Claude Fable 5

by Anthropic

Claude Fable 5 is Anthropic's most capable widely released model, with exceptional performance across software engineering, vision, knowledge work, and scientific research. It maintains focus across millions of tokens and improves its own outputs using persistent, file-based memory, compressing long-running work into far fewer sessions. The model achieves state-of-the-art vision performance, extracting precise numbers from detailed scientific figures and rebuilding a web app's source code from screenshots alone. Fable 5 posts top scores on senior-level reasoning benchmarks and, in its research-grade form, consistently produces novel, compelling scientific hypotheses when paired with domain expertise. With a 1M token context window, the model excels at extensive codebases, lengthy contracts, and comprehensive research documentation. Built-in classifiers detect a narrow set of high-risk requests and hand them off to a more constrained model, a path that on average affects fewer than 5% of sessions.

Key info

Input
Output
Features
Context window
1M
Max output
128K
Input price
$10.00 /1M
Output price
$50.00 /1M
  • US residency available
  • Zero data retention via Enterprise
  • No training by default
  • GDPR DPA available

Available routes

Claude Fable 5 runs on 3 different routes through the Opper gateway. Compare residency, ZDR, and training posture at a glance β€” full data-handling detail per route below.

ProviderRegionZero data retentionTrainingInputOutput
USEnterpriseNo$10.00$50.00
MultiEnterpriseNo$10.00$50.00
USEnterpriseNo$10.00$50.00

Uptime and availability

Claude Fable 5 runs on 3 independently monitored routes through the Opper gateway. A direct integration leaves you on one of them, the gateway serves whichever is healthy.

100%effective uptime, last 30 days
Averaged across these routes on their own, a single provider reached 94.28% over the same window.
Daily status through the gateway, which serves each request from whichever route is healthy.
3 monitored providers serve Claude Fable 5.

Measured over the last 30 days from each provider's official status feed via StatusGator. Refreshed hourly. See uptime for every provider Opper monitors.

Data handling per route

Each route hosting Claude Fable 5 has its own privacy posture, residency, and GDPR terms. Postures are maintained by Opper with a last-verification timestamp.

Anthropic β€” United StatesπŸ‡ΊπŸ‡Έ

Zero data retention is available via Opper Enterprise contract. No training on customer data. US; SCCs; DPA available.

Zero data retention
Available via Opper Enterprise contract.
Training
No training on customer data.
Logging
Abuse monitoring
Third-party access
Provider may share with subprocessors / partners
GDPR DPA
DPA available
Transfer mechanism
SCCs

Azure β€” United StatesπŸ‡ΊπŸ‡Έ

Zero data retention is available via Opper Enterprise contract. No training on customer data. GLOBAL; SCCs; DPA available.

Zero data retention
Available via Opper Enterprise contract.
Training
No training on customer data.
Logging
Abuse monitoring (30-day retention)
Third-party access
None disclosed
GDPR DPA
DPA available
Transfer mechanism
SCCs

Google Cloud β€” United StatesπŸ‡ΊπŸ‡Έ

Zero data retention is available via Opper Enterprise contract. No training on customer data. US; SCCs; DPA available.

Zero data retention
Available via Opper Enterprise contract.
Training
No training on customer data.
Logging
Abuse monitoring
Third-party access
None disclosed
GDPR DPA
DPA available
Transfer mechanism
SCCs

Benchmarks

Independent benchmark scores β€” composite indices for reasoning, coding, and math, plus individual eval scores where available.

Global rank#3 of 584 LLMs
TierFrontier
Output speed70 tok/s
First token67.21s
Intelligence Index62.1
Coding Index76.5
Reasoning & knowledge
GPQA Diamond
93%
Humanity's Last Exam
56%
Long-context reasoning
77%
Coding
SciCode
60%
Agentic & tool use
Terminal-Bench Hard
63%
τ²-Bench Telecom
99%
Math & instruction following
IFBench
63%

Get started

Call Claude Fable 5 through the Opper gateway with one API key. Let your coding agent set it up, or call it directly β€” Opper is drop-in compatible with the OpenAI, Anthropic, and Google AI SDKs.

Set it up with your agent

Copy this and paste it into a coding agent like Claude Code, Cursor or Codex and it'll wire up Opper for you.

Or call it directly

import OpenAI from "openai";
const client = new OpenAI({
apiKey: process.env.OPPER_API_KEY,
baseURL: "https://api.opper.ai/v3/compat",
});
const completion = await client.chat.completions.create({
model: "anthropic/claude-fable-5",
messages: [{ role: "user", content: "Hello" }],
});
console.log(completion.choices[0].message.content);

Compare Claude Fable 5 with…

Side-by-side on privacy, EU hosting, pricing, and benchmarks.

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