Claude Code Plan Mode: Think Before You Code (2026 Guide)

The best engineers don't start coding immediately. They analyze, design, and plan. Then they execute.

Claude Code's Plan Mode brings this discipline to AI-assisted development. It's like putting Claude in "architect mode" where it can only observe, analyze, and plan—but never execute.

//What is Plan Mode?

Plan Mode is a read-only operating mode in Claude Code. When active, Claude can:

• Read and analyze your codebase
• Search for patterns and dependencies
• Create comprehensive implementation plans
• Ask clarifying questions
• Write plans to markdown files

What it cannot do:

• Create, modify, or delete files
• Run shell commands that change state
• Make any changes to your system

This makes Plan Mode a safe environment for exploration. You can let Claude dig deep into your codebase without worrying about unintended side effects.

//How to Enter Plan Mode

During a session:

Press Shift + Tab twice. The first press switches to Auto-Accept Mode, the second to Plan Mode. You'll see ⏸ plan mode on at the bottom of your terminal.

Starting a new session in Plan Mode:

claude --permission-mode plan

From within Claude Code:

Just tell Claude to plan:

/plan Refactor the auth module to use JWT

Or naturally:

I want to add user roles to the application.
Let's plan this out before making any changes.

//The Planning Workflow

The best workflows involve three distinct phases:

Phase 1: Context Loading

Claude reads your codebase. It explores file structures, understands dependencies, and builds a mental model of your project. In Plan Mode, this exploration is risk-free.

Phase 2: Plan Generation

Claude creates a structured plan. This typically includes:

• Task breakdown
• Dependencies between tasks
• File modifications needed
• Potential risks or edge cases
• Execution order

Claude often writes this to a plan.md file for you to review.

Phase 3: Human Review

You read the plan. Ask questions. Request changes. Once you're satisfied, approve it.

Phase 4: Execution

Exit Plan Mode (Shift + Tab or tell Claude to proceed) and Claude executes the plan systematically.

//Why Plan Mode Matters

Shared understanding. Before any code is written, you and Claude agree on goals, constraints, and approach. No surprises.

Complexity management. Big features become a sequence of manageable tasks. Claude won't lose track halfway through.

Fewer iterations. Upfront analysis catches issues before they become bugs. Less back-and-forth.

Better output. When Claude understands the full picture before starting, the code quality is noticeably higher.

Safe exploration. You can ask Claude to investigate anything without risk. "How does authentication work in this codebase?" won't accidentally modify anything.

//Extended Thinking

Plan Mode pairs powerfully with extended thinking. Use specific phrases to trigger deeper analysis:

Example:

Think hard about how to add caching to our API
without breaking existing integrations.

Claude will spend more computation time evaluating alternatives before proposing a plan.

//When to Use Plan Mode

Multi-file refactors. When your change touches many files, plan first.

New features. Before implementing something significant, get alignment on the approach.

Codebase exploration. When you want to understand how something works without changing it.

Architecture decisions. When you're unsure of the best approach and want to evaluate options.

Code reviews. Let Claude analyze code in read-only mode and provide feedback.

Onboarding. Use Plan Mode to have Claude explain your codebase to you or new team members.

When to skip Plan Mode:

• Quick bug fixes with obvious solutions
• Single-file changes
• Simple tasks you've done before

//Practical Example

Let's say you want to add role-based access control to your app.

Enter Plan Mode:

claude --permission-mode plan

Start the conversation:

I want to add user roles (admin, member, viewer) to our application.
Roles should control access to API endpoints and UI elements.
Plan this out thoroughly before we implement anything.

Claude explores and plans:

Claude will read your auth implementation, database schema, API routes, and UI components. It might ask:

• "Should roles be stored in the user table or a separate table?"
• "Do you want role inheritance (admin inherits member permissions)?"
• "How should unauthorized access be handled—403 or redirect?"

After discussion, Claude produces a plan:

# Role-Based Access Control Implementation Plan

## Phase 1: Database Schema
- Add `role` column to users table (enum: admin, member, viewer)
- Default new users to `member`
- Migration file: `migrations/add-user-roles.sql`

## Phase 2: API Middleware
- Create `requireRole` middleware in `src/middleware/auth.ts`
- Update protected routes with role requirements
- Files: `src/routes/admin.ts`, `src/routes/api.ts`

## Phase 3: UI Access Control
- Create `RoleGate` component for conditional rendering
- Update navigation to hide admin links from non-admins
- Files: `src/components/RoleGate.tsx`, `src/components/Nav.tsx`

## Phase 4: Testing
- Add role-based test fixtures
- Test each endpoint with each role
- Files: `tests/auth.test.ts`

## Execution Order
1 → 2 → 3 → 4 (sequential, each phase depends on previous)

Review and approve:

Once you're happy with the plan, exit Plan Mode and Claude executes each phase systematically.

//Tips for Effective Planning

Be specific about constraints. "We need to maintain backwards compatibility" or "This needs to work with our existing auth system" helps Claude plan appropriately.

Ask for alternatives. "What are two or three ways we could approach this?" gets you options to choose from.

Request risk analysis. "What could go wrong with this approach?" surfaces potential issues early.

Break big plans into milestones. For large features, plan in phases. Review and approve each phase separately.

Save your plans. Having Claude write to a plan.md file creates documentation for future reference.

Plan Mode isn't about slowing down. It's about going fast in the right direction. The few minutes spent planning save hours of rework.

Start with a plan. Ship with confidence.