Why Cursor Claude 3.7 Sonnet Gets Stuck on One File and How to Fix It

Introduction

If you’ve been using Cursor Claude 3.7 Sonnet in the Cursor IDE composer to develop your application, you might have noticed an odd pattern: at the beginning, it acts like an architect, understanding the whole system, but as your app grows, it starts focusing on just one file—often the one you’re actively editing—while ignoring the rest of your codebase.

This can be incredibly frustrating, especially when you need changes implemented across both frontend and backend, but it seems to forget that the backend even exists. So why does this happen, and more importantly, how can you fix it?

Why Cursor Claude 3.7 Sonnet Gets Stuck on One File

The issue stems from how Claude processes information in limited context windows. Here’s what’s happening under the hood:

Initial Broad Understanding: When you first introduce a concept (e.g., a workout generator for an AI fitness app), Claude can make high-level suggestions across multiple files because it has just been given the context.
Gradual Narrowing: As your project expands, Claude loses track of earlier discussions and prioritizes the most recently referenced code. If you’re actively editing a file like WorkoutGenerator.vue, it assumes that’s the only place where changes are needed.
Context Window Limits: Unlike a human architect who remembers the whole system, Claude can only “see” a certain number of lines at a time. If your project has multiple services, models, and APIs, it simply forgets the rest unless explicitly reminded.
Frontend Bias: If you’re coding in a frontend file, Claude often assumes all logic should go there—even when backend updates are required. This is why it might generate UI changes while completely ignoring API integrations or backend logic.

How to Fix This

1. Force a Full Context Refresh

Since Claude only works with a limited memory window, you need to explicitly reintroduce key files before asking for changes.

Instead of saying: “Update the workout generator with AI selection.”
Say: “Here’s my backend file for handling AI selection. Now, make sure the AI provider logic is correctly implemented here too.”

Then, paste in the relevant backend function headers or API structure.

2. Use a Top-Down Approach

Claude responds better when given a structured breakdown of the task:

✅ DO THIS:
“Update both the frontend (WorkoutGenerator.vue) and backend (workout_service.py) to support AI model selection and provider switching. Ensure the frontend UI allows model selection, and the backend processes the request correctly.”

🚫 DON’T DO THIS:
“Add AI selection to the workout generator.”

The clearer your request, the better the results.

3. Manually Guide It Between Files

When Claude gets stuck on one file:

First, let it complete the frontend logic.
Then switch to your backend file and explicitly ask: “Now, implement the same AI logic in the backend (workout_service.py). The frontend should send requests, and the backend should process them accordingly.”

This helps nudge it in the right direction.

4. Ask for an End-to-End Plan First

If you’re making a complex change, first ask for a plan:

“List all necessary changes in both frontend and backend for AI model selection.”

Once Claude gives you a breakdown, you can execute each step separately to ensure all parts are covered.

5. Use Comments & Pseudocode as Anchors

If you already know where changes should be made, but Claude keeps ignoring them, try adding explicit TODO comments in your code:

# TODO: Implement AI model selection logic here

Then, ask:

“Look for all TODO comments in my code and implement the required logic.”

This forces it to look at all relevant sections instead of hyper-focusing on one file.

6. Copy-Paste Key Structures If Needed

If Claude keeps forgetting dependencies, you might need to manually paste the structure of key components. For example, if your frontend calls an API that Claude keeps ignoring, paste the API function signature:

def select_ai_model(user_id: str, model: str):
    """Handles AI model selection based on user preference."""

Then ask:

“Ensure the frontend correctly calls this function and processes its response.”

Final Thoughts

Cursor Claude 3.7 Sonnet is a powerful tool, but it requires guidance when working on larger projects. By understanding its limitations and using structured prompts, you can steer it back on track and ensure it doesn’t get stuck in one file.

By forcing full context refreshes, guiding it step-by-step, and using strategic prompts, you can make sure it considers your entire codebase rather than just the file you’re working in.

Have you encountered this issue? What strategies have worked for you? Let’s discuss in the comments!