Anthropic released Claude Fable 5.2 on 9 November 2026 for demanding coding, research, and engineering work. It still recommends Claude Opus 5.5 as the starting point for most coding and knowledge tasks. Both models have a one-million-token context window, while Fable’s standard API input and output rates are twice as high.
Key Highlights
- Both models accept text and images, return text, and support up to 128,000 output tokens per standard API request.
- Fable led on Anthropic’s FrontierCode 2.0 test at high effort. At High effort, it came close to Opus’s best score for roughly half the cost per task in that test.
- India is a supported region for the Claude API. Access and usage allowances in the Claude app depend on the plan.
What Fable 5.2 Adds and Where Opus 5.5 Fits
Opus 5.5 arrived on 22 September. Its model documentation lists long coding sessions, large refactors, and complex systems work among its uses. The Fable 5.2 release focuses on open-ended projects where the model has to decide what to try next and carry the work through several steps.
Both models adjust their reasoning as they work. Fable’s default API effort is High, while Opus starts at Medium. In Claude Code, the experimental advisor tool lets Opus consult Fable at key points, such as when planning a refactor or getting stuck on a recurring error.
Anthropic’s launch post on X introduced Fable alongside Mythos 5.2. They share the same underlying model. Fable applies stronger safeguards to cybersecurity and biology requests, while Mythos access is reserved for organisations approved through Anthropic’s verification programmes.
Where the Performance Gap Shows Up
Anthropic’s FrontierCode 2.0 results assess whether code changes would meet the standard for maintainers to merge them. Fable’s results show how much the choice of effort setting can change the comparison.
- At X high effort, Fable scored 49.1%. Opus’s best result was 45.5% at Max effort.
- At High effort, Fable scored 45.3%. Anthropic reports that this came at roughly half the per-task cost of Opus’s best run on that benchmark.
On a broader suite, Artificial Analysis scored Fable 65 and Opus 59 on its Intelligence Index at Max effort with default fallback. It reported $26.54 per task for Fable and $10.04 for Opus. Artificial Analysis says those costs reflect the mix of tasks in that suite.
Anthropic also reported that agents running an earlier version of Fable 5.2 migrated an internal service from Python to Rust. The resulting service started about 26 times as fast. For a team choosing a model, a more direct comparison is how long each takes to deliver a change that passes the same tests and review.
API Pricing and Access for Users in India
The Claude API price list separates input, output, and cache reads. On the Claude API, fast mode doubles the standard input and output rates and can generate up to 2.5 times as many output tokens per second.
| API Charge per Million Tokens | Fable 5.2 | Opus 5.5 |
| Standard input | $8 | $4 |
| Standard output | $40 | $20 |
| Standard cache reads | $0.20 | $0.20 |
| Fast mode input | $16 | $8 |
| Fast mode output | $80 | $40 |
One million uncached input tokens and 100,000 output tokens across several requests cost $12 on Fable and $6 on Opus at standard rates.
- If an agent repeatedly reads the same cached material, both models charge the same standard rate for those cache hits. New input, cache writes, and generated output are separate charges.
India appears in Anthropic’s supported API regions. In the Claude app, the launch offer lets Pro users and standard Team seats spend up to half their weekly allowance on Fable through 17 November at 1:29 p.m. IST. After that, Fable use on those plans returns to usage credits if enabled.
Before moving a workflow, check the API retention rules. Fable requires 30-day retention unless Anthropic approves an exception, while Opus supports eligible zero-data-retention arrangements. Run the same task on both models and compare cost, elapsed time, and whether the result passes your review.
FAQs
Does the one-million-token context window include the answer?
Yes. The context window includes your prompt, conversation history, files, and generated output. Leave room for the response, which has a separate 128,000-token cap per standard request.
Does fast mode make Claude reason more deeply?
Fast mode speeds up token generation at a premium rate. The effort setting controls how much work Claude puts into reasoning, so it is a separate choice.
Can Opus consult Fable without switching the main model?
Yes. In Claude Code, the experimental advisor tool lets Opus consult Fable during a task. Opus then uses that guidance to continue the session as the main model.
Can Claude Pro users keep using Fable after the launch offer?
Yes, if usage credits are enabled. After the offer ends, Fable runs on those credits for Pro users. Any unused portion of the promotional allowance expires.
Which model should I try first for a routine coding task?
Start with Opus 5.5 for a straightforward fix or refactor. If it repeatedly misses a requirement or fails tests, try Fable 5.2 on the same task.
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