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Aider's Architect Mode: Plan Before You Code

Use Aider's architect mode to separate planning from implementation. Get better results on complex refactoring by letting AI propose changes before making them.

intermediate 🔄 Workflow

#The Problem

When you ask AI to make complex changes, it often rushes to implementation. The result: changes that technically work but miss the bigger picture, or worse, require multiple rounds of “no, I meant…” corrections.

#The Solution

Aider’s architect mode separates planning from implementation:

aider --architect

In this mode, Aider first proposes changes as a plan, shows you what it intends to do, and only implements after you approve.

#How It Works

#Normal Mode

You: Refactor this service to use dependency injection

Aider: [immediately starts editing files]

#Architect Mode

You: Refactor this service to use dependency injection

Aider (Architect): I'll refactor to use dependency injection. Here's my plan:

1. Create an interfaces/IUserService.ts file defining the contract
2. Extract UserRepository as a separate dependency
3. Modify UserService constructor to accept dependencies
4. Update the service factory to wire dependencies
5. Adjust tests to use mock dependencies

Files to modify:
- src/services/UserService.ts (major changes)
- src/interfaces/IUserService.ts (new file)
- src/repositories/UserRepository.ts (new file)
- src/factories/serviceFactory.ts (dependency wiring)
- tests/services/UserService.test.ts (mock setup)

Shall I proceed with this plan?

You: Yes, but skip the factory—we're using a DI container

Aider (Architect): Updated plan: [revised approach]...

#Why This Matters

  1. Catch misunderstandings early: Review the plan before any code changes
  2. Iterate on approach: Refine the strategy without undoing work
  3. Learn AI’s reasoning: See how it breaks down problems
  4. Better results: Planning leads to more coherent implementations

#Pro Tips

#Combine with Specific File Addition

aider --architect src/services/*.ts src/tests/services/*.ts

Scope the architect’s attention to relevant files for better plans.

#Use for Learning

Architect mode is great for learning codebases. Ask:

Explain how you would add rate limiting to this API

You get a detailed plan without any changes—pure documentation.

#Review Mode

Use architect mode just for code review:

Review this service for potential improvements. Don't make changes, just propose.

#When to Use

  • Complex refactoring (multiple files, architectural changes)
  • Unfamiliar codebases (learn before you change)
  • High-stakes changes (production code, critical paths)
  • Teaching (show your approach before implementing)

#When Not to Use

  • Quick fixes (single file, obvious change)
  • Routine tasks (formatting, simple additions)
  • Exploratory coding (when you want fast iteration)

Architect mode transforms AI from a eager junior dev into a thoughtful senior engineer. Use it.

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