Claude Opus 4 vs Claude Fable 5.1
Compare Claude Opus 4 and Claude Fable 5.1 side-by-side. See how these vision models stack up in Image Captioning, OCR, Object Detection, Open Prompt, and Classification.
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Claude Opus 4 is deprecated and can no longer be run. Details and evals are still available on its model page.
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Claude Opus 4 vs Claude Fable 5.1 Comparison Table
Evals updated September 2, 2026Pricing updated September 2, 2026
| Property | Claude Opus 4 | Claude Fable 5.1 |
|---|---|---|
| Organization | Anthropic | Anthropic |
| Category | closed | closed |
| Modality | multimodal | multimodal |
| Release Date | May 2025 | Sep 2026 |
| Context Window | 200K | 1.0M |
| Parameters | ||
| License | Proprietary | Proprietary |
| Pricing per 1M tokens | ||
| Input $/1M | $15.00 | $10.00 |
| Output $/1M | $75.00 | $50.00 |
| Vision Tasks | ||
| Captioning | Demo | |
| Chart Question Answering | ||
| Classification | Demo | |
| Document Question Answering | ||
| Image Tagging | ||
| Multi-Label Classification | ||
| Object Detection | Demo | |
| OCR | Demo | |
| Vision Language | ||
| Visual Question Answering | Demo | |
| Model Features | ||
| Foundation Vision | ||
| LLMs with Vision Capabilities | ||
| Multimodal Vision | ||
Vision Evalsground-truth scores across 6 vision tasks, pooled at low effort | ||
| Overall | Deprecated | 81.3% |
| Avg cost / sample | – | $0.035 |
| Avg speed / sample | – | 8.28s |
| By task | ||
| Object Detection (low) | – | 61.4% ±0.5, Mean of 3 runs, range 61.0 to 62.0 |
| Object Detection (high) | – | 65.0% ±0.4, Mean of 3 runs, range 64.6 to 65.3 |
| Counting (low) | – | 69.4% ±2.7, Mean of 3 runs, range 66.2 to 71.6 |
| Counting (high) | – | 73.0% ±4.7, Mean of 3 runs, range 67.6 to 77.0 |
| Identification (low) | – | 97.9% ±1.6, Mean of 3 runs, range 96.9 to 100.0 |
| Identification (high) | – | 96.9% ±3.1, Mean of 3 runs, range 93.8 to 100.0 |
| OCR (low) | – | 94.0% ±0.4, Mean of 3 runs, range 93.6 to 94.4 |
| OCR (high) | – | 93.6% ±0.2, Mean of 3 runs, range 93.5 to 93.9 |
| Data Extraction (low) | – | 93.1% ±0.5, Mean of 3 runs, range 92.8 to 93.8 |
| Data Extraction (high) | – | 93.5% ±0.5, Mean of 3 runs, range 92.8 to 93.8 |
| Reasoning (low) | – | 72.0% ±1.3, Mean of 3 runs, range 70.9 to 73.5 |
| Reasoning (high) | – | 73.1% ±2.0, Mean of 3 runs, range 71.5 to 75.5 |
Claude Opus 4 vs Claude Fable 5.1: Overview
Claude 4 Opus, released by Anthropic in May 2025, is the flagship model of the Claude 4 family, built for complex, long-horizon reasoning and advanced coding workflows. It is multimodal, supporting text (including voice), images, and tool use, and operates as a hybrid reasoning model—able to deliver quick answers in fast mode or switch to extended thinking for deeper, multi-step problem solving. With a ~200,000-token context window and a training cutoff around March 2025, it is optimized for handling large documents, long conversations, and sophisticated agentic tasks.
Positioned at the high end of Anthropic’s offerings, Opus 4 achieves state-of-the-art results on coding benchmarks like SWE-Bench (72.5%) and Terminal-Bench (43.2%). It is best suited for research, enterprise automation, and software development at scale. The model is classified at Anthropic’s ASL-3 safety level, denoting advanced oversight and safety features.
Claude Fable 5.1 is a proprietary multimodal model from Anthropic in the Mythos-class tier of the Claude 5 family, positioned above Claude Opus for demanding reasoning and long-horizon agentic work. It accepts text and images as input and returns text, with a one million token context window and a maximum output of 128 thousand tokens. Adaptive thinking is always on, and an effort parameter controls how much reasoning the model applies to a given request. Anthropic reports a reliable knowledge and training data cutoff of June 2026. Claude Fable 5.1 and Claude Mythos 5.1 share the same underlying model; the difference between them is the set of safety classifiers applied to dual-use cybersecurity and biology requests.
On the vision side, Anthropic documents improvements in reading dense charts, financial filings, and tables nested inside PDF documents, which extends the model toward document understanding, chart question answering, and spreadsheet and slide work. Reported evaluations cover agentic scientific research on Terminal-Bench-Science 0.1, agentic coding on Terminal-Bench 4.0, computer use on OSWorld 2.0, and multidisciplinary reasoning on Humanity's Last Exam. Model weights are not published.
Frequently Asked Questions
Claude Opus 4 has been deprecated by its provider and can no longer be run, so it is not part of Roboflow's current Vision Evals. This page compares the models on specs, licensing, and pricing instead.
Yes. The comparison demo on this page runs both models on the same image side by side for image captioning and OCR in the free Roboflow Playground. You can try it instantly, and a free account unlocks unlimited runs.