STEALTHMARK · HEAD TO HEAD

All comparisons ↗

Claude Fable 5.1 vs Crouton Alpha

Claude Fable 5.1 leads Crouton Alpha by 15.0 points on StealthMark, 63.0 to 48.0. It leads on 8 of 9 benchmarks, including Latch, and Crouton Alpha on 1, including Foresight. Claude Fable 5.1 scores higher on Newton's Mirror, with its largest category advantage in reflections.

See the difference ↘
All results ↗
Model guide ↗

Overall StealthMark

63.0/100Overall rank 7/56
48.0/100Overall rank 23/56

General Intelligence

60.6/100
43.5/100

Visual Intelligence

67.1/100
56.0/100

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

Cost efficiency

How much Performance you get for your money.

  • Crouton AlphaNot measured

Open or local

BENCHMARK BY BENCHMARK

Where each model leads

  • Claude Fable 5.1
  • Crouton Alpha
  • Other models
  • Median

DATASHEET

Specs and pricing

Claude Fable 5.1 scores higher on StealthMark. Crouton Alpha runs 44% faster in our speed test.

  • Claude Fable 5.1
  • Crouton Alpha
  • Other models
  • Median
PricePer 1M output tokens, input below
Claude Fable 5.1: $50$10 inputCrouton Alpha: No list price
Context windowTokens per request, max output below
Claude Fable 5.1: 1M128K max outputCrouton Alpha: Not published
Output speedTokens per second, our measurement
Claude Fable 5.1: 122tokens/sCrouton Alpha: 17544% fastertokens/s
Developer
AnthropicNot published
Released
1 Sep 2026Not published
Origin
United StatesNot published
Input → output
Text, image → textNot published

Full datasheets, every price and sourceClaude Fable 5.1 ↗

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 5.1 34.2/100Rank 41/522 of 3 levels

2 of 3 played
Foresight: complete playing field
Level 38 ptsTurn 17 / 20

Crouton Alpha 32.3/100Rank 29/52

Survived 1 of 3
Foresight: complete playing field
Level 39 ptsTurn 20 / 20

Points per level

LevelClaude Fable 5.1Crouton Alpha
Level 1Second Thoughts
21 ptsOut of lives
3 ptsOut of lives
Level 2Pressure Pot
Pending
7 ptsOut of lives
Level 3Hide or Flight
8 ptsOut of lives
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 5.1 82.6/100Rank 6/53

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

Crouton Alpha 59.5/100Rank 24/53

Cleared 4 of 5
Latch: complete playing field
Level 520.2 ptsTurn 29 / 40

Points per level

LevelClaude Fable 5.1Crouton Alpha
Level 1Hold the door
5.2 ptsCleared
5.2 ptsCleared
Level 2Crossfeed
9.8 ptsCleared
9.4 ptsCleared
Level 3Relay vault
19.2 ptsCleared
11.2 ptsFinished early
Level 4Passing bay
18.2 ptsClearedFinished early · 3 beacons left
18.2 ptsClearedFinished early · 3 beacons left
Level 5Second thoughts
20.6 ptsCleared
20.2 ptsCleared

Newton's Mirror

Same task instructions

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

The judgment

Claude Fable 5.1

The broad paint sequence, bilateral near-field sphere arrangement, overlaps and diminishing panel repetitions are recognizable; crimson is slightly too low. Small paint scale and basic shading provide material cues, although the steel response remains soft. Inaccurate light projections, missing outer chains and incomplete nested room imagery remain the principal limitations.

Crouton Alpha

The artwork establishes approximate central placement, a separate airborne black blob, and basic wall and floor sphere images. Its defining weaknesses are the largely absent recursive reflection system, missing emitter mappings, satin steel appearance and unresolved paint interaction. The black lateral wedges do not establish a separate viewport, and the hidden floor contact does not establish a gap. The category values remain unchanged.

Score breakdown

CategoryClaude Fable 5.1Crouton Alpha
State at 600 ms24.0/2519.0/25
Camera and placement14.0/1511.0/15
Reflections48.0/12021.5/120
Materials and scale7.5/106.0/10
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

Different task instructions

Visual construction and creative interpretation.

The judgment

Claude Fable 5.1

The coral palette, friendly face, matte shading and cream arch create a coherent emblem. However, the mantle is elongated rather than compact, and the appendages spread mostly sideways and downward instead of forming an evenly spaced, flower-like starburst. Two thin hanging appendages weaken the thick-arm motif. Clean contours and balanced framing support the simple design.

Crouton Alpha

A cheerful, readable cartoon captures the crouton's signature expression and many specific accessories. Coherent cube geometry and foreground foreshortening support the selfie. Simple construction and flat material treatment limit its sophistication, while the tipping raft, advancing soup and unnoticed soaking remain insufficiently clear.

Score breakdown

CategoryClaude Fable 5.1Crouton Alpha
Task & likeness6.5/106.5/10
Anatomy & construction7.0/105.5/10
Space & placement7.5/106.5/10
Light & reflections6.5/105.5/10
Purposeful detail6.0/107.0/10
Artistry & character7.0/105.0/10
Materials & effects6.5/105.5/10
Visual integrity8.0/107.5/10

Benchmark task

Claude Fable 5.1

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

Crouton Alpha

Character scenes test expression, anatomy, materials and coherent visual construction.

Mona Lisa

Same task instructions

Precise visual recall and portrait reconstruction.

The judgment

Claude Fable 5.1

The dark clothing, crossed hands and hazy landscape establish the Mona Lisa composition. Replication is limited by the frontal, elongated face, wide eyes and simplified smile. Rounded, parallel fingers and unclear wrist transitions weaken the hands. Warm facial shading gives some volume, but broad garment shapes and scattered crack marks substitute for convincing folds and painterly detail.

Crouton Alpha

A recognizable, coherent simplification with readable eyes, a restrained smile and modest facial volume. Frontal symmetry, an oversized head, capsule-like hands and geometric scenery substantially limit likeness, anatomy and depth. Clean contours preserve basic integrity but do not establish sophisticated construction or finish.

Score breakdown

CategoryClaude Fable 5.1Crouton Alpha
Task & likeness5.5/104.5/10
Anatomy & construction6.0/104.0/10
Space & placement6.0/104.5/10
Light & reflections6.0/105.0/10
Purposeful detail5.0/104.0/10
Artistry & character5.5/104.5/10
Materials & effects6.0/104.0/10
Visual integrity6.5/106.0/10

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 5.1

The colorful sunset, layered shoreline, animals, kite and beach toys fulfill the lively beach brief. Clean silhouettes and a balanced composition give the illustration character. Construction is simplified: the umbrella resembles a segmented fan, dolphins have weak water interaction, and the sun’s reflection forms a rigid widening wedge. Flat surfaces and sparse contact shadows limit depth.

Crouton Alpha

A colorful, readable sunset beach scene with playful subjects and a clear central reflection. Purposeful equipment and animal details reward inspection, and the principal attachments remain intact. Basic geometric anatomy, mixed viewpoints and sparse directional shadows limit its construction and depth; smooth gradients provide atmosphere with little material differentiation.

Score breakdown

CategoryClaude Fable 5.1Crouton Alpha
Task & likeness8.5/108.5/10
Anatomy & construction7.0/105.0/10
Space & placement7.0/105.5/10
Light & reflections7.0/105.5/10
Purposeful detail7.5/107.0/10
Artistry & character7.5/105.0/10
Materials & effects6.5/105.5/10
Visual integrity7.5/107.0/10

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 5.1

This benchmark has not been assessed yet.

Crouton Alpha

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 5.1

The raccoon rides on the dog's back, and the dog's extended foreleg reaches the jet ski controls. Expressive faces, a clear silhouette and sweeping spray make the action readable. Limb and handlebar overlaps weaken construction; broad shading provides limited volume, and the glowing sun has little corresponding reflection on the water. Clean vector shapes support an appealing but simplified illustration.

Crouton Alpha

A readable cartoon with expressive faces, purposeful markings and clear water motion. Hull shading and an underside shadow establish modest depth. The dog contacts the controls, but the raccoon's frontal pose leaves its seated weight unresolved. Simple anatomy and limited shared perspective constrain the drawing.

Score breakdown

CategoryClaude Fable 5.1Crouton Alpha
Task & likeness8.5/107.0/10
Anatomy & construction6.5/105.0/10
Space & placement7.0/106.0/10
Light & reflections5.5/106.0/10
Purposeful detail7.0/106.5/10
Artistry & character7.0/105.0/10
Materials & effects6.5/105.5/10
Visual integrity7.5/106.0/10

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 5.1

The pelican reads clearly, with an expressive face, prominent bill and appealing composition. Both legs connect to the body, but the far foot's pedal contact and the wing's steering grip remain unclear. Wheel alignment and background layers are coherent. Clean contours and feather lines give polish, while schematic machinery, limited surface texture and weak directional lighting constrain the finish.

Crouton Alpha

A recognizable, expressive pelican cyclist with purposeful feather and bicycle detail. Readable steering reach, connected machinery and modest body shading earn additional credit. Jointless legs, uncertain pedal engagement and unclear seated support keep the central action only partially resolved; shallow space and simple materials further limit the illustration.

Score breakdown

CategoryClaude Fable 5.1Crouton Alpha
Task & likeness8.5/107.0/10
Anatomy & construction7.0/105.0/10
Space & placement7.5/105.5/10
Light & reflections6.0/105.5/10
Purposeful detail7.0/106.5/10
Artistry & character7.0/105.5/10
Materials & effects6.0/105.0/10
Visual integrity8.0/106.0/10

Benchmark task

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