Permissions Guide

ClaudeCode provides several options to control what actions Claude can perform during a session.

Permission Modes

The permission_mode option controls how Claude handles permission requests:

{:ok, session} = ClaudeCode.start_link(
  permission_mode: :accept_edits
)

Tool Restrictions

Control which tools Claude can use with allowed_tools and disallowed_tools:

# Allow only specific tools
{:ok, session} = ClaudeCode.start_link(
  allowed_tools: ["View", "Edit"]
)

# Allow tools with patterns
{:ok, session} = ClaudeCode.start_link(
  allowed_tools: ["View", "Bash(git:*)"]  # Only git commands in Bash
)

# Disallow specific tools
{:ok, session} = ClaudeCode.start_link(
  disallowed_tools: ["Bash", "Edit"]
)

Common Tool Names

• View - Read files
• Edit - Modify files
• Write - Create new files
• Bash - Execute shell commands
• Glob - Search for files
• Grep - Search file contents

Tool Patterns

Use patterns to allow subsets of tool functionality:

# Only allow git commands
allowed_tools: ["Bash(git:*)"]

# Only allow npm and git
allowed_tools: ["Bash(git:*)", "Bash(npm:*)"]

Directory Access

Restrict which directories Claude can access:

{:ok, session} = ClaudeCode.start_link(
  add_dir: ["/path/to/allowed/directory"]
)

Security Considerations

1. Production environments: Use permission_mode: :accept_edits or stricter
2. Untrusted input: Always restrict tools when processing user-provided prompts
3. File access: Use add_dir to limit directory access
4. Shell commands: Use allowed_tools: ["Bash(git:*)"] patterns to restrict commands

Example: Restricted Code Review

# Safe configuration for automated code review
{:ok, session} = ClaudeCode.start_link(
  permission_mode: :default,
  allowed_tools: ["View", "Glob", "Grep"],  # Read-only tools
  add_dir: ["/app/src"]  # Only access source directory
)

review =
  session
  |> ClaudeCode.stream("Review the code for security issues")
  |> ClaudeCode.Stream.text_content()
  |> Enum.join()

Next Steps

• Configuration Guide - All configuration options
• Tool Callbacks - Monitor tool usage