Claude Fable 5
Overview
Claude Fable 5 is a high-capability Anthropic model available on B.AI for advanced reasoning, coding, long-context analysis, and agentic workflows. It is designed for complex tasks that require sustained context, tool-assisted execution, and high-quality structured outputs. Specific capabilities, context limits, tool support, and availability may vary by B.AI model catalog and platform configuration.
Key Features
- Advanced Reasoning: Suitable for complex analytical, technical, and professional knowledge tasks.
- Software Engineering Workflows: Designed for coding assistance, debugging, refactoring, code review, and multi-step implementation planning.
- Long-Context Tasks: Supports extended analysis across large codebases, long documents, and multi-turn work sessions when enabled by the platform configuration.
- Agentic and Tool-Assisted Workflows: Suitable for workflows that rely on tool use, function calling, code execution, MCP, or compatible agent environments.
- Multimodal Understanding: Supports text and image input for document, screenshot, chart, and diagram understanding where available.
Best Use Cases
- Complex Software Engineering: Large feature work, repository-scale refactors, migration planning, bug investigation, and code review.
- Extended Agentic Workflows: Multi-step tasks that require planning, tool use, verification, and sustained context over longer sessions.
- Research and Knowledge Work: Analysis and synthesis across technical documents, legal or financial materials, and structured research sources.
- Visual Document Analysis: Understanding screenshots, diagrams, charts, PDFs, and other image-based materials when supported by the workflow.
Capabilities and Limitations
| Capability | Description |
|---|---|
| Reasoning | Advanced reasoning for complex professional and technical tasks |
| Coding | Strong coding, debugging, refactoring, and code review capabilities |
| Agentic | Suitable for long-running tool workflows and multi-step agent tasks |
| Computer Use | Can support browser and desktop interaction through compatible tools and environments |
| Multimodal | Text and image input; text output |
| Context Window | Up to 1,000,000 tokens, subject to platform configuration |
| Max Output | Up to 128,000 tokens, subject to platform configuration |
| Tool Use | Function calling, code execution, MCP support, adaptive thinking, and compatible agent workflows |
| Multilingual | Strong multilingual performance across major world languages |
Known Limitations
- Specific capability availability may depend on the B.AI integration, Anthropic platform support, plan settings, and rollout status.
- Web access, code execution, computer use, and external actions require compatible tools or integrations.
- Image input is supported, but native audio or video input is not listed for this model.
- Public evaluations, third-party comparisons, policy behavior, and implementation details may change over time, so they are not treated as fixed guarantees in this documentation.
Credits Usage
| Model | Input (Credits/Token) | Cache Write (Credits/Token) | Cache Read (Credits/Token) | Output (Credits/Token) | Web Search (Credits/Use) | Billing Notes |
|---|---|---|---|---|---|---|
| Claude Fable 5 | 10.00 | 12.50 | 1.00 | 50.00 | 10,000 | - |
Pricing note
Prices shown in the documentation are B.AI standard reference prices for base billing purposes. B.AI may provide lower actual usage costs through top-up bonuses and account benefits. Specific prices, bonus Credits, and account benefits are subject to the platform display and final billing records.
- Prompt caching: Cache writes are charged at 1.25x base input price for the 5-minute TTL option, or 2x base input price for the 1-hour TTL option. Cache reads are charged at 0.1x base input price. Prompt caching requires a minimum of 1,024 tokens.