# Useful but Little-Known Features of Claude Agent SDK 🌍 Want Claude to plan changes without touching your code? Plan mode restricts the agent to read-only exploration! Claude Agent SDK's plan mode lets Claude analyze your codebase and propose changes using only read-only tools, never editing source files. 📌 Title: Plan Mode (Read-Only Execution Only) 🔗 URL: 🧩 Overview Setting `permission_mode="plan"` restricts Claude to read-only tools such as Read, Grep, Glob, and read-only shell commands. Edit, Write, and write-mode Bash operations are blocked. Claude may use `AskUserQuestion` to clarify requirements before finalizing the plan. This mode is ideal for code review, architecture analysis, and change proposals where you want insights without side effects. 🛠 How to Use ```python # Python - plan mode for code review import asyncio from claude_agent_sdk import query, ClaudeAgentOptions async def main(): async for message in query( prompt="Analyze security issues in the auth module and propose a fix plan", options=ClaudeAgentOptions( permission_mode="plan", # Read-only analysis ), ): if hasattr(message, "result"): print(message.result) ``` ```typescript // TypeScript for await (const message of query({ prompt: "Analyze security issues in the auth module and propose a fix plan", options: { permissionMode: "plan" // Read-only analysis } })) { if ("result" in message) console.log(message.result); } ``` 🏗 Integration into Production Systems - Use for automated PR reviews that surface issues and suggestions without modifying code - Safely explore and understand new codebases during onboarding or investigation phases - Implement a "plan then execute" workflow: review the plan, then switch to `acceptEdits` mode - Combine with `set_permission_mode()` to transition from planning to execution after human approval 💡 Use Cases 📋 Generate change proposals in code reviews, leaving actual modifications to human judgment 🔍 Safely analyze architecture of large codebases without risk of accidental changes 📝 Build refactoring plans for team consensus before execution ⚠️ Caveats - Read-only shell commands may still execute - `AskUserQuestion` may be triggered, so for fully unattended operation, dontAsk mode is more appropriate - To act on the plan, you need a new session or a dynamic permission mode change ✨ "Plan first, execute second" is a fundamental engineering practice. Use plan mode to safely analyze, then commit to changes only after you're confident in the approach! #ClaudeAgentSDK# #AIAgent#