Filesystem server's read file tool
|
||||
- `mcp__github__search_repositories` - GitHub server's search tool
|
||||
|
||||
### Configuring Hooks for MCP Tools
|
||||
|
||||
You can target specific MCP tools or entire MCP servers:
|
||||
|
||||
```json
|
||||
{
|
||||
"hooks": {
|
||||
"PreToolUse": [
|
||||
{
|
||||
"matcher": "mcp__memory__.*",
|
||||
"hooks": [
|
||||
{
|
||||
"type": "command",
|
||||
"command": "echo 'Memory operation initiated' >> ~/mcp-operations.log"
|
||||
}
|
||||
]
|
||||
},
|
||||
{
|
||||
"matcher": "mcp__.*__write.*",
|
||||
"hooks": [
|
||||
{
|
||||
"type": "command",
|
||||
"command": "/home/user/scripts/validate-mcp-write.py"
|
||||
}
|
||||
]
|
||||
}
|
||||
]
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
## Examples
|
||||
|
||||
<Tip>
|
||||
For practical examples including code formatting, notifications, and file protection, see [More Examples](/en/docs/claude-code/hooks-guide#more-examples) in the get started guide.
|
||||
</Tip>
|
||||
|
||||
## Security Considerations
|
||||
|
||||
### Disclaimer
|
||||
|
||||
**USE AT YOUR OWN RISK**: Claude Code hooks execute arbitrary shell commands on
|
||||
your system automatically. By using hooks, you acknowledge that:
|
||||
|
||||
- You are solely responsible for the commands you configure
|
||||
- Hooks can modify, delete, or access any files your user account can access
|
||||
- Malicious or poorly written hooks can cause data loss or system damage
|
||||
- Anthropic provides no warranty and assumes no liability for any damages
|
||||
resulting from hook usage
|
||||
- You should thoroughly test hooks in a safe environment before production use
|
||||
|
||||
Always review and understand any hook commands before adding them to your
|
||||
configuration.
|
||||
|
||||
### Security Best Practices
|
||||
|
||||
Here are some key practices for writing more secure hooks:
|
||||
|
||||
1. **Validate and sanitize inputs** - Never trust input data blindly
|
||||
2. **Always quote shell variables** - Use `"$VAR"` not `$VAR`
|
||||
3. **Block path traversal** - Check for `..` in file paths
|
||||
4. **Use absolute paths** - Specify full paths for scripts (use
|
||||
`$CLAUDE_PROJECT_DIR` for the project path)
|
||||
5. **Skip sensitive files** - Avoid `.env`, `.git/`, keys, etc.
|
||||
|
||||
### Configuration Safety
|
||||
|
||||
Direct edits to hooks in settings files don't take effect immediately. Claude
|
||||
Code:
|
||||
|
||||
1. Captures a snapshot of hooks at startup
|
||||
2. Uses this snapshot throughout the session
|
||||
3. Warns if hooks are modified externally
|
||||
4. Requires review in `/hooks` menu for changes to apply
|
||||
|
||||
This prevents malicious hook modifications from affecting your current session.
|
||||
|
||||
## Hook Execution Details
|
||||
|
||||
- **Timeout**: 60-second execution limit by default, configurable per command.
|
||||
- A timeout for an individual command does not affect the other commands.
|
||||
- **Parallelization**: All matching hooks run in parallel
|
||||
- **Environment**: Runs in current directory with Claude Code's environment
|
||||
- The `CLAUDE_PROJECT_DIR` environment variable is available and contains the
|
||||
absolute path to the project root directory
|
||||
- **Input**: JSON via stdin
|
||||
- **Output**:
|
||||
- PreToolUse/PostToolUse/Stop: Progress shown in transcript (Ctrl-R)
|
||||
- Notification: Logged to debug only (`--debug`)
|
||||
|
||||
## Debugging
|
||||
|
||||
### Basic Troubleshooting
|
||||
|
||||
If your hooks aren't working:
|
||||
|
||||
1. **Check configuration** - Run `/hooks` to see if your hook is registered
|
||||
2. **Verify syntax** - Ensure your JSON settings are valid
|
||||
3. **Test commands** - Run hook commands manually first
|
||||
4. **Check permissions** - Make sure scripts are executable
|
||||
5. **Review logs** - Use `claude --debug` to see hook execution details
|
||||
|
||||
Common issues:
|
||||
|
||||
- **Quotes not escaped** - Use `\"` inside JSON strings
|
||||
- **Wrong matcher** - Check tool names match exactly (case-sensitive)
|
||||
- **Command not found** - Use full paths for scripts
|
||||
|
||||
### Advanced Debugging
|
||||
|
||||
For complex hook issues:
|
||||
|
||||
1. **Inspect hook execution** - Use `claude --debug` to see detailed hook
|
||||
execution
|
||||
2. **Validate JSON schemas** - Test hook input/output with external tools
|
||||
3. **Check environment variables** - Verify Claude Code's environment is correct
|
||||
4. **Test edge cases** - Try hooks with unusual file paths or inputs
|
||||
5. **Monitor system resources** - Check for resource exhaustion during hook
|
||||
execution
|
||||
6. **Use structured logging** - Implement logging in your hook scripts
|
||||
|
||||
### Debug Output Example
|
||||
|
||||
Use `claude --debug` to see hook execution details:
|
||||
|
||||
```
|
||||
[DEBUG] Executing hooks for PostToolUse:Write
|
||||
[DEBUG] Getting matching hook commands for PostToolUse with query: Write
|
||||
[DEBUG] Found 1 hook matchers in settings
|
||||
[DEBUG] Matched 1 hooks for query "Write"
|
||||
[DEBUG] Found 1 hook commands to execute
|
||||
[DEBUG] Executing hook command: <Your command> with timeout 60000ms
|
||||
[DEBUG] Hook command completed with status 0: <Your stdout>
|
||||
```
|
||||
|
||||
Progress messages appear in transcript mode (Ctrl-R) showing:
|
||||
|
||||
- Which hook is running
|
||||
- Command being executed
|
||||
- Success/failure status
|
||||
- Output or error messages
|
Reference in New Issue
Block a user