• AI Fire
  • Posts
  • 🧪 Claude Opus 5.5 Changes A LOT at Each Effort Level. I Tested All of Them on One App

🧪 Claude Opus 5.5 Changes A LOT at Each Effort Level. I Tested All of Them on One App

Higher effort sounds better, but is it actually better? See exactly how Opus 5.5 behaves from lower to higher reasoning effort, including the point where extra effort starts making a real difference.

Author

Neil Phan
September 28, 2026

TL;DR: Claude Opus 5.5 produced usable apps at every effort level, but here's the thing. Higher effort did not always mean better results, and it definitely didn't always mean longer runtime either.

Extra (which maps to xhigh in the API) gave me the best balance of quality, usability, and speed. Low finished in about 12 minutes and was already surprisingly solid. Medium and High improved structure and depth. Max added more operational detail but took the longest. And here's the twist: Extra actually finished faster than High.

Ultracode also performed well, especially in task management and analytics, but it didn't clearly beat Extra overall.

One thing I need to tell you upfront: this article uses the label "Extra" for what Anthropic's API calls xhigh. Claude Code's /effort slider reads Low, Medium, High, Extra, Max, where "Extra" is xhigh and "Max" is max. So when I say Extra, I mean xhigh. Keep that in mind as you read.

Introduction

Do you really need the highest effort level in Claude Opus 5.5 to build a better app? Or are you just burning more tokens for no reason?

I wanted to find out.

So I gave Opus 5.5 the exact same prompt, assets, and task in Claude Code, and only changed one thing: the effort level, from Low all the way to Ultracode.

And wow... Opus 5.5 changes a lot depending on how much effort you give it.

So I tested every level on the same AI Mission Control Dashboard and compared the app quality, bugs, runtime, token usage, and cost.

I’ll start with the setup so every run stays as fair as possible. Let's find out.

You’ve reached the locked part! Subscribe to read the rest.

Get access to this post and other subscriber-only content.

Already a paying subscriber? Sign In.

A subscription gets you:

  • • Instant access to 700+ AI workflows ($5,800+ Value)
  • • Advanced AI tutorials: Master prompt engineering, RAG, model fine-tuning, Hugging Face, and open-source LLMs, etc ($2,997+ Value)
  • • Daily AI Tutorials: Unlock new AI tools, money-making strategies, and industry (ecommerce, marketing, coding, teaching, and more) transformations (with videos!) ($3,650+ Value)
  • • AI Case studies: Discover how companies use AI for internal success and innovative products ($1,997+ Value)
  • • $300,000+ Savings/Discounts: Save big on top AI tools and exclusive startup discounts

Reply

or to participate.