Fable 5.2 vs Opus 5.5: which model to choose for each task

Anthropic launched on November 9, 2026 Claude Fable 5.2 and at the same time reinforced that Claude Opus 5.5 remains the daily recommended engine for most coding and knowledge work. The practical question for those building with AI is simple: when is it worth paying double per token for Fable 5.2? The answer depends on the task, and the numbers Anthropic disclosed allow an honest comparison, as long as you remember that all are self reported.

In this article you will see:

• The benchmark numbers of Fable 5.2 against Opus 5.5
• Where Fable 5.2 wins and where it loses
• The price and speed difference between the two
• A recommendation by use type

Technical specs of the two models

Claude Fable 5.2 and Claude Opus 5.5 share the same family, but serve different profiles. Fable 5.2 has a context of 1 million tokens, output of up to 128 thousand tokens and accepts text and image. It costs 8 dollars per million input tokens and 40 dollars per million output tokens. Opus 5.5 costs 4 and 20 dollars respectively, half the price. Fable 5.2 also has an optional fast mode at 16 and 80 dollars, which accelerates generation up to 2.5 times.

Where Fable 5.2 wins

In the benchmarks disclosed by Anthropic, Fable 5.2 is ahead of Opus 5.5 in tasks that require long reasoning and complex code analysis.

• Remote Labor Index: 41.3 percent against 21.3 percent.
• SWE bench Pro: 93.0 percent against 89.9 percent.
• FrontierSWE v2: 69.9 percent against 62.3 percent.
• Humanity's Last Exam with tools: 74.2 percent against 67.7 percent.
• RoboDojo Sim at max effort: 64.9 percent against 27.6 percent of Fable 5.1, showing a big gain in multi step tasks.

These differences appear in long tasks, with many steps and extensive context. For software migrations, analysis of large repositories and deep reasoning problems, Fable 5.2 has a clear advantage.

Where Fable 5.2 loses

Opus 5.5 still leads in two important points.

• ProgramBench: 91.2 percent against 85.6 percent of Fable 5.2.
• GDPval AA Index: 1866 against 1831 Elo points.

In Terminal Bench 4.0, the difference is 67.6 against 66.4 percent, within the margin of error. Anthropic also admits that Fable 5.2 has fewer safety blocks, about 55 percent less than Fable 5.1, but that does not change the fact that Opus 5.5 remains cheaper and sufficient for most work.

Price per result

Fable 5.2 costs double per token. For short repetitive tasks, this cost accumulates without proportional gain. For long tasks, where a single high quality response avoids hours of rework, the higher cost can pay off. Anthropic recommends keeping Opus 5.5 as the daily engine and reserving Fable 5.2 for migrations, deep analysis and multi step problems. Fable 5.2 can also be compared with terminal results; see Terminal Bench 4.0: Claude Opus 5.5 and Sonnet 5.5 lead terminal operations with 65%. Software construction results also help; see Construction AI Leaderboard: Claude Opus 5.5 leads in 5 axes.

Recommendation by use type

• Daily tasks, code generation, review and simple refactoring: Opus 5.5.
• Software migrations, analysis of large repositories and deep reasoning: Fable 5.2.
• Cybersecurity and biomedical research in verified organizations: Mythos 5.2.
• Rapid prototyping with limited budget: Opus 5.5 or Haiku 5.5.

Limits of this comparison

All numbers are self reported by Anthropic in internal tests. There is no independent replication so far. The price difference is official, but real performance varies according to the prompt, the context and the task. Use the benchmarks as a starting point, not as final truth.

How to test both today

Fable 5.2 is available today on the Claude platform, on Amazon Web Services, on Google Cloud and on Microsoft Azure. Use the identifier claude fable 5 2. Opus 5.5 is already available on the same providers. To compare the two on your own code, run the same task on both models and compare the result, the time and the cost.

A simple method is to pick a long task, such as a module migration or analysis of a large repository, run it on both models and measure three things: whether the response solved the problem, how many tokens were used and how long it took. Repeat with three or four different tasks before deciding.

For teams that already use code agents, it makes sense to keep Opus 5.5 as the default and create a separate flow for Fable 5.2 on long tasks. That way the higher cost only shows up where the gain is real.