Fable 5 vs GPT-5.6 Sol vs Grok 4.5 vs Gemini 3.1 Pro

Choosing the best AI coding model can feel like comparing four pages of benchmarks written in four different languages. Every company says its latest model is stronger, faster or better value.

But benchmarks don’t tell you which model will work best for your workflow. So I gave Claude Fable 5, GPT-5.6 Sol, Grok 4.5 and Gemini 3.1 Pro the same app to build.

Each model got one prompt and no corrections. I hid the names and scored the results before looking at time or cost.

tldr: Fable won on polish, Sol on functionality, Grok on practical value and Gemini on measured run cost.

This article is for beginners and non-technical builders who want a clear way to choose an AI coding model without getting lost in benchmark charts.

Key takeaways

🎨 Best first-pass artifact: Fable 5
✅ Best functionality: GPT-5.6 Sol
⚡ Best balance of speed, cost and capability: Grok 4.5
💸 Cheapest run in this test: Gemini 3.1 Pro
🏆 My pick for this type of everyday build: Grok 4.5

Model	Standout result	Time	Measured run cost	Main weakness
Claude Fable 5	Best blind artifact: 10/12	17m 11s	$18.27	Expensive; functionality scored 2/4
GPT-5.6 Sol	Only model with 4/4 functionality	29m 08s	$11.31	Slowest; noticeable UI/UX errors
Grok 4.5	Best combined score: 15 points	13m 00s	$1.26	Did little beyond the prompt
Gemini 3.1 Pro	Cheapest test run	15m 00s	$0.05	Minimal result: 3/12 blind score

How the blind AI coding test worked

The task was to build a live 3D world-news globe. It had to collect the 50 most recent stories from SocialCrawl, pin them to real locations, rotate, zoom, preview headlines, open summaries, link to sources and support light and dark mode.

The difficult part wasn’t drawing a globe. SocialCrawl returns the sources in text, not latitude and longitude, so each model had to work out how to turn a place mentioned in a story into a real map coordinate.

Find the prompt here 👉 https://ridio-io.notion.site/3d-world-news-map-prompt?source=copy_link

Every model received the same prompt in an empty folder, on the same machine and network. There were no follow-up messages or fixes.

I scored design, quality and completeness, and functionality while the identities were hidden. Only then did I reveal the models, times and dashboard costs.

Model specs and API pricing

These official API list prices were checked on July 28, 2026. They differ from the measured run costs because each model used a different number of tokens.

Model	Context window	Input / 1M tokens	Output / 1M tokens
Claude Fable 5	1,000,000	$10	$50
GPT-5.6 Sol	1,050,000	$5	$30
Grok 4.5	500,000	$2	$6
Gemini 3.1 Pro Preview	1,048,576	$2*	$12*

*Gemini’s standard prices rise to $4 input and $18 output when a prompt exceeds 200,000 tokens.

A cheaper token rate doesn’t guarantee a cheaper task. The number of steps and generated tokens matter too.

What each AI coding model did best

Claude Fable 5: best for polish and judgement

Fable 5 produced the strongest blind artifact at 10/12, including 4/4 for design and 4/4 for quality. It showed the most judgement around details the prompt didn’t spell out.

The trade-off was efficiency. Fable cost $18.27, the highest amount in the test, while functionality scored only 2/4.

GPT-5.6 Sol: best for working functionality

GPT-5.6 Sol was the only model to score 4/4 for functionality. It followed the brief closely and built the most reliable end-to-end workflow.

It was also the slowest at 29 minutes and 8 seconds. Noticeable interface errors meant it still needed a visual clean-up.

Grok 4.5: best practical balance

Grok 4.5 finished first in 13 minutes and cost $1.26. Solid quality and functionality pushed it to the highest combined result: 15 points.

Its weakness was proactivity. Grok 4.5 was great at following instructions, but it didn’t go beyond that. When requiring proactive decision making, it skipped the process and focused on finishing the task.

Gemini 3.1 Pro: cheapest, but very minimal

Gemini completed the run for $0.05 and finished second-fastest at 15 minutes. But it scored only 1/4 in design, quality and functionality.

That distinction matters. The lowest bill isn’t good value if you have to rebuild most of the result.

Which is the best AI coding model for you?

There isn’t one winner for every coding task. Your choice depends on whether you’re protecting quality, reliability, time or budget.

Your priority	Start with	Why
Ambiguous brief and polished design	Fable 5	Showed the strongest visual judgement and proactivity
Instruction-heavy working build	GPT-5.6 Sol	Scored highest for functionality
Fast everyday coding	Grok 4.5	Best balance in this specific test
Lowest-cost rough draft	Gemini 3.1 Pro	Produced the cheapest measured run

For this type of new build, I’d pick Grok 4.5. It reached a working first version quickly at a sensible cost.

That doesn’t make Grok the universal winner. A legacy codebase or backend-heavy system could produce a different result.

The takeaway

The best AI coding model is the one whose trade-offs match your task. For this test, that meant Grok for balance, Fable for polished output, Sol for functionality and Gemini for the cheapest scaffold.

Overall, it’s not about which AI model is technically the best performing. It’s about which one fits the best in your workflow and gets your job DONE.

Watch the full test here 👉 https://www.youtube.com/watch?v=WNwrmVOGA_o&t=5s

Which model would you have picked before the reveal?