STEALTHMARK · HEAD TO HEAD

All comparisons ↗

Claude Fable 5.2 vs Claude Opus 5.5

Claude Fable 5.2 leads Claude Opus 5.5 by 7.2 points on StealthMark, 79.8 to 72.6. It leads on 8 of 9 benchmarks, including both games, and Claude Opus 5.5 on 1. Claude Fable 5.2 scores higher on Newton's Mirror, with its largest category advantage in reflections.

See the difference ↘
All results ↗
All results ↗

Overall StealthMark

79.8/100Overall rank 1/57
72.6/100Overall rank 3/57

General Intelligence

81.7/100
71.3/100

Visual Intelligence

76.0/100
75.0/100

Reasoning efficiency

How many reasoning tokens a model needs for the quality it delivers.

Single-step reasoning How much it reasons to understand a task

Multi-step reasoning How much it keeps reasoning as a task goes on

  • Claude Opus 5.5

Cost efficiency

How much Performance you get for your money.

  • Claude Fable 5.2Not measured

BENCHMARK BY BENCHMARK

Where each model leads

  • Claude Fable 5.2
  • Claude Opus 5.5
  • Other models
  • Median

DATASHEET

Specs and pricing

  • Claude Fable 5.2
  • Claude Opus 5.5
  • Other models
  • Median
PricePer 1M output tokens, input below
Claude Fable 5.2: No list priceClaude Opus 5.5: $20$4 input
Context windowTokens per request, max output below
Claude Fable 5.2: Not publishedClaude Opus 5.5: 1M128K max output
Output speedTokens per second, our measurement
Claude Fable 5.2: Not measuredClaude Opus 5.5: 166tokens/s
Developer
Not publishedAnthropic
Released
Not published22 Sep 2026
Origin
Not publishedUnited States
Input → output
Not publishedText, image → text

Full datasheets, every price and sourceClaude Opus 5.5 ↗

Anticipating threats and planning ahead. Collect coins while avoiding ghosts. Ghosts move before the player each turn, and collisions cost a life. 3 levels in sequence, up to 66 turns in total. Earlier moves and outcomes carry forward, testing learning across levels.

Claude Fable 5.2 77.2/100Rank 2/53

Survived 3 of 3
Foresight: complete playing field
Level 318 ptsTurn 20 / 20

Claude Opus 5.5 66.3/100Rank 6/53

Survived 3 of 3
Foresight: complete playing field
Level 39 ptsTurn 20 / 20

Points per level

LevelClaude Fable 5.2Claude Opus 5.5
Level 1Second Thoughts
27 ptsSurvived
27 ptsSurvived
Level 2Pressure Pot
12 ptsSurvived
11 ptsSurvived
Level 3Hide or Flight
18 ptsSurvived
9 ptsSurvived

Cooperative planning and learning from experience. Coordinate two robots to push numbered cores onto matching sockets. Pressure plates hold doors open; moving either robot uses one turn. 5 levels in sequence, up to 152 turns in total. Earlier moves and outcomes carry forward, testing learning across levels.

Claude Fable 5.2 100.0/100Rank 1/54

Cleared 5 of 5
Latch: complete playing field
Level 520.8 ptsTurn 26 / 40

Claude Opus 5.5 87.6/100Rank 2/54

Cleared 5 of 5
Latch: complete playing field
Level 520.6 ptsTurn 27 / 40

Points per level

LevelClaude Fable 5.2Claude Opus 5.5
Level 1Hold the door
5.2 ptsCleared
5.2 ptsCleared
Level 2Crossfeed
10.2 ptsClearedFinished early · 1 beacon left
10.2 ptsClearedFinished early · 1 beacon left
Level 3Relay vault
19.2 ptsCleared
19.2 ptsCleared
Level 4Passing bay
18.2 ptsClearedFinished early · 3 beacons left
18.2 ptsClearedFinished early · 3 beacons left
Level 5Second thoughts
20.8 ptsCleared
20.6 ptsCleared

Newton's Mirror

Same task instructions

Physics, perspective and recursive reflections, tested together. Explore the test ↗

The judgment

Claude Fable 5.2

The composition closely preserves the principal camera relationships. Visible cyan contact, elongated crimson coating and separate airborne black paint support the required interaction sequence, with a small crimson transport overshoot. Correct broad mirror placement coexists with major omissions in nested spherical imagery and simplified emitter mapping. Core score: 105.5/170; floor-damage reward: 0/10; combined total: 105.5/180.

Claude Opus 5.5

Open lateral sightlines, first reflected silhouettes and near-field planar panel placement are convincing. Missing outer chains, truncated repetitions and absent nested spherical room and emitter imagery remain the main weaknesses.

Score breakdown

CategoryClaude Fable 5.2Claude Opus 5.5
State at 600 ms24.0/2524.0/25
Camera and placement15.0/1515.0/15
Reflections80.0/12055.0/120
Materials and scale8.5/109.0/10
Floor-damage reward0.0/100.0/10

Benchmark task

A spinning metal sphere and paint in a mirrored room test physical reasoning, perspective and consistency across repeated reflections.

Selfie

Same task instructions

Visual construction and creative interpretation.

The judgment

Claude Fable 5.2

The compact mantle, eight curling rays and quiet face closely realize the requested living emblem. Controlled arm contours, coherent overlaps and restrained ornament give the design character. Shallow depth, ribbon-like arm modeling and repeated highlight bands limit anatomical and lighting complexity without compromising the intact silhouette.

Claude Opus 5.5

The centered coral squid has a friendly, restrained expression and a balanced radial silhouette within a cream arch. Smooth curves and soft shading give it an appealing matte finish. The mantle is more elongated than compact, the upper arms are visually ambiguous, and the two hanging tentacles read somewhat like legs. Clean execution supports a strong stylized illustration.

Score breakdown

CategoryClaude Fable 5.2Claude Opus 5.5
Task & likeness9.0/108.0/10
Anatomy & construction7.5/107.5/10
Space & placement7.0/108.0/10
Light & reflections7.0/107.5/10
Purposeful detail6.5/107.0/10
Artistry & character6.5/107.0/10
Materials & effects7.0/107.0/10
Visual integrity8.5/108.5/10

Benchmark task

A coral squid with spreading arms tests connected anatomy, balanced composition and soft surface shading.

Mona Lisa

Same task instructions

Precise visual recall and portrait reconstruction.

The judgment

Claude Fable 5.2

A developed illustrative portrait with controlled facial shading, connected limbs, layered scenery and distinct aged-paint and gold effects. Its frontal torso, conspicuous smile and flattened fingers limit replication and anatomical precision. Decorative finish is stronger than the underlying seated construction.

Claude Opus 5.5

The portrait preserves the recognizable composition, dark veil, folded hands and distant landscape. Replication is limited by the elongated face and neck, conspicuous eyes and simplified smile. Hands remain connected but their rounded fingers and wrists lack convincing anatomy. Restrained colors create cohesion; shallow modeling and pervasive mottling weaken volume and painterly subtlety.

Score breakdown

CategoryClaude Fable 5.2Claude Opus 5.5
Task & likeness6.5/106.5/10
Anatomy & construction6.0/105.5/10
Space & placement6.0/106.5/10
Light & reflections6.5/106.5/10
Purposeful detail6.0/106.5/10
Artistry & character6.5/106.0/10
Materials & effects7.5/107.0/10
Visual integrity7.5/107.0/10

Benchmark task

An SVG interpretation of the Mona Lisa tests facial likeness, anatomy and the composition of a familiar portrait.

Beach

Same task instructions

Creativity, perspective and visual beauty.

The judgment

Claude Fable 5.2

A lively sunset beach with clear playful activity, purposeful small details and developed water reflections. Layering and supported placements hold the scene together. Schematic anatomy and the turtle's overhead viewpoint limit construction, space and artistry, while atmospheric and surface effects show greater refinement.

Claude Opus 5.5

A lively, well-composed beach illustration with rich sunset colors, recognizable animals and appealing accessories. The sun reflection establishes a strong central focus. Clean silhouettes and small details reward inspection, though simplified animal construction, uneven contact shadows and mostly flat materials limit depth and realism.

Score breakdown

CategoryClaude Fable 5.2Claude Opus 5.5
Task & likeness9.0/108.5/10
Anatomy & construction8.0/107.5/10
Space & placement7.5/107.0/10
Light & reflections8.5/107.5/10
Purposeful detail8.5/107.5/10
Artistry & character8.0/108.0/10
Materials & effects7.5/106.5/10
Visual integrity8.0/108.0/10

Benchmark task

A busy shoreline at sunset tests scene composition, animal forms and the relationship between light and water reflections.

Ground Truth

Same task instructions

Physical reasoning, light and visual reconstruction.

The judgment

Claude Fable 5.2

This benchmark has not been assessed yet.

Claude Opus 5.5

This benchmark has not been assessed yet.

Benchmark task

A plank, computer mouse and blueberry in a steel room test physical stability, spatial relationships, materials and lighting.

Raccoon

Same task instructions

Scene composition and interacting subjects.

The judgment

Claude Fable 5.2

A controlled action illustration with expressive animals, demonstrated riding and steering, and an energetic layered wake. Purposeful small features and articulated poses strengthen the drawing. Simplified extremities, shallow character volume and limited physical lighting remain its principal constraints.

Claude Opus 5.5

The masked raccoon clearly rides the dog's back, and the dog's forward paw reaches the steering grip. Expressive faces, vivid colors and sweeping wakes create an appealing illustration. Connected limbs remain schematic, as does the small steering assembly. The broad hull and flat foam weaken water contact; the glowing sun lacks a corresponding reflection or convincing cast shadows.

Score breakdown

CategoryClaude Fable 5.2Claude Opus 5.5
Task & likeness8.5/108.5/10
Anatomy & construction8.0/107.5/10
Space & placement7.5/107.5/10
Light & reflections7.0/106.0/10
Purposeful detail8.5/108.5/10
Artistry & character8.0/107.0/10
Materials & effects7.5/107.0/10
Visual integrity8.0/108.0/10

Benchmark task

A jet-ski scene pairs a canine driver with a raccoon passenger. It tests the placement and contact of interacting subjects, along with vehicle construction.

Pelican

Same task instructions

Subject construction and spatial relationships.

The judgment

Claude Fable 5.2

A strong illustration with an expressive pelican, readable riding contacts and carefully constructed bicycle details. Layered plumage, basket weave and coastal scenery reward inspection. Continuous attachments support the action, while limited visible leg articulation, modest volume and weakly directional foreground lighting constrain physical sophistication.

Claude Opus 5.5

The recognizable pelican, orderly bicycle wheels and harmonious sunset create an appealing illustration. Both legs connect to the body and reach pedals; no clear detached or inverted parts appear. Steering contact and seating support are less convincing, while the drivetrain remains schematic. Crisp outlines give a clean finish, but limited shading and flat surfaces leave the scene with modest depth.

Score breakdown

CategoryClaude Fable 5.2Claude Opus 5.5
Task & likeness9.0/108.5/10
Anatomy & construction8.0/108.0/10
Space & placement7.5/107.0/10
Light & reflections6.5/106.0/10
Purposeful detail8.0/108.0/10
Artistry & character7.5/107.5/10
Materials & effects7.0/106.0/10
Visual integrity8.0/108.5/10

Benchmark task

A cycling pelican tests anatomy, riding posture and contact between the bird and the bicycle.