Anthropic: Claude Fable 5
anthropic/claude-fable-5
Access Claude Fable 5 from Anthropic using Puter.js AI API.
Get Started// npm install @heyputer/puter.js
import { puter } from '@heyputer/puter.js';
puter.ai.chat("Explain quantum computing in simple terms", {
model: "anthropic/claude-fable-5"
}).then(response => {
document.body.innerHTML = response.message.content;
});
<html>
<body>
<script src="https://js.puter.com/v2/"></script>
<script>
puter.ai.chat("Explain quantum computing in simple terms", {
model: "anthropic/claude-fable-5"
}).then(response => {
document.body.innerHTML = response.message.content;
});
</script>
</body>
</html>
# pip install openai
from openai import OpenAI
client = OpenAI(
base_url="https://api.puter.com/puterai/openai/v1/",
api_key="YOUR_PUTER_AUTH_TOKEN",
)
response = client.chat.completions.create(
model="anthropic/claude-fable-5",
messages=[
{"role": "user", "content": "Explain quantum computing in simple terms"}
],
)
print(response.choices[0].message.content)
curl https://api.puter.com/puterai/openai/v1/chat/completions \
-H "Content-Type: application/json" \
-H "Authorization: Bearer YOUR_PUTER_AUTH_TOKEN" \
-d '{
"model": "anthropic/claude-fable-5",
"messages": [
{"role": "user", "content": "Explain quantum computing in simple terms"}
]
}'
Model Card
Claude Fable 5 is Anthropic's most capable generally available model — a publicly released, safety-hardened version of its frontier Mythos-class system, launched June 2026. It is state-of-the-art on nearly every benchmark Anthropic tested, with its lead over prior Claude models growing the longer and more complex the task.
It scores 80.3% on SWE-bench Pro, well ahead of Claude Opus 4.8 (69.2%) and GPT-5.5 (58.6%). During early testing, Stripe used it to run a codebase-wide migration in a day that would have taken a team over two months by hand. It's also Anthropic's new state-of-the-art for vision tasks and can work autonomously longer than any previous Claude model.
Priced at $10/$50 per million input/output tokens — less than half the cost of Claude Mythos Preview — it targets developers building agentic coding pipelines, vision-heavy workloads, and long-horizon autonomous tasks. Queries on a small set of sensitive topics fall back to Opus 4.8 (on average under 5% of sessions).
Context Window 1M
tokens
Max Output 128K
tokens
Input Cost $10
per million tokens
Output Cost $50
per million tokens
Input text, image, pdf
modalities
Tool Use Yes
Knowledge Cutoff Jan 2026
Release Date Jun 9, 2026
Model Playground
Try Claude Fable 5 instantly in your browser.
This playground uses the Puter.js AI API — no API keys or setup required.
More AI Models From Anthropic
Claude Opus 4.8
Claude Opus 4.8 is Anthropic's latest flagship AI model, building on Opus 4.7 with improvements across coding, reasoning, and knowledge work — at the same price point. The model excels at complex, multi-step agentic workflows including coding, financial analysis, legal reasoning, and browser-based computer use. Early testers report it outperforms both prior Opus models and GPT-5.5 across several agentic benchmarks. Notably, it's around four times less likely than Opus 4.7 to let flaws in generated code pass without flagging them. Opus 4.8 supports configurable effort levels, letting developers trade quality against speed and token cost. A fast mode operates at 2.5× speed. Priced at $5/$25 per million input/output tokens, it targets teams running autonomous agents, analysis pipelines, and long-running async workflows where reliability and judgment are critical.
ChatClaude Opus 4.8 Fast
Claude Opus 4.8 Fast is a high-speed configuration of Anthropic's latest flagship model, delivering up to 2.5x faster output token generation at significantly lower cost than previous fast variants. It runs the same Opus 4.8 model — which improves on Opus 4.7 in agentic coding (69.2% vs 64.3%), multidisciplinary reasoning with tools (57.9% vs 54.7%), and knowledge work — but optimized for lower latency. Fast mode pricing is $10/$50 per million input/output tokens, three times cheaper than fast mode for Opus 4.6 and 4.7 ($30/$150). It supports the full 1M token context window and 128k max output tokens. Choose Opus 4.8 Fast for latency-sensitive agentic pipelines, live coding sessions, and real-time workflows where throughput matters. For cost-sensitive or batch workloads, standard Opus 4.8 offers the same intelligence at half the price.
ChatClaude Opus 4.7 Fast
Claude Opus 4.7 Fast is a high-speed configuration of Anthropic's most capable model, delivering up to 2.5x faster output token generation with no reduction in quality or capabilities. It runs the same Opus 4.7 model — which scores 87.6% on SWE-bench Verified (up from 80.8% on Opus 4.6), 94.2% on GPQA Diamond, and 69.4% on Terminal-Bench 2.0 — but optimized for lower latency at premium pricing ($30/$150 per MTok). It supports the full 1M token context window and 128k max output tokens. Fast mode benefits are focused on output tokens per second, not time to first token. It is ideal for latency-sensitive agentic workflows, live coding sessions, and real-time tasks where response speed matters. For cost-sensitive or batch workloads, standard Opus 4.7 offers the same intelligence at lower cost.
Frequently Asked Questions
You can access Claude Fable 5 by Anthropic through Puter.js AI API. Include the library in your web app or Node.js project and start making calls with just a few lines of JavaScript — no backend and no configuration required. You can also use it with Python or cURL via Puter's OpenAI-compatible API.
Yes, it is free if you're using it through Puter.js. With the User-Pays Model, you can add Claude Fable 5 to your app at no cost — your users pay for their own AI usage directly, making it completely free for you as a developer.
| Price per 1M tokens | |
|---|---|
| Input | $10 |
| Output | $50 |
Claude Fable 5 was created by Anthropic and released on Jun 9, 2026.
Claude Fable 5 supports a context window of 1M tokens. For reference, that is roughly equivalent to 2,000 pages of text.
Claude Fable 5 can generate up to 128K tokens in a single response.
Claude Fable 5 has a knowledge cutoff date of Jan 2026. This means the model was trained on data available up to that date.
Claude Fable 5 accepts the following input types: text, image, pdf. It produces: text.
Yes, Claude Fable 5 supports tool use (function calling), allowing it to interact with external tools, APIs, and data sources as part of its response flow.
Yes — the Claude Fable 5 API works with any JavaScript framework, Node.js, or plain HTML through Puter.js. Just include the library and start building. See the documentation for more details.
Get started with Puter.js
Add Claude Fable 5 to your app without worrying about API keys or setup.
Read the Docs View Tutorials