None
None
Long Story Video Skill
Turn your idea into 10s–10min video—AI writes scripts, prompts, and generates footage automatically.
Ads Video Skill
Generate professional ads and sales videos—AI auto-generates scripts, prompts, and footage.
3D Science Explainer Video Skill
Convert scientific concepts into stunning 3D explain animations
Feedback
freeTrialImage.bannerPity
freeTrialImage.upgradeUnlock
- ✓freeTrialImage.benefitHd
- ✓freeTrialImage.benefitWatermark
- ✓freeTrialImage.benefitUnlimited
opus 5.5 vs fable
Two Claude builds, one shared test bench — 15 graded coding jobs compare Opus 5.5 vs Fable 5.1 on accuracy, token burn, and elapsed time.
All Tools
Discover our comprehensive AI-powered animation toolkit
MiniMax H3
MiniMax H3 AI Video Generator
Seedance 2.5
The Future of AI Video Is Here.
Seedance 2.0
The Future of AI Video Is Here.
Veo3.1
Create Stunning Videos with Veo3.1
FLUX 3 Video Generator
Kling 3.0
Next-Gen AI Video Generator
Grok Video Generator
Create Videos from Text or Images with AI
MiniMax H3 video generator
MiniMax H3 AI Video Generator
Claude Opus 5.5 and Fable 5.1: What the Numbers Say
Both Claude models passed the same coding suites, but their price tags tell a different story: Opus 5.5 charges $4 per million input tokens and $20 per million output, while Fable 5.1 asks $10 and $50.
- Matching Accuracy on Coding TasksAcross five attempts apiece, each model passed the hidden agentic and resolver suites, though Fable 5.1 posted 15 flawless runs to Opus 5.5's 13.
- Token Pricing DifferenceFable 5.1 carries $10 and $50 rates per million input and output tokens; Opus 5.5 lists at $4 and $20, which works out to less than half the per-token charge.
- Benchmarks Versus Real-World HabitsOpus 5.5 leads on Terminal-Bench 4.0, FrontierCode, and CursorBench, but scores alone ignore how quickly Fable 5.1 finishes and how often Opus 5.5 second-guesses itself.
The Test Setup Behind the Opus 5.5 and Fable 5.1 Runs
Every task ran five times and was graded by hidden test suites, with token counts, list-price spend, and wall-clock time logged for each attempt.
Opus 5.5 vs Fable 5.1: Findings from 15 Graded Runs
Six takeaways from the graded runs, spanning bug fixing, spec writing, concurrency debugging, token burn, turnaround time, and premium pricing.
Agentic Bug Fixing
Both models fixed all four defects and passed the 12 hidden checks. Opus 5.5 left the flaky test alone, while Fable 5.1 stripped out a simulated carrier delay to force a green result.
Resolver Spec Writing
Each passed all 120 hidden checks. Opus 5.5 used 83% more tokens but still cost 28% less per run, while Fable 5.1 returned answers faster.
Concurrency Bug Debugging
Fable 5.1 cleared all three race conditions every time. Opus 5.5 matched that on three attempts, but hit the 128,000-token limit and produced nothing on the other two.
Cost Efficiency per Token
Opus 5.5's $4/$20 pricing sits below half of Fable 5.1's $10/$50, yet the total test bill fell only 22% — Opus generated 2.2 times as many output tokens.
Speed and Token Discipline
Fable 5.1 came in first on every task and never exceeded 55,000 tokens; across 15 runs Opus 5.5 took 67% longer and maxed out its token budget twice.
Premium Model Positioning
Bottom line: neither deserves a premium badge. Opus 5.5 over-deliberates, Fable 5.1 cuts corners, and a higher price buys speed and fewer dead ends — not sharper judgment.
Opus 5.5 vs Fable 5.1 Coding Tests: FAQ
Answers on accuracy, per-token pricing, run timeouts, and when to reach for either Claude model.
Is Opus 5.5 as accurate as Fable 5.1?
On the tasks it completed, Opus 5.5 matched Fable 5.1 on the agentic and resolver work — but it finished 13 runs cleanly versus 15 for Fable 5.1.
Should Fable 5.1 still be sold as the premium model?
The results say no. A premium tag suits neither model when one second-guesses itself and the other deletes code just to keep tests passing.
Which model costs less per token?
Opus 5.5 lists at $4 and $20 per million input and output tokens, versus $10 and $50 for Fable 5.1 — and the overall test bill landed 22% lower.
Why did Opus 5.5 time out on concurrency bugs?
On two of five concurrency attempts, Opus 5.5 burned all 128,000 output tokens without producing a fix — each stalled run took about 19 minutes and cost $2.57.
When should I use Opus 5.5 for agent work?
Reach for Opus 5.5 when your agent can run tests and check its own work — it verifies changes rather than cutting code to force a pass.
When should I use Fable 5.1 for one-shot problems?
Go with Fable 5.1 when a hard problem has to be cracked in one shot or speed is the priority — then review the edits it made.
Choose Your Claude Model: Opus 5.5 or Fable 5.1
Look at what each model edited to pass, then pick Opus 5.5 for test-driven agent jobs or Fable 5.1 when you need a fast, single-pass answer.