GPT-5.6 vs Claude Fable 5: Which One Fits Which Job
OpenAI says GPT-5.6 Sol beats Claude Fable 5 on coding at a third of the cost. Anthropic says Fable 5 leads on raw capability. Both are right. Here is which model wins which job.
An API run can cost less than one dollar. That does not make the software project a one-dollar project.
Someone still defines the task, supplies the right context, reviews the patch, runs tests, handles failures, deploys the change, and owns production. Tokens are one line in the cost model. They are still worth measuring because an unmetered pilot can turn into an unreadable monthly bill.
Prices in this article were checked on July 10, 2026 and exclude taxes. Providers can change them.
Providers price input and output tokens separately. Input includes instructions, conversation history, repository excerpts, and tool output. Output includes the model response, generated code, and in some products the reasoning tokens used to produce it.
Coding agents are input-heavy. They read files, test results, terminal errors, and diffs repeatedly. One user request can trigger many model requests.
Standard prices per million tokens in USD:
| Model | Input | Output | Important condition |
|---|---|---|---|
| OpenAI GPT-5.6 Terra | $2.50 | $15.00 | Long-context requests cost more. |
| Anthropic Claude Sonnet 5 | $2.00 | $10.00 | Introductory price through August 31, 2026. |
| Google Gemini 3.1 Pro Preview | $2.00 | $12.00 | For prompts up to 200k tokens. |
| DeepSeek V4 Pro | $0.435 | $0.87 | Cache-miss input price. |
Sources: OpenAI API pricing, Claude pricing, Gemini API pricing, and DeepSeek pricing.
This table does not rank coding quality. A model with a lower listed rate can cost more if it needs extra attempts or creates more review work.
These volumes are transparent examples, not productivity benchmarks.
| Scenario | Volume | GPT-5.6 Terra | Sonnet 5 | Gemini 3.1 Pro | DeepSeek V4 Pro |
|---|---|---|---|---|---|
| Light assistance | 150k input + 20k output | $0.68 | $0.50 | $0.54 | $0.08 |
| Heavier agent run | 500k input + 60k output | $2.15 | $1.60 | $1.72 | $0.27 |
| Large context and several iterations | 1.5M input + 150k output | $6.00 | $4.50 | $4.80 | $0.78 |
The formula is straightforward:
cost = input tokens × input rate + output tokens × output rate
Web search, sandboxes, cache storage, regional processing, and other tools can add charges. An uncontrolled retry loop pays for every failed attempt.
Platy.sk reports that 80% of programmer respondents in Slovakia earn roughly €1,717 to €4,126 gross per month.
Neither number maps directly to token pricing. An employee also brings payroll costs, equipment, management, and availability. A contractor rate includes coordination, risk, and expertise. The human also carries architectural judgment, domain context, and responsibility that the API table does not capture.
Source: Platy.sk.
The strongest cases have a clear boundary and an automated way to verify the result:
A senior engineer can supervise more work in parallel, but the operating model still needs a human in the loop. Every shipped change needs an owner and evidence.
Costs rise when the task has no defined outcome, the repository lacks tests, the context is dumped without selection, or the agent repeats the same failed approach. Review becomes the bottleneck when nobody can quickly judge domain correctness.
The cheapest model is not always the cheapest path. A measured multi-model strategy can route classification and summarization to a lower-cost model while reserving harder decisions for the model that needs fewer corrections.
Track the cost of a completed task, not the price of a million tokens:
value = hours saved − task setup − review − rework − API − operating risk
Pick ten repeated tasks for a pilot. Measure time without AI, time with AI, model usage, review comments, and regressions. After a month, you will know where the agent helps and where it simply moves work around.
If you want to run that comparison on a real workflow or repository, start with a narrow AI automation pilot. The deliverable should be measured evidence, not a promised percentage saving.
Founder and software lead at Rise.sk. He designs and delivers web applications, data systems, and automation, and writes about software decisions, AI, and digital services.
OpenAI says GPT-5.6 Sol beats Claude Fable 5 on coding at a third of the cost. Anthropic says Fable 5 leads on raw capability. Both are right. Here is which model wins which job.
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