FR: Add `decision: ask` support for PreToolUse hooks

[pahud]

Feature Request: Add decision: ask support for PreToolUse hooks

Summary

Add support for a decision: ask response in PreToolUse hooks that prompts the user for confirmation before executing a tool, similar to Claude Code's hook system.

Motivation

Currently, PreToolUse hooks only support two outcomes:

• Exit 0: Allow tool execution
• Exit 2: Block tool execution (returns STDERR to LLM)

There's no way for a hook to trigger an interactive user confirmation prompt. This limits the ability to implement "soft" security policies where certain commands (e.g., sudo) should require explicit user approval rather than being outright blocked.

Proposed Solution

Allow hooks to output a JSON response to STDOUT with decision: ask:

{
 "decision": "ask",
 "message": "⚠️  This command uses sudo:\n\n  sudo apt update\n\nAllow execution?"
}

When the CLI receives this response:

1. Display the message to the user
2. Prompt for confirmation (y/n)
3. If approved, proceed with tool execution
4. If denied, return denial to the LLM

Proposed Hook Output Behavior

Exit Code	STDOUT	Behavior
0	Empty	Allow
0	{"decision": "ask", "message": "..."}	Prompt user
2	-	Block (STDERR to LLM)
Other	-	Warning, allow

Use Case Example

A security hook that prompts for sudo commands instead of blocking them:

#!/usr/bin/env python3
import json, sys, re

input_data = json.load(sys.stdin)
command = input_data.get("tool_input", {}).get("command", "")

if re.search(r'(^|;|&&|\|\||\|)\s*sudo(\s|$)', command):
   print(json.dumps({
       "decision": "ask",
       "message": f"⚠️  This command uses sudo:\n\n  {command}\n\nAllow execution?"
   }))
sys.exit(0)

Prior Art

• Claude Code hooks support decision: ask for interactive approval flows

Additional Context

This feature would enable more flexible security policies where users can make case-by-case decisions rather than having blanket allow/deny rules.