Claude Code Permissions Hook

Command Permissions Hook for Claude Code

A PreToolUse hook for Claude Code that provides granular control over which tools Claude can use, with support for allow/deny rules, pattern matching, and security exclusions.

NOTE: This is a workaround for current (December 2025) limitations in Claude Code permissions - [setting Bash permissions](https://docs.claude.com/en/docs/claude-code/iam#tool-specific-permission-rules) doesn't work consistently. Built following Anthropic's [hook guidelines](https://docs.claude.com/en/docs/claude-code/iam#additional-permission-control-with-hooks).

This may be short-lived as Anthropic improves permissions. Use it if it helps, but you'll need basic Rust knowledge.

Features

• All configuration is via a single .toml file - see example.toml for an example
• Allow/deny rules with regex pattern matching for tool inputs
• Exclude patterns for handling edge cases (e.g., block .. in allowed paths)
• Audit logging of tool use decisions to JSON file

Documentation

• Configuration Guide - How to write rules for each supported tool
• Tool Input Schemas - Reference for Claude Code tool input formats

Installation

Requires Rust. Install via [rustup](https://rustup.rs/) if you want to use this project. Rust is fun!

cargo build --release

Binary: `target/release/claude-code-permissions-hook`

Configuration

Create a TOML configuration file (see `example.toml`):

[audit]
audit_file = "/tmp/claude-tool-use.json"
# Audit level: off, matched (default), all
# - off: no auditing
# - matched: audit only tool use that hits a rule (allow/deny)
# - all: audit everything including passthrough
audit_level = "matched"

# Allow rules - checked after deny rules
[[allow]]
tool = "Read"
file_path_regex = "^/Users/korny/Dropbox/prj/.*"
file_path_exclude_regex = "\\.\\."  # Block path traversal

[[allow]]
tool = "Bash"
command_regex = "^c