anthropic/claude-fable-5
Release date: 2026-06-09
1,000,000 context · $10.00/M input tokens · $50.00/M output tokens
Claude Fable 5 is Anthropic’s generally available Mythos-class model for autonomous knowledge work, advanced reasoning, and long-horizon coding. It supports text, image, and file inputs with text output, a 1M-token context window, up to 128K output tokens, always-on adaptive thinking, tool use, and structured outputs. Built from the same underlying model family as Claude Mythos 5 with stronger public-release safeguards, it is suited for complex software engineering, multi-step agent workflows, enterprise research, document analysis, and professional tasks that require sustained reasoning and reliability.
Pricing
Pay-per-use
No upfront costs, pay only for what you use
Try the model
API Usage
Use the following code examples to integrate with our API:
import OpenAI from 'openai';
if (!process.env.WAVESPEED_API_KEY) throw new Error('Set WAVESPEED_API_KEY');
const client = new OpenAI({
apiKey: process.env.WAVESPEED_API_KEY,
baseURL: 'https://llm.wavespeed.ai/v1',
timeout: 120_000,
maxRetries: 2,
});
try {
const response = await client.chat.completions.create({
model: 'anthropic/claude-fable-5',
messages: [{ role: 'user', content: 'Hello!' }],
});
console.log(response.choices[0]?.message?.content ?? '');
} catch (error) {
console.error('LLM request failed:', error);
process.exitCode = 1;
}import OpenAI from 'openai';
if (!process.env.WAVESPEED_API_KEY) throw new Error('Set WAVESPEED_API_KEY');
const client = new OpenAI({
apiKey: process.env.WAVESPEED_API_KEY,
baseURL: 'https://llm.wavespeed.ai/v1',
timeout: 120_000,
maxRetries: 2,
});
try {
const response = await client.chat.completions.create({
model: 'anthropic/claude-fable-5',
messages: [{ role: 'user', content: 'Hello!' }],
});
console.log(response.choices[0]?.message?.content ?? '');
} catch (error) {
console.error('LLM request failed:', error);
process.exitCode = 1;
}Model Introduction
Anthropic: Claude Fable 5
Claude Fable 5 is Anthropic’s generally available Mythos-class model for autonomous knowledge work, advanced reasoning, and long-horizon coding. It supports text, image, and file inputs with text output, a 1M-token context window, always-on adaptive thinking, tool use, and structured outputs.
Why It Looks Great
- Anthropic’s most capable widely released model for demanding reasoning and long-horizon agentic work
- Mythos-class capability made generally available with robust public-release safeguards
- 1M-token context window for large codebases, long documents, research corpora, and extended multi-turn workflows
- Up to 128K output tokens for long-form reasoning, coding, analysis, and structured generation
- Strong fit for autonomous software engineering, enterprise knowledge work, scientific analysis, and complex planning
- Vision and file input support for screenshots, diagrams, PDFs, documents, and multimodal analysis
- Always-on adaptive thinking for deeper reasoning without manual thinking-mode configuration
- Function calling and tool-use support for agentic application workflows
- Structured output support for JSON responses and schema-constrained generation
Key Features
- Context Window: 1,000,000 tokens
- Max Input: 872,000 tokens
- Max Output: 128,000 tokens
- Input: Text, Image, File
- Output: Text
- Vision: Supported
- File Input: Supported
- Function Calling: Supported
- Structured Outputs: Supported
- Adaptive Thinking: Supported, always on
- Image Generation: Not listed
- Audio Input: Not listed
- Supported Parameters: include_reasoning, max_completion_tokens, max_tokens, reasoning, response_format, stop, structured_outputs, tool_choice, tools, verbosity
Specifications
| Specification | Value |
|---|---|
| Provider | anthropic |
| Model Type | Chat Completions model |
| Model Class | Mythos |
| Architecture | text+image+file->text |
| Context Window | 1,000,000 tokens |
| Max Input | 872,000 tokens |
| Max Output | 128,000 tokens |
| Input | Text, Image, File |
| Output | Text |
| Vision | Supported |
| File Input | Supported |
| Function Calling | Supported |
| Structured Outputs | Supported |
| Adaptive Thinking | Supported, always on |
| Release | June 9, 2026 |
How to Use
- Write your prompt - describe the task, provide context, and specify the desired output format.
- Submit - the model processes your request and returns the response.
API Integration
Base URL: https://llm.wavespeed.ai/v1
API Endpoint: chat/completions
Model ID: anthropic/claude-fable-5
API Usage
Python SDK
from openai import OpenAI
client = OpenAI(
api_key="YOUR_API_KEY",
base_url="https://llm.wavespeed.ai/v1"
)
response = client.chat.completions.create(
model="anthropic/claude-fable-5",
messages=[{"role": "user", "content": "Hello!"}]
)
print(response.choices[0].message.content)cURL
curl https://llm.wavespeed.ai/v1/chat/completions \
-H "Content-Type: application/json" \
-H "Authorization: Bearer YOUR_API_KEY" \
-d '{
"model": "anthropic/claude-fable-5",
"messages": [{"role": "user", "content": "Hello!"}]
}'Notes
- Model: anthropic/claude-fable-5
- Provider: anthropic
- Best suited for autonomous knowledge work, long-horizon coding, complex reasoning, enterprise research, multimodal document analysis, and high-autonomy tool workflows
- Robust safeguards apply for high-risk domains; some sensitive requests may be refused or routed to a safer fallback model
Info
Supported Functionality
API Access Guide
Claude Fable 5 API
anthropic/claude-fable-5
Claude Fable 5 is Anthropic’s generally available Mythos-class model for autonomous knowledge work, advanced reasoning, and long-horizon coding. It supports text, image, and file inputs with text output, a 1M-token context window, up to 128K output tokens, always-on adaptive thinking, tool use, and structured outputs. Built from the same underlying model family as Claude Mythos 5 with stronger public-release safeguards, it is suited for complex software engineering, multi-step agent workflows, enterprise research, document analysis, and professional tasks that require sustained reasoning and reliability.
Input
$10 /M
Output
$50 /M
Context
1000K
Max Output
128K
Vision
Supported
Tool Use
Supported
Try Claude Fable 5 on WaveSpeedAI
Access Claude Fable 5 through our unified API — OpenAI-compatible, no cold starts, transparent pricing.
Frequently Asked Questions about Claude Fable 5
How much does Claude Fable 5 cost via the API?+
Pricing on WaveSpeedAI: $10.00 per million input tokens and $50.00 per million output tokens. Prompt caching and batch processing are billed separately and reduce effective cost on long, repetitive workloads.
What is the context window of Claude Fable 5?+
Claude Fable 5 supports up to 1000K tokens of context with up to 128K tokens of output per request.
Is Claude Fable 5 OpenAI-compatible?+
WaveSpeedAI exposes Claude Fable 5 at https://llm.wavespeed.ai/v1 through the OpenAI-compatible Chat Completions interface. Most OpenAI SDK clients work by changing the base URL and API key; optional fields depend on the selected model.
How do I get started with Claude Fable 5?+
Sign in to WaveSpeedAI, create an API key in Access Keys, then send a request to https://llm.wavespeed.ai/v1/chat/completions with the model id shown above. Check the current model catalog for availability, capabilities, and pricing.