Paste an Error Message or Stack Trace and Let Claude Trace It to the Root Cause

The fastest way to debug an error with Claude Code is also the simplest — just paste it in. Claude doesn't just explain the error message; it reads your actual source files at the lines referenced in the stack trace and follows the logic to find the real problem.

> ErrorException: Undefined property: App\Models\Order::$total_amount
  at app/Services/InvoiceGenerator.php:42
  at app/Http/Controllers/OrderController.php:87
  at vendor/laravel/framework/...

fix this

Claude reads InvoiceGenerator.php at line 42 and OrderController.php at line 87, checks the Order model for its attributes and relationships, looks at the migration to see what columns actually exist, and identifies whether it's a typo, a missing accessor, or a missing column — then fixes the root cause, not just the symptom.

This works for any kind of error output:

• Runtime exceptions — paste the full stack trace with file paths and line numbers
• Test failures — paste the PHPUnit/Pest/Jest output including the assertion that failed
• Build errors — paste Vite, Webpack, or compiler output
• CI failures — paste the relevant section from your CI log
• Console errors — paste browser DevTools console output

The more context you include, the better. Don't trim the stack trace — Claude uses those file paths and line numbers to navigate directly to the problem:

> the CI pipeline is failing with this output:
>
> FAIL tests/Feature/CheckoutTest.php
> ● it processes payment and creates an order
>   Expected status code 201 but received 422.
>   Response body: {"errors":{"shipping_address":["required"]}}
>
> fix the test or the code, whichever is wrong

Claude reads the test, reads the controller, checks the validation rules, and determines whether the test is missing a required field or whether the validation rule is wrong.

When in doubt, paste the whole error — Claude reads stack traces the way a senior developer does, but faster.

via Claude Code