How to Use Plan Mode Effectively in Claude Code

Plan Mode is a powerful feature in Claude Code that separates the thinking phase from the doing phase. Instead of diving straight into code changes, Plan Mode lets you and Claude align on an implementation strategy first, preventing wasted effort on complex tasks.

Understanding Plan Mode

When Claude enters Plan Mode, it operates in a read-only state. It can explore your codebase, search for patterns, read files, and analyze architecture, but it cannot make any edits. This constraint is intentional: it forces thorough exploration and planning before any changes occur.

Key characteristics of Plan Mode:

• Read-only access - Claude can use Read, Grep, Glob, and search tools but cannot use Edit or Write
• Exploration-focused - Encourages comprehensive codebase analysis before changes
• Collaborative planning - You can discuss and refine the approach iteratively
• Explicit approval - Implementation only begins after you approve the plan

Think of Plan Mode as architectural design before construction. You wouldn't start building a house without blueprints, and you shouldn't start complex refactoring without a clear plan.

When to Use Plan Mode

Plan Mode adds value when the task requires exploration, has multiple valid approaches, or involves changes across many files.

Good candidates for Plan Mode

• New features - When you need to understand where code should live and how it integrates
• Multi-file refactoring - Renaming, restructuring, or moving functionality across files
• Architectural changes - Modifying patterns that affect multiple parts of the codebase
• Unfamiliar codebases - When Claude (or you) needs to understand existing patterns first
• Complex bug fixes - Issues that span multiple components or have unclear root causes
• Performance optimization - When you need to identify bottlenecks before implementing fixes

Skip Plan Mode for

• Single-line fixes - Quick corrections that don't need exploration
• Specific instructions - When you know exactly what change you want
• Repetitive tasks - When the pattern is already established
• Documentation updates - Simple content changes without architectural implications
• Adding tests - When the implementation already exists and you just need coverage

Entering Plan Mode

There are two ways to enter Plan Mode:

Using the /plan command

The most direct method is the /plan command:

You: /plan Add user authentication to the application

Claude will enter Plan Mode and begin exploring your codebase to understand the current authentication setup, identify where new code should live, and outline an implementation approach.

Claude suggesting Plan Mode

For complex requests, Claude may suggest entering Plan Mode proactively:

You: Refactor the data layer to use a repository pattern

Claude: This is a significant architectural change that will affect many files.
I recommend entering Plan Mode to explore the current structure and design
the new pattern before making changes. Should I enter Plan Mode?

You can accept or decline this suggestion based on your preference.

What Claude Can Do in Plan Mode

While in Plan Mode, Claude has access to all read and exploration tools:

This means Claude can thoroughly investigate your codebase, understand patterns, check dependencies, and build a comprehensive mental model before proposing changes.

Reviewing and Refining Plans

Plan Mode is collaborative. After Claude presents an initial plan, you can:

Ask clarifying questions:

You: Why did you choose to put the auth middleware in /lib instead of /middleware?

Request changes to the approach:

You: I'd prefer to use JWT tokens instead of session-based auth. Can you revise the plan?

Suggest alternatives:

You: What if we used the existing user service instead of creating a new one?

Request more exploration:

You: Can you check how authentication is handled in the mobile API first?

Claude will revise the plan based on your feedback while remaining in Plan Mode. Only approve when you're satisfied with the direction.

Approving Plans and Exiting

When you're happy with the plan, you can approve it:

You: This plan looks good. Let's proceed with implementation.

Claude will exit Plan Mode using the ExitPlanMode tool and begin implementing the approved plan. At this point, Claude regains access to Edit and Write tools.

Important: Approval is explicit. Claude won't exit Plan Mode and start editing until you confirm you want to proceed.

Plan Mode with Task Lists

Plan Mode integrates naturally with Claude's task tracking capabilities. For complex plans, Claude can create a structured task list:

You: /plan Migrate the database from MySQL to PostgreSQL

Claude: [Explores codebase, then creates task list]

Task List:
1. Audit current MySQL queries for PostgreSQL compatibility
2. Update connection configuration
3. Modify ORM models for PostgreSQL-specific features
4. Update migration scripts
5. Adjust date/time handling for PostgreSQL
6. Test all database operations

This task list persists after exiting Plan Mode, helping track progress through the implementation. Claude can mark tasks as in_progress and completed as work proceeds.

Best Practices for Effective Planning

Be specific about constraints

When entering Plan Mode, share relevant constraints upfront:

You: /plan Add caching to the API, but we can't add Redis - must use in-memory caching only

Let Claude explore before directing

Resist the urge to dictate the solution immediately. Let Claude investigate first:

# Less effective
You: /plan Add authentication using passport.js with local strategy in /auth folder

# More effective
You: /plan Add user authentication. What approaches would work with our current stack?

Use Plan Mode for learning

Plan Mode is excellent for understanding unfamiliar codebases:

You: /plan I'm new to this project. Help me understand how the payment processing works before we add refund functionality.

Keep plans focused

For very large changes, consider breaking them into multiple planning sessions:

# Instead of one massive plan
You: /plan Rewrite the entire frontend in a new framework

# Break into phases
You: /plan Phase 1: Identify all components that need migration and their dependencies

Document the plan

After approving a complex plan, consider asking Claude to add key decisions to your project documentation or CLAUDE.md for future reference.

Common Pitfalls to Avoid

• Approving too quickly - Take time to understand and refine the plan
• Over-planning simple tasks - Don't use Plan Mode for trivial changes
• Forgetting to exit - If stuck in Plan Mode, explicitly tell Claude to proceed
• Not providing context - Share relevant constraints and preferences upfront

Next Steps

• Configure CLAUDE.md to set project-specific planning guidelines
• Install Claude Code CLI if you haven't already
• Read about working with large codebases where Plan Mode is especially valuable

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