Getting Started with Cursor's Composer: A Developer's Guide
If you've been using Cursor but mostly sticking to the inline autocomplete, you're missing the most powerful part of the tool. Cursor's Composer is a multi-file, multi-step AI coding environment — and once you understand how to use it, your development workflow changes significantly.
What Is Composer?
Composer is Cursor's interface for giving AI complex, multi-step instructions that affect multiple files. Unlike the inline chat (which works on a single file at a time), Composer can:
- Create new files and directories
- Edit multiple files in a single operation
- Execute terminal commands
- Iterate based on error output
Open it with Cmd/Ctrl + I (or Cmd/Ctrl + Shift + I for a new Composer session).
The Mental Model
Think of Composer as a junior developer who can read your entire codebase and execute instructions precisely. Your job is to give it clear, complete instructions — not vague requests.
Bad: "Add authentication to my app"
Good: "Add NextAuth.js authentication to this Next.js 14 app. Use the App Router. Add a Google OAuth provider. Protect all routes under /dashboard using middleware. Store sessions in the database using the Prisma adapter. Create a sign-in page at /auth/signin."
The more specific the instruction, the better the output.
Key Workflows
Scaffolding New Features
Composer excels at creating the boilerplate for new features. When starting a new API endpoint, for example:
Create a NestJS module for handling user subscriptions:
- SubscriptionsModule with controller, service, and repository
- POST /subscriptions endpoint that creates a new subscription
- GET /subscriptions/:userId endpoint that returns all subscriptions for a user
- Use TypeORM with the Subscription entity (fields: id, userId, planId, status, createdAt, expiresAt)
- Include proper DTOs with class-validator decorators
- Add Swagger documentation to all endpoints
Composer will create the files, set up the module imports, and write code that follows the patterns in your existing codebase.
Refactoring Across Files
When you need to rename a concept or restructure how something works across multiple files, Composer handles it better than manual find-and-replace:
Rename the concept of "workspace" to "organization" across the entire codebase.
Update all:
- TypeScript interfaces and types
- Database entity and repository
- Service method names
- API endpoint paths
- Frontend component props
Keep "workspace" only in comments where it's needed for historical context.
Debugging with Context
Paste an error log into Composer along with the relevant code:
I'm getting this error when running the build:
[paste error]
Here's the relevant code:
[paste code]
Fix the issue and explain what caused it.
Composer will read the surrounding codebase for context, identify the root cause, and implement the fix.
Tips for Better Results
1. Give Composer access to the right context. Use @file references to point Composer at relevant files, especially if the files it needs aren't currently open.
2. Break large tasks into steps. Composer works better with 3-4 focused instructions than one massive prompt covering 20 things.
3. Review before accepting. Composer shows you a diff before applying changes. Read it. AI-generated code is usually correct but can have subtle issues.
4. Use YOLO mode carefully. YOLO mode (where Composer executes terminal commands without asking) is powerful but requires trust. Use it for well-understood operations, not for database migrations or deployments.
5. Iterate. If the first output isn't right, don't start over — refine. "The button should be on the left, not the right" is a valid Composer instruction.
What Composer Doesn't Do Well
- Complex business logic decisions. Composer writes code based on your specifications. If you don't know what the right behavior should be, it doesn't either.
- Understanding implicit constraints. If there's an important constraint you haven't told Composer about (a rate limit, a specific library requirement), it won't know.
- Perfect on first try, always. Treat Composer outputs as a strong first draft, not a final product.
Our Workflow at Oblivion
We use Composer throughout our MVP sprints. On day 2, we use it to scaffold the entire project structure from the spec. On days 3–6, it handles the boilerplate while we focus on the product decisions and edge cases. On day 7, we use it for cleanup tasks: adding error handling, writing tests, and documentation.
The result is significantly faster delivery without sacrificing code quality — because we're reviewing and guiding the AI output, not just accepting whatever it produces.
If you want to see this workflow in action, book a call and we'll walk you through how we use AI to ship faster.