Claude Fable 5.1 vs Claude Fable 5.2
Claude Fable 5.2 and Claude Fable 5.1 score 86.5% vs 74.7% averaged across five Vision Evals tasks (#2 and #17 of 67 models), so Claude Fable 5.2 leads overall.
- Claude Fable 5.2 wins 4 of the 5 tasks, with its widest lead on object detection (81.6% vs 61.4%).
- Claude Fable 5.2 is cheaper: $0.031 vs $0.039 overall average cost per sample.
- Claude Fable 5.1 is faster: 8.3s vs 9.3s per sample.
Roboflow Vision Evals. Full breakdown below.
Compare Claude Fable 5.1 vs Claude Fable 5.2 live
Run the same image across every model that supports a task and compare their outputs side-by-side.
These models don't share enough common tasks for a side-by-side demo. See the comparison table below for their capabilities.
Claude Fable 5.1 vs Claude Fable 5.2 on Vision Evals
Roboflow Vision Evals. Full breakdown below.
Claude Fable 5.1 vs Claude Fable 5.2 Comparison Table
Evals updated November 10, 2026Pricing updated November 10, 2026
| Property | Claude Fable 5.1 | Claude Fable 5.2 |
|---|---|---|
| Organization | Anthropic | Anthropic |
| Category | closed | closed |
| Modality | multimodal | multimodal |
| Release Date | Sep 2026 | Nov 2026 |
| Context Window | 1.0M | 1.0M |
| Parameters | Unknown | Unknown |
| License | Proprietary | Proprietary |
| Commercial use | commercial use per vendor terms | commercial use per vendor terms |
| Pricing per 1M tokens | ||
| Input $/1M | $10.00 | $8.00 |
| Output $/1M | $50.00 | $40.00 |
| Vision Tasks | ||
| Captioning | Demo | Supported |
| Classification | Demo | Supported |
| Object Detection | Demo | Supported |
| OCR | Demo | Supported |
| Visual Question Answering | Demo | Supported |
| Model Features | ||
Both support 3 more features | ||
Vision Evalsground-truth scores across 5 vision tasks, pooled at low effort | ||
| Overall | 74.7% | 86.5% |
| Avg cost / sample | $0.039 | $0.031 |
| Avg speed / sample | 8.35s | 9.33s |
| By task | ||
| Object Detection (low) | 61.4% ±0.5, Mean of 3 runs, range 61.0 to 62.0 | 81.6% ±0.3, Mean of 3 runs, range 81.2 to 81.9 |
| Object Detection (high) | 65.0% ±0.4, Mean of 3 runs, range 64.6 to 65.3 | 83.3% ±0.5, Mean of 3 runs, range 82.8 to 83.7 |
| Counting (low) | 69.4% ±2.7, Mean of 3 runs, range 66.2 to 71.6 | 86.5% ±0.0, Mean of 3 runs, range 86.5 to 86.5 |
| Counting (high) | 73.0% ±4.7, Mean of 3 runs, range 67.6 to 77.0 | 92.8% ±1.4, Mean of 3 runs, range 91.9 to 94.6 |
| Identification (low) | 97.9% ±1.6, Mean of 3 runs, range 96.9 to 100.0 | 96.9% ±0.0, Mean of 3 runs, range 96.9 to 96.9 |
| Identification (high) | 96.9% ±3.1, Mean of 3 runs, range 93.8 to 100.0 | 94.8% ±1.6, Mean of 3 runs, range 93.8 to 96.9 |
| OCR (low) | 72.9% | 79.5% |
| by category |
|
|
| OCR (high) | 75.3% | 84.8% |
| by category |
|
|
| Reasoning (low) | 72.0% ±1.3, Mean of 3 runs, range 70.9 to 73.5 | 88.1% ±1.3, Mean of 3 runs, range 86.8 to 89.4 |
| Reasoning (high) | 73.1% ±2.0, Mean of 3 runs, range 71.5 to 75.5 | 92.0% ±1.0, Mean of 3 runs, range 91.4 to 93.4 |
Claude Fable 5.1 vs Claude Fable 5.2: Overview
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. Model weights are not published.
Claude Fable 5.2 is a proprietary multimodal model from Anthropic, released on November 9, 2026. It accepts text and images and produces text, with a one million token context window and up to 128,000 output tokens. Adaptive thinking is always enabled, with an effort setting that controls reasoning. Anthropic positions Fable for demanding reasoning and long-running technical work, including coding and analysis of visual inputs.
Fable 5.2 succeeds Fable 5.1. Anthropic reports improvements in coding, reasoning, and vision, with output generation up to 30% faster than its predecessor. Fable and Mythos 5.2 share an underlying model, with additional cybersecurity and biology safeguards applied to Fable. Model weights are not publicly released.
Frequently Asked Questions
On Roboflow's Vision Evals, Claude Fable 5.2 performed better. It scores higher on 4 of the five vision tasks and averages 86.5% (#2 of 67) against 74.7% (#17 of 67) for Claude Fable 5.1. These scores measure vision capabilities only; either model may perform differently on work outside this benchmark's tasks.
No. On the Vision Evals Object Detection benchmark at low effort, Claude Fable 5.2 leads with 81.6% against 61.4%. This is the widest gap between the two models across the benchmark's tasks.
Claude Fable 5.2 is cheaper to run. Across Roboflow's Vision Evals task mix it averaged $0.031 per sample against $0.039. Claude Fable 5.1 is priced at $10.00 per 1M input tokens and $50.00 per 1M output; Claude Fable 5.2 is priced at $8.00 per 1M input tokens and $40.00 per 1M output. Actual costs depend on your image sizes, prompts, and output length.
Claude Fable 5.1 is faster. Across Roboflow's Vision Evals it averaged 8.3s per inference against 9.3s. Latency varies with image size, prompt length, and provider load, so treat these as relative rather than guaranteed figures.