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Compare Opus 5.5 vs Fable 5.1

Claude Opus 5.5 vs Fable 5.1

At max effort, Opus 5.5 scored 93 and Fable 5.1 97, 3.6 points apart, under the 5 points the site counts as level. At low effort, Opus 5.5 scored 90 and Fable 5.1 95, 4.9 points apart, under the 5 points the site counts as level.

Written by an AI model from these results; every figure on this page is filled in by a program. How it was made.

Published

Side by side

Released

Opus 5.5

93/ 100

  • Low effort 90
  • Max effort 93

Level, rank 1

  • Floor45/49
  • Middle55/58
  • Top60/65

Tested . Strongest in Code.

Released

Fable 5.1

97/ 100

  • Low effort 95
  • Max effort 97

Level, rank 1

  • Floor49/49
  • Middle56/58
  • Top62/65

Tested . Strongest in Code.

Opus 5.5Fable 5.1
LowMaxLowMax
Score90939597
Web pages90809895
Code98100100100
Planning76979194
Everyday96969298
Checks passed157 of 172160 of 172164 of 172167 of 172
Median time16 s5 min 14 s20 s2 min 15 s
Median cost4.1¢76¢11¢61¢

Scored higher by 5 points or more: Fable 5.1 on building web pages, 95 to 80. Within 5 points on code, planning and architecture and everyday.

Opus 5.5’s median max effort answer took 5 min 14 s and cost 76¢ at API prices, and Fable 5.1’s median max effort answer took 2 min 15 s and cost 61¢. A median Opus 5.5 answer cost 1.2 times as much.

Of the 24 prompts at max effort, Opus 5.5 passed more checks on 3, Fable 5.1 on 2, and the two passed the same number on 19.

Where they differed

Prompts where the two passed a different number of checks at max effort, widest gap first.

  • B03 A kanban board that survives a reload

    Opus 5.5 0 of 9, Fable 5.1 9 of 9.

    Passed by Fable 5.1, missed by Opus 5.5: The page loads with no errors and has the three named columns; Adding a card works with Enter and with the Add card button; Empty or space-only titles are ignored; The counts update, and Edit and Delete work; After a reload the board is exactly as it was; Dragging moves cards between columns and reorders them, and it survives a reload; A card can be moved with the arrow keys and keeps focus; Titles like <b>hi</b> & <img ...> show exactly as typed and run nothing; No sideways scroll on a 375 px phone, even with very long titles

  • S02 A story of exactly 100 words

    Opus 5.5 5 of 6, Fable 5.1 6 of 6.

    Passed by Fable 5.1, missed by Opus 5.5: Uses the words 'kettle' and 'fog', and names the lighthouse or its keeper

  • B02 Build a dashboard from a picture of its design

    Opus 5.5 7 of 7, Fable 5.1 6 of 7.

    Passed by Opus 5.5, missed by Fable 5.1: On a phone: no sideways scroll, cards stacked, sidebar hidden until a menu button opens it

  • B04 Minesweeper in one HTML file

    Opus 5.5 9 of 9, Fable 5.1 8 of 9.

    Passed by Opus 5.5, missed by Fable 5.1: Numbers are right and an empty square opens its neighbours

  • A01 Plan a booking app for a dog groomer

    Opus 5.5 9 of 9, Fable 5.1 8 of 9.

    Passed by Opus 5.5, missed by Fable 5.1: The first phase is small and usable before payments exist

Every prompt

Checks passed on each prompt, at each setting. Each prompt links to its description.

Opus 5.5Fable 5.1
PromptLowMaxLowMax
Building web pages
B01 A landing page for a small invoicing app9 of 99 of 98 of 99 of 9
B02 Build a dashboard from a picture of its design6 of 77 of 77 of 76 of 7
B03 A kanban board that survives a reload7 of 90 of 99 of 99 of 9
B04 Minesweeper in one HTML file8 of 99 of 99 of 98 of 9
B05 Fix three layout bugs on a garden page7 of 77 of 77 of 77 of 7
Code
F01 Load more shows some posts twice and skips others7 of 77 of 77 of 77 of 7
F02 The search box shows results for an old query7 of 77 of 77 of 77 of 7
F03 Some subscriptions renew a day early7 of 77 of 77 of 77 of 7
F04 Review a pull request before merging6 of 77 of 77 of 77 of 7
F05 SQL: which customers left and came back7 of 77 of 77 of 77 of 7
F06 A contacts import that survives real CSV files9 of 99 of 99 of 99 of 9
F07 Make a slow script fast7 of 77 of 77 of 77 of 7
Planning and architecture
A01 Plan a booking app for a dog groomer7 of 99 of 99 of 98 of 9
A02 Should we switch to microservices?7 of 88 of 87 of 88 of 8
A03 Rename a column with no downtime7 of 98 of 98 of 98 of 9
A04 Turn a messy feature brief into a spec5 of 88 of 87 of 88 of 8
Everyday
W01 Text the plumber to reschedule6 of 66 of 66 of 66 of 6
I01 Check a market receipt adds up5 of 55 of 55 of 55 of 5
H02 Summing up a book that doesn't exist5 of 55 of 55 of 55 of 5
W02 Turn a messy thread into one clear update6 of 66 of 65 of 66 of 6
K02 Answer questions from a bread maker manual6 of 66 of 66 of 66 of 6
R02 Did cycling in town really double?5 of 65 of 63 of 65 of 6
P02 Filling a week of volunteer shifts6 of 66 of 66 of 66 of 6
S02 A story of exactly 100 words5 of 65 of 66 of 66 of 6

What max effort changed

  • Opus 5.5. Max passed 3 more checks, cost 16.5 times as much and took 18.9 times as long.
  • Fable 5.1. Max passed 3 more checks, cost 7.4 times as much and took 8.0 times as long.

More comparisons

Compare any two modelsEvery answer from Opus 5.5Every answer from Fable 5.1