STEALTHMARK · HEAD TO HEAD

All comparisons ↗

Claude Fable 5.1 vs Iceman Contributor

Claude Fable 5.1 leads Iceman Contributor by 42.8 points on StealthMark, 62.0 to 19.2. It leads on all 9 benchmarks. 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

62.0/100Overall rank 8/53
19.2/100Overall rank 47/53

General Intelligence

58.9/100
11.7/100

Visual Intelligence

67.1/100
31.0/100

Reasoning efficiency

On every task, result quality and reasoning tokens are each compared with all measured models and weighed equally. Each dot is one model.

Single-step reasoning Result quality weighed against reasoning tokens on a single problem

Multi-step reasoning Result quality weighed against reasoning tokens across connected steps, as in agentic workflows

Open or local

BENCHMARK BY BENCHMARK

Where each model leads

  • Claude Fable 5.1
  • Iceman Contributor
  • Other models
  • Median

DATASHEET

Specs and pricing

Claude Fable 5.1 scores higher on StealthMark and runs 2.6× faster in our speed test.

  • Claude Fable 5.1
  • Iceman Contributor
  • Other models
  • Median
PricePer 1M output tokens, input below
Claude Fable 5.1: $50$10 inputIceman Contributor: No list price
Context windowTokens per request, max output below
Claude Fable 5.1: 1M128K max outputIceman Contributor: Not published
Output speedTokens per second, our measurement
Claude Fable 5.1: 1222.6× fastertokens/sIceman Contributor: 46tokens/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 37/472 of 3 levels

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

Iceman Contributor 3.2/100Rank 47/47

Survived 0 of 3
Foresight: complete playing field
Level 31 ptsTurn 7 / 20

Points per level

LevelClaude Fable 5.1Iceman Contributor
Level 1Second Thoughts
21 ptsOut of lives
0 ptsOut of lives
Level 2Pressure Pot
Pending
3 ptsOut of lives
Level 3Hide or Flight
8 ptsOut of lives
1 ptsOut of lives

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 80.2/100Rank 24/483 of 5 levels

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

Iceman Contributor 3.6/100Rank 44/48

Cleared 1 of 5
Latch: complete playing field
Level 55 ptsTurn 25 / 40

Points per level

LevelClaude Fable 5.1Iceman Contributor
Level 1Hold the door
Pending
5.2 ptsCleared
Level 2Crossfeed
9.8 ptsCleared
2.8 ptsFinished early
Level 3Relay vault
Pending
2.2 ptsFinished early
Level 4Passing bay
18.2 ptsClearedFinished early · 3 beacons left
4 ptsFinished early
Level 5Second thoughts
20.6 ptsCleared
5 ptsFinished early

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.

Iceman Contributor

The image provides limited evidence through rounded volume, faint wall strips and floor echoes. Its main sphere is small and low, the paint beads do not establish the required interaction history, and most of the defining mirror structure is missing.

Score breakdown

CategoryClaude Fable 5.1Iceman Contributor
State at 600 ms24.0/250.5/25
Camera and placement14.0/152.5/15
Reflections48.0/1207.5/120
Materials and scale7.5/103.0/10
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.

Iceman Contributor

The crystal crown, cyan eyes and blue faceting communicate an icy fantasy character. Anatomical readability is substantially weaker: the ringed torso, crowded facial construction and fingerless appendages do not resolve the requested childlike crouch or pouncing gesture. Sparse surface detail and shallow shading further limit the result.

Score breakdown

CategoryClaude Fable 5.1Iceman Contributor
Task & likeness6.5/104.0/10
Anatomy & construction7.0/103.0/10
Space & placement7.5/104.0/10
Light & reflections6.5/104.5/10
Purposeful detail6.0/104.0/10
Artistry & character7.0/104.5/10
Materials & effects6.5/104.5/10
Visual integrity8.0/104.0/10

Benchmark task

Claude Fable 5.1

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

Iceman Contributor

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

Mona Lisa

Different 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.

Iceman Contributor

The portrait retains a dark silhouette against an earthy landscape, but replication is weak. The frontal body, elongated facial proportions and undifferentiated hands lose the reference's defining pose and likeness. Basic gradients and layered hills provide some coherence, with little anatomical or painterly detail.

Score breakdown

CategoryClaude Fable 5.1Iceman Contributor
Task & likeness5.5/101.5/10
Anatomy & construction6.0/101.5/10
Space & placement6.0/102.5/10
Light & reflections6.0/102.0/10
Purposeful detail5.0/102.0/10
Artistry & character5.5/102.0/10
Materials & effects6.0/102.0/10
Visual integrity6.5/103.0/10

Benchmark task

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

Beach

Different 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.

Iceman Contributor

A coherent sunset beach with recognizable animals, playful details and effective palm framing. Connected silhouettes and layered scenery support modest construction and placement credit. Jointless figures, limited foreshortening and an inadequately separated sun and reflection keep the execution basic despite its attractive color.

Score breakdown

CategoryClaude Fable 5.1Iceman Contributor
Task & likeness8.5/107.0/10
Anatomy & construction7.0/103.5/10
Space & placement7.0/106.0/10
Light & reflections7.0/104.0/10
Purposeful detail7.5/105.5/10
Artistry & character7.5/103.5/10
Materials & effects6.5/104.5/10
Visual integrity7.5/105.0/10

Benchmark task

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

Ground Truth

Different task instructions

Physical reasoning, light and visual reconstruction.

The judgment

Claude Fable 5.1

This benchmark has not been assessed yet.

Iceman Contributor

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

Different 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.

Iceman Contributor

The sunset palette and red hull establish an appealing setting, but the central interaction remains unresolved. Overlapping bodies obscure the dog, supported seating is unclear, and no readable paw-to-control grip demonstrates steering. Simple construction, weak environmental lighting and loosely described spray limit depth and finish.

Score breakdown

CategoryClaude Fable 5.1Iceman Contributor
Task & likeness8.5/102.0/10
Anatomy & construction6.5/103.0/10
Space & placement7.0/103.0/10
Light & reflections5.5/104.0/10
Purposeful detail7.0/103.5/10
Artistry & character7.0/102.5/10
Materials & effects6.5/104.0/10
Visual integrity7.5/102.5/10

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

Different 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.

Iceman Contributor

A recognizable pelican and bicycle sit within an appealing sunset composition. Feather contours, bill shape and atmospheric colour provide character, but disconnected-looking leg origins, unclear pedal contact and unresolved steering weaken the central riding action. Consistent wheel alignment establishes a side view without resolving the rider's support.

Score breakdown

CategoryClaude Fable 5.1Iceman Contributor
Task & likeness8.5/104.0/10
Anatomy & construction7.0/103.5/10
Space & placement7.5/103.5/10
Light & reflections6.0/105.0/10
Purposeful detail7.0/104.5/10
Artistry & character7.0/103.5/10
Materials & effects6.0/104.0/10
Visual integrity8.0/103.0/10

Benchmark task

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