GPT-5.6 Sol vs. Claude Fable 5: Benchmarks, Price and Hands-on

The GPT-5.6 Sol and Claude Fable 5 are currently fighting for the frontier model crown.

The Fable 5 has a slight edge in general ingenuity, while the Sol bounces back with strong coding performance, fast processing and very low prices. In fact, the GPT-5.6 Sol is priced closer to the Claude Opus 4.8 than the Fable 5, which makes this comparison even more interesting.

Another model promises critical thinking. One provides near-border functionality at a more realistic cost.

So, which model should you really use?

What is GPT-5.6 Sol?

GPT-5.6 Sol is OpenAI’s flagship model for coding, research, tooling and complex workflows.

For hard problems, it supports massive inference, which allows the model to use more computing power before responding. Its ultra mode goes further by deploying multiple agents in parallel, making it better suited for large coding tasks, intensive research and multi-step projects.

Read more: GPT-5.6: Sol, Terra, and Luna

What is Claude Fable 5?

Claude Fable 5 is a publicly available model of Anthropic, built with complex thinking and long-term agent work.

Within Claude Code or Managed Agents, it can schedule multi-step tasks, send work to sub-agents, review intermediate results and refine its own output. That makes it especially useful for large coding projects, intensive research and assignments that require minimal human supervision.

Read more: Myth 5: Myth (os) or Reality

Price Comparison

API prices per million tokens:

Sol costs half the input and 40% less output.

Both models offer nearly a million core tokens and up to 128,000 output tokens. The Sol core window is a bit bigger at 1.05 million tokens.

There is one catch. Sol applications exceeding 272,000 input tokens are accepted high prices for every request.

Winning prices: GPT-5.6 Sol

For normal workload, it is not closed. Not only is Sol high limit but it also offers free to use token resets from time to time:

Something Anthropic can clearly learn from!

Manual Comparison

In order to compare GPT-5.6 Sol and Claude Fable 5 properly, I used the same information, new dialogs and default thinking settings for both models.

Results were judged on following instructions, accuracy, completeness and presentation.

Exercise 1: Build a Web Application

These tests evaluate front-end coding, design quality and functional integrity.

Notify:

Build a responsive personal finance dashboard as a single HTML file.
Requirements:
- Use only HTML, CSS and vanilla JavaScript
- Include cards for income, expenses, savings and investments
- Add an interactive monthly spending chart
- Add a transaction table with search and category filters
- Include light and dark modes
- Use realistic sample data
- Make the design clean and suitable for a modern fintech product
- Return the complete working code in one file

GPT 5.6 Sol Answer:

It took the model 6 minutes and 30 seconds to respond with the web page you requested. Here it is:

Answer from Claude Fable:

It took the model 3 minutes and 10 seconds to respond with the desired web page. Here it is:

Exercise 2: Data Analysis and Business Consulting

This test assesses analytical depth, numerical accuracy and the ability to generate useful recommendations.

Notify:

You are a senior data analyst reviewing the quarterly performance of an e-commerce company.
Quarterly data:
Q1:
Revenue: $2.4 million
Orders: 48,000
Conversion rate: 2.8%
Customer acquisition cost: $31
Repeat purchase rate: 22%
Q2:
Revenue: $2.7 million
Orders: 51,000
Conversion rate: 3.1%
Customer acquisition cost: $36
Repeat purchase rate: 24%
Q3:
Revenue: $2.9 million
Orders: 54,000
Conversion rate: 3.4%
Customer acquisition cost: $43
Repeat purchase rate: 23%
Q4:
Revenue: $3.1 million
Orders: 56,000
Conversion rate: 3.3%
Customer acquisition cost: $51
Repeat purchase rate: 20%
Analyse the company’s performance.
Include:
- The three most important trends
- Any warning signs
- Likely causes behind the changes
- Five actions the company should take next quarter
- A concise executive summary
Do not simply repeat the numbers. Derive useful business insights from them.

GPT 5.6 Sol Answer:

The model took 1 minute and 20 seconds to respond with:

Click here to view the full response

Answer from Claude Fable:

The model took a minute to respond with:

Click here to view the full response

Exercise 3: Introduction Creation

This test evaluates the content structure, visual judgment and quality of the material delivered by experts.

Notify:

Create an eight-slide investor presentation for an AI-powered recruitment platform.
The platform:
- Screens job applications
- Matches candidates with suitable roles
- Generates structured interview questions
- Provides hiring analytics
- Targets mid-sized technology companies
Include:
1. Title slide
2. Problem
3. Solution
4. Product workflow
5. Market opportunity
6. Business model
7. Competitive advantage
8. Closing slide
Use realistic sample numbers where required.

GPT 5.6 Sol Answer:

It took Sol 4 minutes and 38 seconds to answer the question by saying:

Answer from Claude Fable:

It took Fable 5, 2 minutes and 30 seconds to answer the question with:

The decision

The main difference between the two should be the usage limits. The GPT 5.6 Sol never wore out, no matter how long I had been using it. Claude Fable 5 on the other hand, has exceeded the limit of use. 3-4 conversations and I was greeted with:

Considering the fact that Fable 5 is available until July 19th while Sol is available forever for all paid users and that the price of Fable 5 is 2-3 times. But it takes your time. I mean a most of the time!

On average it took sol twice the time it took Fable 5 to answer the same question (with the same answer quality).

GPT-5.6 Sol vs Claude Fable 5: Benchmarks

The Claude Fable 5 is a bit limited in general intelligence, but the GPT-5.6 Sol is a powerful recording agent.

The results of the article are classified. Fable leads the Artificial Analysis Intelligence Index by one point, while Sol holds a three-point advantage in the Coding Agent Index. In general thinking, the models work effectively on the neck and neck. For active software development work, Sol has a clear lead.

Sol wins more code tests

Sol takes the lead DeepSWE again Terminal-Bench v2while Fable finished one point ahead SWE-Atlas-QnA. Passing two out of three tests gives Sol the profile of a powerful coding agent.

Better performance at a lower cost

Sol’s average inspection cost is $7.08 per transactioncompared to $11.80 for 5 legend. That makes Sol easy 40% cheaperit reinforces its advantage for teams using coding agents at scale.

Legend analyzes better but Sol presents better

AA-Briefcase shows a very different result. Fable gets a high Elo score and clearly leads in analysis quality. Sol, however, scores very highly for presentation, suggesting that it is better at converting its work into clear, usable results.

The conclusion

Here’s what became clear:

• GPT-5.6 Sol is slow but cheap.
• Claude Fable 5 is better for long, complex tasks.
• Sol responds well to feedback and repetition.
• Fiction requires little supervision once the work is defined.

For many users, GPT-5.6 Sol is a better choice. It approaches Fable’s ingenuity while providing better coding performance at a much lower cost.

Select The legend of Claude 5 when the work is complex enough to justify the additional cost, especially if you want to give the project and come back later.

A simple way to put it:

Sol is the model you work with. A legend is a model you work on by hand.

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