Troubleshooting with Kiro

How to use Kiro IDE to diagnose and fix code errors, deployment failures, and AWS issues — without needing to understand the error yourself.

The Golden Rule

When something breaks, copy the error and paste it into Kiro. That's it. Kiro reads the error, understands the context of your project, and tells you exactly what to fix.

You don't need to understand the error message. You just need to give Kiro enough context:

The error message — copy the full text
Where it happened — which file, which step, which service
What you were trying to do — one sentence is enough

Fixing Code Errors

🐍 Python / Lambda Error

Your Lambda function throws an error like ImportError, KeyError, TypeError, or returns a 500 response.

What to do:

Open the failing file in Kiro (e.g. backend/lambda/app.py)
Paste the error into Kiro chat:

Paste into Kiro chat

This Lambda function is throwing an error. Here's the error from CloudWatch logs:

[paste the full error traceback here]

Fix it.

Include the full traceback — not just the last line. Kiro uses the full stack trace to pinpoint the exact issue.

🌐 Frontend JavaScript Error

Your app shows a blank page, buttons don't work, or the browser console shows errors.

What to do:

Open browser DevTools (F12 or Cmd+Option+I) → Console tab
Copy the red error messages
Open frontend/index.html in Kiro and paste:

Paste into Kiro chat

My frontend is broken. Browser console shows this error:

[paste error here]

The file is open. Fix it.

🔗 CORS Error

Browser console shows: Access to fetch at '...' has been blocked by CORS policy

What to do:

Paste into Kiro chat

I'm getting a CORS error when my frontend calls the Lambda function URL. 

Error: Access to fetch at 'https://xxx.lambda-url.ap-southeast-1.on.aws/' 
from origin 'http://my-bucket.s3-website...' has been blocked by CORS policy.

My Lambda is a Flask app using Lambda Web Adapter with response streaming. 
Fix the CORS headers in my Lambda function.

CORS errors are almost always fixed in the backend (Lambda), not the frontend. Kiro knows this and will update the right file.

Fixing Deployment Errors

🚀 GitHub Actions Failed

Your deployment shows a red ❌ in the GitHub Actions tab.

What to do:

In GitHub → Actions → click the failed run → click the failed step
Copy the error output (the red text)
Paste into Kiro:

Paste into Kiro chat

My GitHub Actions deployment failed at the [step name] step. Here's the error:

[paste the full error output]

What's wrong and how do I fix it?

☁️ SAM / CloudFormation Error

Deployment fails with errors like CREATE_FAILED, ROLLBACK_COMPLETE, or resource-specific errors.

What to do:

Paste into Kiro chat

My SAM deploy failed with this CloudFormation error:

[paste error]

My template.yaml is open. Fix it.

Common CloudFormation errors:

Error	Likely cause
`Resource already exists`	A previous failed deploy left resources behind. Delete the stack first.
`ROLLBACK_COMPLETE`	Stack is stuck. Delete it in CloudFormation console, then redeploy.
`Insufficient permissions`	IAM role missing a policy. Tell Kiro which permission is denied.
`Template format error`	YAML indentation issue. Kiro can fix this instantly.
`S3 bucket already exists`	Bucket names are global. Change the name in template.yaml.

🔑 AWS Credentials Error

Errors like ExpiredTokenException, InvalidClientTokenId, or Access Denied.

What to do:

Error	Fix
`ExpiredTokenException`	Your session token expired. Get fresh credentials from the sandbox portal and update GitHub secrets.
`InvalidClientTokenId`	Access key is wrong. Double-check the `AWS_ACCESS_KEY_ID` secret — no extra spaces.
`Access Denied`	Your IAM role doesn't have the required permission. Tell Kiro which action was denied.
`Credentials could not be loaded`	GitHub secrets are not set or named incorrectly. Check Settings → Secrets.

Credential errors are NOT code bugs — Kiro can explain them but you need to update secrets manually in GitHub.

Fixing Bedrock / AI Errors

🤖 Bedrock Model Error

Your AI feature returns an error instead of a response.

Common errors:

Error	Fix
`AccessDeniedException`	Model not enabled. Go to Bedrock → Model access → enable the model.
`ModelNotReadyException`	Model access is still pending. Wait a few minutes and retry.
`ValidationException`	Bad request format. Paste the full error into Kiro — it'll fix the API call.
`ThrottlingException`	Too many requests. Add retry logic — ask Kiro to add exponential backoff.
`ModelTimeoutException`	Request took too long. Reduce prompt length or increase Lambda timeout.
Empty response (no error)	Claude's safety filter declined. Rephrase the prompt to be more specific.

Paste into Kiro chat

My Bedrock call is failing with this error:

[paste error]

My Lambda function file is open. Fix the Bedrock API call.

General Troubleshooting Workflow

Follow this process for any error:

1 Get the error — copy the full error message from wherever it appears (GitHub Actions, browser console, CloudWatch logs, terminal)
2 Open the relevant file — open the file that's causing the issue in Kiro (Lambda function, template.yaml, index.html, deploy.yml)
3 Paste and ask — paste the error into Kiro chat with one sentence of context
4 Apply the fix — Kiro edits the file directly. Review the change.
5 Redeploy — commit the fix to GitHub and let Actions redeploy

If Kiro's first fix doesn't work, paste the NEW error back into chat. Kiro learns from each attempt and narrows down the issue.

Where to Find Error Messages

Problem	Where to look
Deployment failed	GitHub → Actions → click failed run → click failed step → read red text
App shows error in browser	Browser DevTools (F12) → Console tab → red messages
API returns error	Browser DevTools → Network tab → click the failed request → Response tab
Lambda function error	AWS Console → CloudWatch → Log groups → find your function → latest log stream
CloudFormation error	AWS Console → CloudFormation → your stack → Events tab → look for FAILED
Bedrock error	CloudWatch logs for your Lambda function (Bedrock errors appear there)

Pro Tips

Share the file + error together — Kiro is most effective when it can see both the code and the error at the same time
Use #Problems — type #Problems in Kiro chat to share all current file diagnostics
Use #Terminal — type #Terminal to share your terminal output with Kiro
Don't guess — if you're not sure what's wrong, just paste the error. Don't try to explain it yourself.
One error at a time — fix the first error, redeploy, then tackle the next one
Ask for explanation — add "explain what went wrong" if you want to learn, not just fix

Ready-to-Use Prompts

Copy any of these and replace the bracketed parts:

Generic error fix

I'm getting this error: [paste error]. The relevant file is open. Fix it.

Deployment failure

My GitHub Actions deploy failed at [step name]. Error: [paste]. What's wrong?

Runtime error

My Lambda function crashes with: [paste traceback]. Fix the bug.

Ask for explanation

Explain this error in simple terms and fix it: [paste error]

Multiple errors

I have several errors after deploying. Here's the first one: [paste]. 
Fix this one first, then I'll share the next.