Claude Fable 5.1
- Family
- Claude Fable
- Released
- 2026-09-01
- Context
- 1M
- Max output
- 128K
- Architecture
- Decoder Only
- Knowledge cutoff
- 2026-06
- Specialization
- general
- Openness
- Proprietary
- License
- ProprietaryCommercial use: conditional
- Weights
- Not released
- Code
- Unknown
- Training
- Pretrained
Cheapest of 5 routes · Anthropic · cache read $0.250
About
Anthropic's generally available Mythos-class model for demanding reasoning, long-horizon agents, and ambitious coding, released September 1, 2026. Same underlying model as Claude Mythos 5.1 with cybersecurity and biology safeguards (flagged queries route to Opus 4.8 for cyber and Opus 5 for biology; those reroutes are not billed at Fable prices). Claude API id claude-fable-5-1. List price $10 per 1M input tokens and $50 per 1M output tokens; cache reads $0.25 per 1M (0.025x base input, 75% less than Fable 5's $1.00).
Providers(5)
Compare all 5Compare API pricing across 5 tracked provider routes for input and output tokens, batch, and cached reads when available.
| Provider | Input / 1M | Output / 1M | Batch in / out | Cache | Route |
|---|---|---|---|---|---|
| Anthropic | $10.00 | $50.00 | $5.00 / $25.00 | read $0.250 / 5m $12.50 / 1h $20.00 | Serverless |
| GCP Vertex AI | $10.00 | $50.00 | - | read $0.250 | Serverless |
| Microsoft Foundry | $10.00 | $50.00 | - | read $0.250 | Serverless |
| OpenRouter | $10.00 | $50.00 | - | read $0.250 | Serverless |
| AWS Bedrock | $11.00 | $55.00 | - | read $0.275 / 5m $13.75 / 1h $22.00 | Serverless |
Available via routers & gateways(16)
LiteLLM
GatewayOpen-source Python SDK and proxy server that unifies 100+ LLM APIs behind a single OpenAI-compatible interface, with load balancing, cost tracking, and configurable failover.
OpenRouter
HybridUnified hybrid gateway to 400+ models from 60+ providers via a single OpenAI-compatible API, with optional auto-routing that selects the best model per prompt.
Portkey
GatewayProduction AI gateway routing to 1,600+ LLMs with failover, load balancing, semantic caching, and guardrails; Apache 2.0 core is fully self-hostable with the complete feature set.
AIRouter
RouterCommercial LLM router that analyzes incoming requests and routes to the optimal model for cost/quality/latency via a drop-in OpenAI-compatible API, with a privacy-preserving embedding mode that avoids sending prompt content.
Amazon Bedrock Intelligent Prompt Routing
RouterAWS Bedrock's native intelligent prompt router that routes prompts between Anthropic Claude model tiers (Haiku/Sonnet) based on predicted task complexity, with no extra per-routing charge.
Azure AI Foundry Model Router
RouterMicrosoft Azure AI Foundry's native model router that uses a trained ML model to route each prompt in real time to the optimal Azure-hosted model, with Balanced/Cost/Quality mode selection and automatic failover.
Capabilities
Benchmark peer barsfor Coding
No task-mapped benchmark peers are available for this model yet.
Benchmark scores(8)
| Benchmark | Score | Version | Evaluation | Source |
|---|---|---|---|---|
| CursorBench | 51.8 | CursorBench 4.0Observed 2026-09-10 | Configuration: Fable 5.1 Max Harness: CursorBench 4.0 productized Cursor-agent workflow Evaluator: Cursor Confidence: confirmed Cost/task: $17.28 Tokens/task: 117,236 Steps/task: 128 Notes: Cursor vendor-reported configuration result; not independently reproducible. Results are subject to variance, and small score differences may not be statistically meaningful. | Source |
| CursorBench | 51.6 | CursorBench 4.0Observed 2026-09-10 | Configuration: Fable 5.1 Extra High Harness: CursorBench 4.0 productized Cursor-agent workflow Evaluator: Cursor Confidence: confirmed Cost/task: $13.01 Tokens/task: 87,294 Steps/task: 101 Notes: Cursor vendor-reported configuration result; not independently reproducible. Results are subject to variance, and small score differences may not be statistically meaningful. | Source |
| CursorBench | 49.2 | CursorBench 4.0Observed 2026-09-10 | Configuration: Fable 5.1 High Harness: CursorBench 4.0 productized Cursor-agent workflow Evaluator: Cursor Confidence: confirmed Cost/task: $9.08 Tokens/task: 58,438 Steps/task: 77 Notes: Cursor vendor-reported configuration result; not independently reproducible. Results are subject to variance, and small score differences may not be statistically meaningful. | Source |
| CursorBench | 46.8 | CursorBench 4.0Observed 2026-09-10 | Configuration: Fable 5.1 Medium Harness: CursorBench 4.0 productized Cursor-agent workflow Evaluator: Cursor Confidence: confirmed Cost/task: $7.05 Tokens/task: 45,411 Steps/task: 63 Notes: Cursor vendor-reported configuration result; not independently reproducible. Results are subject to variance, and small score differences may not be statistically meaningful. | Source |
| CursorBench | 45.1 | CursorBench 4.0Observed 2026-09-10 | Configuration: Fable 5.1 Low Harness: CursorBench 4.0 productized Cursor-agent workflow Evaluator: Cursor Confidence: confirmed Cost/task: $5.44 Tokens/task: 34,795 Steps/task: 51 Notes: Cursor vendor-reported configuration result; not independently reproducible. Results are subject to variance, and small score differences may not be statistically meaningful. | Source |
| ARC-AGI-2 | 90.0 | ARC-AGI-2 semi-privateObserved 2026-10-01 | Configuration: claude-fable-5-1 (Max) Harness: ARC Prize semi-private evaluation Evaluator: ARC Prize Foundation Confidence: confirmed Notes: ARC Prize official leaderboard data (ARC-AGI-2 semi-private), verified in https://arcprize.org/media/data/leaderboard/v2.json (generatedAt 2026-10-01T18:51Z) for modelDisplayName 'Claude Fable 5.1 (Max)'. Highest-scoring published effort selected. Discovered via Benchmark Heaven / Epoch AI mirror (lead only). | Source |
| FrontierCode 1.1 Main | 50.9 | FrontierCode 1.1 MainObserved 2026-10-05 | Configuration: claude-fable-5-1 (Medium) Harness: claude-code Evaluator: Cognition Confidence: confirmed Notes: Cognition FrontierCode 1.1 Main (100 tasks) mean@5 composite ('new_score'), verified in https://cognition.com/data/frontiercode-leaderboard/data.json (the data file behind https://cognition.com/frontiercode), retrieved 2026-10-05. Agent harness: claude-code. Highest-scoring published effort selected; timestamp is retrieval date. | Source |
| FrontierMath Tier 4 | 87.8 | FrontierMath Tier 4 v2 (private)Observed 2026-09-01 | Configuration: claude-fable-5-1 (Max) Harness: Epoch AI FrontierMath Tier 4 v2 private set Evaluator: Epoch AI Confidence: confirmed Notes: Epoch AI-run evaluation (evaluator of record), from Epoch AI Benchmarking Hub data download https://epoch.ai/data/benchmark_data.zip (file frontiermath_tier_4_v2.csv, row 'claude-fable-5-1_max', run started 2026-09-01). Epoch data is CC BY 4.0: credit 'Epoch AI, Capabilities & benchmarking, https://epoch.ai/benchmarks'. Highest-scoring Epoch configuration for this model selected; other configurations exist in the same file. Discovered via Benchmark Heaven (lead only). | Source |
Migration checks
No linked migration route is available for this model yet.
API versions
claude-fable-5-1Rankings & picks(2)
Comparison and alternatives
Browse all comparisons →Cheapest of 5 routes · Anthropic · cache read $0.250