STEALTHMARK · HEAD TO HEAD

All comparisons ↗

Claude Fable 5.1 vs Gemini 4 Argon

Gemini 4 Argon leads Claude Fable 5.1 by 5.4 points on StealthMark, 67.4 to 62.0. It leads on all 9 benchmarks. Gemini 4 Argon scores higher on Raccoon, with its largest category advantage in anatomy & construction.

See the difference ↘
All results ↗
All results ↗

Overall StealthMark

62.0/100Overall rank 8/53
67.4/100Overall rank 5/53

General Intelligence

58.9/100
63.6/100

Visual Intelligence

67.1/100
74.4/100

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

BENCHMARK BY BENCHMARK

Where each model leads

  • Claude Fable 5.1
  • Gemini 4 Argon
  • Other models
  • Median

DATASHEET

Specs and pricing

Gemini 4 Argon scores higher on StealthMark, is 5× cheaper per output token and runs 18% faster in our speed test. Both take about 1M tokens of context.

  • Claude Fable 5.1
  • Gemini 4 Argon
  • Other models
  • Median
PricePer 1M output tokens, input below
Claude Fable 5.1: $50$10 inputGemini 4 Argon: $105× cheaper$2 input
Context windowTokens per request, max output below
Claude Fable 5.1: 1MTied128K max outputGemini 4 Argon: 1MTied1M max output
Output speedTokens per second, our measurement
Claude Fable 5.1: 122tokens/sGemini 4 Argon: 14418% fastertokens/s
Developer
AnthropicGoogle
Released
1 Sep 202613 Oct 2026
Origin
United StatesBoth
Input → output
Text, image → textText, image, audio, video, PDF → text
Architecture
Not publishedSparse mixture-of-experts (MoE) transformer with native multimodal inputs

Full datasheets, every price and sourceClaude Fable 5.1 ↗Gemini 4 Argon ↗

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

Gemini 4 Argon 48.6/100Rank 19/47

Survived 1 of 3
Foresight: complete playing field
Level 36 ptsTurn 7 / 20

Points per level

LevelClaude Fable 5.1Gemini 4 Argon
Level 1Second Thoughts
21 ptsOut of lives
26 ptsSurvived
Level 2Pressure Pot
Pending
9 ptsOut of lives
Level 3Hide or Flight
8 ptsOut of lives
6 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

Gemini 4 Argon 82.6/100Rank 6/48

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

Points per level

LevelClaude Fable 5.1Gemini 4 Argon
Level 1Hold the door
Pending
5.2 ptsCleared
Level 2Crossfeed
9.8 ptsCleared
9.8 ptsCleared
Level 3Relay vault
Pending
19.2 ptsCleared
Level 4Passing bay
18.2 ptsClearedFinished early · 3 beacons left
18.2 ptsClearedFinished early · 3 beacons left
Level 5Second thoughts
20.6 ptsCleared
20.6 ptsCleared

Newton's Mirror

Same task instructions

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

The judgment

Claude Fable 5.1

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.

Gemini 4 Argon

The central sphere, separate airborne black blob, flattened cyan contact and displaced crimson aftermath support the principal camera and physical-state requirements. Open lateral lanes and initial reflection placements provide partial optical structure, but missing outer chains, sparse nested imagery and incomplete emitter mappings remain substantial limitations. The raised crimson mass also weakens paint-scale fidelity.

Score breakdown

CategoryClaude Fable 5.1Gemini 4 Argon
State at 600 ms24.0/2524.5/25
Camera and placement14.0/1514.5/15
Reflections48.0/12050.5/120
Materials and scale7.5/108.5/10
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.

Gemini 4 Argon

An appealing, controlled illustration with a distinctive buoyant silhouette, expressive comic face and rich luminous colour. The full composition and grounded slipper read clearly. The principal limitation is the crowded raised-foot interaction: paws, toes and lining overlap without making the bent leg or tight fit unmistakable.

Score breakdown

CategoryClaude Fable 5.1Gemini 4 Argon
Task & likeness6.5/107.0/10
Anatomy & construction7.0/106.5/10
Space & placement7.5/107.5/10
Light & reflections6.5/107.5/10
Purposeful detail6.0/108.0/10
Artistry & character7.0/107.0/10
Materials & effects6.5/107.0/10
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.

Gemini 4 Argon

A luminous little dragon struggles with its bedtime slippers while a buoyant tail pulls it upward. The scene tests expressive anatomy, physical contact and the contrast between translucent forms and heavy objects.

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.

Gemini 4 Argon

A coherent, moderately complex Mona Lisa reconstruction with substantial portrait volume, articulated clothing and landscape recession. Specific source features support replication beyond recognition alone. Altered facial likeness, uncertain crossed-hand anatomy and pervasive colored crackle keep the result uneven despite its developed shading and detail.

Score breakdown

CategoryClaude Fable 5.1Gemini 4 Argon
Task & likeness5.5/106.5/10
Anatomy & construction6.0/106.5/10
Space & placement6.0/106.5/10
Light & reflections6.0/107.0/10
Purposeful detail5.0/106.0/10
Artistry & character5.5/106.5/10
Materials & effects6.0/107.0/10
Visual integrity6.5/107.0/10

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 5.1

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.

Gemini 4 Argon

A strong decorative beach illustration with controlled color, intricate silhouettes and abundant playful detail. Connected dolphin forms and recognizable equipment support its construction, while the aligned sunset reflection anchors the scene. Compressed wave depth, ambiguous foreground support and uneven reflection specificity limit physical coherence. The saved comparisons support retaining the category assessments.

Score breakdown

CategoryClaude Fable 5.1Gemini 4 Argon
Task & likeness8.5/109.0/10
Anatomy & construction7.0/107.5/10
Space & placement7.0/108.5/10
Light & reflections7.0/108.5/10
Purposeful detail7.5/109.0/10
Artistry & character7.5/108.0/10
Materials & effects6.5/108.0/10
Visual integrity7.5/108.0/10

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 5.1

This benchmark has not been assessed yet.

Gemini 4 Argon

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.

Gemini 4 Argon

An accomplished illustration with expressive characters, intricate spray and strong depth. Direct back seating, steering connections and hull-water contact are only partly demonstrated. Clean graphic execution and purposeful detail remain strengths, while shadows and reflections provide limited physical grounding.

Score breakdown

CategoryClaude Fable 5.1Gemini 4 Argon
Task & likeness8.5/108.5/10
Anatomy & construction6.5/108.0/10
Space & placement7.0/107.5/10
Light & reflections5.5/107.5/10
Purposeful detail7.0/108.5/10
Artistry & character7.0/108.5/10
Materials & effects6.5/108.0/10
Visual integrity7.5/108.0/10

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 5.1

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.

Gemini 4 Argon

An expressive, detailed illustration with controlled gradients and coherent environmental depth. Continuous body contours and connected bicycle components establish competent construction. Steering grip and pedal engagement remain less explicit than the decorative details and wheel placement. These contact uncertainties limit action and placement credit without establishing broken anatomy.

Score breakdown

CategoryClaude Fable 5.1Gemini 4 Argon
Task & likeness8.5/109.0/10
Anatomy & construction7.0/108.5/10
Space & placement7.5/108.0/10
Light & reflections6.0/108.0/10
Purposeful detail7.0/108.5/10
Artistry & character7.0/108.5/10
Materials & effects6.0/108.5/10
Visual integrity8.0/108.5/10

Benchmark task

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