Models / Claude Fable 5
Claude Fable 5
Anthropic · claude-fable-5
Best for agents
Overview
Mythos-class reasoning for autonomous knowledge work.
Claude Fable 5 is Anthropic's Mythos-class flagship, built for long-horizon autonomous work: multi-file refactors, research synthesis and agentic pipelines that run for hours. Reasoning is always on and the effort level is tunable from low to max, so you can trade latency for depth per request. It accepts text, images and documents across a one-million-token context window.
Capabilities
Call this model
curl https://open-gray.com/api/v1/chat/completions \
-H "Authorization: Bearer sk-og-v1-..." \
-H "Content-Type: application/json" \
-d '{
"model": "claude-fable-5",
"messages": [
{ "role": "user", "content": "Summarise our Q3 revenue drivers." }
]
}'
from openai import OpenAI
client = OpenAI(
base_url="https://open-gray.com/api/v1",
api_key="sk-og-v1-...",
)
response = client.chat.completions.create(
model="claude-fable-5",
messages=[
{"role": "user", "content": "Summarise our Q3 revenue drivers."}
],
)
print(response.choices[0].message.content)
import OpenAI from "openai";
const client = new OpenAI({
baseURL: "https://open-gray.com/api/v1",
apiKey: "sk-og-v1-...",
});
const response = await client.chat.completions.create({
model: "claude-fable-5",
messages: [
{ role: "user", content: "Summarise our Q3 revenue drivers." },
],
});
console.log(response.choices[0].message.content);
<?php
$payload = [
'model' => 'claude-fable-5',
'messages' => [
['role' => 'user', 'content' => 'Summarise our Q3 revenue drivers.'],
],
];
$ch = curl_init('https://open-gray.com/api/v1/chat/completions');
curl_setopt_array($ch, [
CURLOPT_POST => true,
CURLOPT_RETURNTRANSFER => true,
CURLOPT_HTTPHEADER => [
'Authorization: Bearer sk-og-v1-...',
'Content-Type: application/json',
],
CURLOPT_POSTFIELDS => json_encode($payload),
]);
$body = json_decode(curl_exec($ch), true);
echo $body['choices'][0]['message']['content'];
Pass "stream": true for server-sent events.
Worked example
A request with a 20,000-token prompt and a 2,000-token answer on Claude Fable 5:
| Input 20,000 tokens | 20.00 cr |
| Output 2,000 tokens | 10.00 cr |
| Total charged | 30.00 cr / $0.30 |
|---|