Compare xAI: Grok 4 Fast (free) by xAI against Claude Opus 4 by Anthropic, context windows of 2.0M vs 200K, tested across 21 shared challenges. Updated February 2026.
21 challenges
Tests an AI's ability to solve a simple but potentially confusing logic puzzle
1
Sally has 1 sister. The family consists of 3 brothers and 2 sisters (Sally and one other). Each brother thus has 2 sisters, which matches the given information.
I need to work through this step-by-step.
Given information:
Since Sally is one of the sisters that each brother has, and each brother has 2 sisters total, that means th ere must be exactly 2 sisters in the family.
The 2 sisters are:
Therefore, Sally has 1 sister.
Tests an AI's randomness and creativity
Why don't skeletons fight each other? They don't have the guts!
What do you call a bear with no teeth? A gummy bear!
Why did the math book look sad? Because it had too many problems.
How do you organize a space party? You planet!
Why couldn't the leopard play hide and seek? Because he was always spotted!
All 5 are unique—no duplicates here!
Here are 5 jokes:
Why don't scientists trust atoms? Because they make up everything!
What do you call a bear with no teeth? A gummy bear!
Why did the scarecrow win an award? He was outstanding in his field!
What do you call a fake noodle? An impasta!
Why don't eggs tell jokes? They'd crack up!
All 5 jokes are unique - each one has a different setup and punchline, covering different topics (atoms/scie nce, bears, scarecrows, pasta, and eggs).
Tests an AI's ability to generate vector graphics
Tests an AI's ability to create detailed SVG illustrations of gaming hardware
Tests an AI's humor and creative writing ability
Recreate an interactive, nostalgic Pokémon battle UI in a single HTML file.
Tests an AI's ability to replicate an existing UI with Tailwind CSS
Tests an AI's ability to create interactive web elements
Tests an AI's ability to create a detailed world map in SVG format
Generate a single-page, self-contained HTML webapp using Tailwind CSS for a randomly chosen category/industry/niche.
Generate SVG art of a randomly chosen animal in a setting of its choosing.
Generate a unique and simple recipe with common ingredients.
