Model Comparison

Claude Opus 5 vs Claude Fable 5: Value vs Frontier

Anthropic's new value flagship against its Mythos-class frontier model. Opus 5 lands near Fable 5 on the launch benchmarks at half the price. Here is the verified data and the honest routing answer.

By Kylian Migot · Updated July 2026 · 7 min read

Quick answer

Claude Opus 5 ($5 in / $25 out per MTok) lands near Claude Fable 5 ($10 in / $50 out per MTok) on Anthropic's launch benchmarks, within 0.5% on CursorBench 3.2, beating Fable 5's best on OSWorld 2.0, at half the cost per token. For most coding, Opus 5 is the value pick; Fable 5 is for the hardest fraction.
Claude Opus 5 price
$5 in / $25 out per MTok
Claude Fable 5 price
$10 in / $50 out per MTok
CursorBench 3.2
Opus 5 within 0.5% of Fable 5 (Anthropic)
OSWorld 2.0
Opus 5 beats Fable 5's best (Anthropic)
01

Head-to-Head: The Verified Specs

Both are Anthropic models, so unlike a cross-vendor match-up the pricing and benchmarks are directly comparable. Claude Opus 5 shipped July 24, 2026; Claude Fable 5 shipped June 9, 2026 and redeployed globally on July 1. Side by side:

Claude Opus 5Claude Fable 5
Price (per MTok)$5 in / $25 out$10 in / $50 out
ReleasedJuly 24, 2026June 9, 2026
Context windowNot published by Anthropic1M tokens (128k output)
ReasoningAdjustable effortAdaptive thinking, always on
TierFlagship (value)Frontier (Mythos-class, above Opus)
AccessClaude Code /model opusClaude Code /model fable (v2.1.170+)

Deeper single-model breakdowns live on the dedicated pages: Claude Opus 5 for coding and Claude Fable 5 for coding.

02

The Benchmarks: How Close Opus 5 Gets

The interesting numbers are the ones Anthropic framed against Fable 5 directly in the Opus 5 launch materials. Both are Anthropic's claims, not yet third-party reproduced, so treat them as provisional, but they are apples-to-apples between the two models:

BenchmarkOpus 5 vs Fable 5 (Anthropic)Cost angle
CursorBench 3.2Within 0.5% of Fable 5's peakat half the cost per task
OSWorld 2.0Beats Fable 5's best resultat ~1/3 the cost per task
Frontier-Bench v0.1Surpasses all models, >2x Opus 4.8lower cost per task than 4.8
ARC-AGI 33x the next-best model

Data verified July 24, 2026. The pattern is consistent: Opus 5 either matches or edges Fable 5 on the benchmarks Anthropic chose to publish, at a large cost discount. Where Fable 5 still wins is the very top of the hardest leaderboards and its documented 1M tokens (128k output) context window, Opus 5's window is unpublished as of launch.

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03

Cost Math: What a Story Actually Costs

Fable 5 is priced at exactly double Opus 5: $10 vs $5 per million input tokens, $50 vs $25 per million output. On a realistic agentic story, 500k input tokens of repo context and spec, 100k output tokens of code and reasoning:

500k in / 100k outClaude Opus 5Claude Fable 5
Input cost$2.50$5.00
Output cost$2.50$5.00
Story total$5.00$10.00

About $5.00 versus $10.00 per story, a 2x difference that compounds fast across a sprint of dozens of stories. Given Anthropic's own benchmarks put the two within a fraction of each other on most tasks, defaulting everything to Fable 5 is the expensive way to feel thorough. For the full Claude price ladder, see the best Claude model for coding.

04

When to Pick Which

Pick Claude Opus 5 for

Most agentic coding: feature work, multi-file changes, refactors, and review passes. Cost-sensitive parallel agent fleets where the 2x price gap compounds. Any workflow that benefits from adjustable effort, dial up for the hard stories, down for the routine ones. It is the sane new default for the Opus slot.

Pick Claude Fable 5 for

The genuinely hardest work: cross-cutting architecture refactors, multi-hour autonomous runs where one wrong turn costs more than the price gap, and spec drafting against very large repos where the 1M tokens (128k output) context window and top-of-leaderboard scores earn the premium. The frontier fraction, not the daily driver.
05

Or Route Both on One Board

The real answer is not either/or, it is routing. Default your board to Opus 5 and escalate only the one or two stories that are genuinely brutal to Fable 5. That way you pay the frontier price only where it changes the outcome, and get value-flagship economics everywhere else.

That is what AIDEN is built for: a macOS desktop app that runs your existing Claude Code CLI on a kanban board, BYOK and local-first, every story gated behind an approved spec and running on its own git branch. Assign Opus 5 to the column and bump the hard card to Fable 5, in the same project. More on the mechanics in model routing for coding agents, and the full lineup at AI models for coding.

FAQ

Is Claude Opus 5 better than Claude Fable 5?
Not outright, but it is close enough to matter. Fable 5 is the frontier Mythos-class model and still tops some benchmarks. But Anthropic reports Opus 5 landing within 0.5% of Fable 5 on CursorBench 3.2 and beating Fable 5's best on OSWorld 2.0, in both cases at a fraction of the cost per task. For most coding work Opus 5 is the better value; Fable 5 is for the hardest fraction.
How much cheaper is Opus 5 than Fable 5?
Half the price on both sides of the meter. Opus 5 is $5 in / $25 out per MTok; Fable 5 is $10 in / $50 out per MTok, exactly double. A story using 500k input and 100k output tokens costs about $5.00 on Opus 5 versus $10.00 on Fable 5.
When is Fable 5 still worth the premium?
On the genuinely hardest work: cross-cutting refactors, multi-hour autonomous runs where a wrong turn costs more than the price gap, and spec drafting against very large repos where Fable 5's 1M-token context and top-of-leaderboard scores earn their keep. For everything else, Opus 5 gives you most of the capability at half the cost.
Do Opus 5 and Fable 5 have the same context window?
Fable 5 ships a 1M tokens (128k output) window. Anthropic did not publish a context-window figure for Opus 5 at launch, so we leave it unstated rather than guess. If you rely on very large single-session context, that is a point in Fable 5's favor until Anthropic documents Opus 5's window.
Can I run both on the same project?
Yes. That is exactly how per-story model routing works: default your board to Opus 5, and escalate only the hardest one or two stories to Fable 5. AIDEN runs your Claude Code CLI on a kanban board where each story is its own session on its own git branch, so you can mix models story by story in one project.

Keep reading

Default to Opus 5, escalate to Fable 5.

AIDEN runs your Claude Code CLI on a kanban board, one session per story. Route Opus 5 to most stories and Fable 5 to the brutal one, same project. Free for one project.

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