Question 1

Is this free?

Accepted Answer

No. The sponsored offer has ended; every option is billed at normal usage rates.

Question 2

Which one should I use for a codebase I already have?

Accepted Answer

Both read and edit files. The difference people report is in how much direction each needs: Claude Code tends to explore before changing, Codex to act sooner. Send a task against your own repository and read both transcripts rather than taking either vendor's benchmark.

Question 3

Do they run the same model?

Accepted Answer

No. Claude Code runs Claude models and Codex runs GPT models, so you are comparing a pairing rather than a harness in isolation. That is the pairing you would actually ship, which is why the page compares it that way.

Question 4

Can I change the options?

Accepted Answer

Yes. Change the available models or add another compatible agent in the composer before sending. Every option uses normal usage billing.

Question 5

How does blind comparison work?

Accepted Answer

You know the candidate set, but results are labelled anonymously until you submit your preference. The original sessions remain available after reveal.

Community agent challenge

Every option is billed normally.

Your results stay yours

Benchmarks

All comparisons

Try the challenge with your task.