How to Debug with AI Inside Cursor

By Carlos Montiel | Enterprise AI Specialist
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Published: 2026-07-28 | By: Carlos Montiel | Reading time: ~4 minutes

Pasting a stack trace and asking it to “fix it” produces surface-level patches. Debugging well with AI requires giving it the same context you'd give a senior teammate.

The most common mistake: insufficient context

The fastest way to get a fix that doesn't fix anything is pasting only the error message with no context. A stack trace alone tells the model where the failure happened, not why. For effective debugging in Cursor, always include: the full stack trace, the file where it occurs, and the files that call that function or provide the data that failed.

@src/services/PaymentService.php @src/controllers/CheckoutController.php This error happens intermittently in production (about 1 in 200 requests): TypeError: Cannot read property 'amount' of undefined at PaymentService.processRefund (PaymentService.php:42) at CheckoutController.refund (CheckoutController.php:118) It doesn't always fail. Investigate what condition causes 'amount' to arrive undefined instead of assuming a generic null-check fix.

Explicitly asking it to investigate the cause "instead of a generic fix" changes the response: it forces the model to reason about the data flow instead of simply wrapping the line in a defensive if that hides the symptom.

Telling symptom apart from root cause

A typical AI failure pattern in debugging is proposing the most local fix possible (adding a null-check right where it blows up) instead of tracing why the data arrived null in the first place. To force root-cause analysis, explicitly ask for the backward trace:

"Before proposing a fix, trace where the 'refund' object that reaches processRefund comes from. Follow the call chain until you find where it's first constructed, and tell me at what point it could end up missing the 'amount' field."

This usually reveals the real problem: for example, that an external webhook sometimes sends a partial payload, and the null-check in the service only hides a missing input-validation problem in the controller.

Use Composer to reproduce the bug, not just fix it

Before accepting a fix, ask for a test that reproduces the reported bug. This has two benefits: it confirms the model correctly understood the cause (if the test doesn't fail with the old code, the theory is wrong) and it leaves a permanent regression test in place.

"First write a test that reproduces this bug with the current code (it should fail). Then apply the fix and confirm the same test passes."

This order — failing test, then fix, then passing test — is more reliable than asking for a direct fix, because it quickly exposes when the AI misunderstood the problem.

Debugging intermittent and concurrency bugs

For bugs that aren't deterministically reproducible (race conditions, database connection issues, timeouts), Cursor's chat can help generate hypotheses but can't "guess" the cause without data. The effective workflow is to ask it to generate targeted additional logging, deploy it, and then analyze the real logs with the AI:

"Add temporary logging in PaymentService.processRefund that captures: the full payload received, the timestamp, and the database connection state at that moment. Use the existing logger (app/Logging/PaymentLogger), not console.log."

Once you have real production logs, paste them back into the chat for analysis — the AI is far more effective analyzing real evidence than speculating about a hypothetical race condition.

Debugging with the integrated terminal and agent mode

Composer can run commands if you grant permission, enabling a tighter debugging loop: run the test, see it fail, adjust the code, run it again, without you having to copy and paste output manually.

"Run `php artisan test --filter=RefundTest`, if it fails, adjust the code based on the error, and run it again until it passes. Show me each iteration before continuing."

Explicitly asking it to "show me each iteration before continuing" prevents the model from iterating several times without you seeing the intermediate changes — important for not losing track of what was changed and why.

When AI won't solve it alone

Bugs that depend on external state the model can't observe (specific behavior of an infrastructure version, an intermittent network issue, corrupted production data that isn't in the repo) require you to supply the evidence — logs, metrics, traffic captures. AI in Cursor drastically speeds up the "I have a hypothesis, let's verify it in code" cycle, but it doesn't replace the instrumentation and observability that only you can wire up from the production system.

Carlos Montiel
Enterprise AI Solutions Architect
Specialist in LLMs, Agents, and Orchestration
guatemalia.com/en/#contact · info@guatemalia.com

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Carlos Montiel is an enterprise AI solutions architect. He implements LLMs, Agents, RAG, and orchestrators for companies across Guatemala and Latin America. Reach out for a consultation.

Contact Carlos Montiel

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