STEALTHMARK · HEAD TO HEAD

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Claude Fable 5.1 vs GPT 5.5

Claude Fable 5.1 scores 20.1 points higher overall (62.1 vs 42.0). Claude Fable 5.1 scores higher on Newton's Mirror, with its largest category advantage in reflections.

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Overall StealthMark

62.1/100
42.0/100

General Intelligence

54.3/100
26.2/100

Visual Intelligence

67.7/100
53.4/100

Newton's Mirror

Same prompt

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

Claude Fable 5.151.7/100

Claude Fable 5.1: Newton's Mirror SVG benchmark
Researcher observations

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.

Prompt withheld

This prompt is held back to prevent benchmaxxing.

GPT 5.520.8/100

GPT 5.5: Newton's Mirror SVG benchmark
Researcher observations

The paint ordering and separate black bead support part of the physical state, but adhesion and rotational transport remain only partly established. The sweeping cyan arc and long crimson lobes do not clearly communicate the limited time since their respective impacts. The main sphere is too large and too low, and the black bead is below its required projected position. Displaced isolated sphere images, a flattened floor echo and missing recursive, nested and emitter reflections provide little coherent optical structure. The colored paint is excessively bulky for the specified quantities.

Prompt withheld

This prompt is held back to prevent benchmaxxing.

Compare category scores
CategoryClaude Fable 5.1GPT 5.5
State at 600 ms24.0/2519.5/25
Camera and placement14.0/157.0/15
Reflections48.0/1205.0/120
Materials and scale7.0/106.0/10
Floor-damage reward0.0/100.0/10

Selfie

Different prompts

Claude Fable 5.169.0/100

Claude Fable 5.1: Selfie SVG benchmark
Researcher observations

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.

Prompt withheld

This prompt is held back to prevent benchmaxxing.

GPT 5.542.8/100

GPT 5.5: Selfie SVG benchmark
Researcher observations

Six pale, scaled lobes form a balanced radial arrangement, but they remain separate capsules rather than an interlocking serpent knot. There are no crossings, alternating overlaps, or crisp inner bends; the central hexagon is an isolated outline. Small outward-facing heads sit within the lobes without integrated necks. Soft shading and tidy contours provide some finish, while repetitive oval scales and cartoon faces limit organic credibility.

Prompt withheld

This prompt is held back to prevent benchmaxxing.

Compare category scores
CategoryClaude Fable 5.1GPT 5.5
Prompt & likeness6.5/102.5/10
Anatomy & construction6.5/103.0/10
Space & placement7.5/105.0/10
Light & reflections6.5/105.0/10
Purposeful detail6.0/104.5/10
Artistry & character7.5/104.5/10
Materials & effects6.5/104.5/10
Visual integrity8.0/107.0/10

Beach

Same prompt

Claude Fable 5.175.0/100

Claude Fable 5.1: Beach SVG benchmark
Researcher observations

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.

Exact prompt

Create an SVG of a amazing beach scene. Sunset, animals, fun, birds, reflections Make it a masterpiece, no tools allowed

GPT 5.563.3/100

GPT 5.5: Beach SVG benchmark
Researcher observations

The sunset, palms, birds, playful animals and ball clearly establish the requested beach scene. Warm sky gradients and clean silhouettes make it appealing. Animal construction remains basic, especially the round-eared foreground figure's unclear torso and limbs. The dolphin lacks a convincing splash, and broad reflection bands suggest sunset light without resolving its behavior on water.

Exact prompt

Create an SVG of a amazing beach scene. Sunset, animals, fun, birds, reflections Make it a masterpiece, no tools allowed

Compare category scores
CategoryClaude Fable 5.1GPT 5.5
Prompt & likeness8.5/108.0/10
Anatomy & construction7.0/105.5/10
Space & placement7.0/106.0/10
Light & reflections7.0/106.0/10
Purposeful detail7.5/105.0/10
Artistry & character8.0/106.5/10
Materials & effects6.5/105.0/10
Visual integrity8.0/108.0/10

Mona Lisa

Same prompt

Claude Fable 5.156.5/100

Claude Fable 5.1: Mona Lisa SVG benchmark
Researcher observations

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.

Exact prompt

Replicate mona-lisa as SVG Make it a masterpiece, no tools allowed

GPT 5.552.5/100

GPT 5.5: Mona Lisa SVG benchmark
Researcher observations

The dark veil, restrained smile, crossed hands and muted landscape establish Mona Lisa references. Replication is limited by the oversized frontal face, simplified eyes and hands drawn as overlapping tapered shapes without fingers. Clean contours and a balanced frame support the composition, but broad landscape bands, sparse garment detail and shallow shading leave the portrait basic rather than masterful.

Exact prompt

Replicate mona-lisa as SVG Make it a masterpiece, no tools allowed

Compare category scores
CategoryClaude Fable 5.1GPT 5.5
Prompt & likeness6.0/106.0/10
Anatomy & construction5.0/104.5/10
Space & placement6.0/105.5/10
Light & reflections6.0/105.0/10
Purposeful detail5.0/103.5/10
Artistry & character5.5/105.5/10
Materials & effects5.5/104.0/10
Visual integrity6.5/107.5/10

Raccoon

Same prompt

Claude Fable 5.170.8/100

Claude Fable 5.1: Raccoon SVG benchmark
Researcher observations

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.

Exact prompt

Generate an SVG: A raccoon sits on a dog's back while the dog steers a jet ski Make it a masterpiece, no tools allowed

GPT 5.556.0/100

GPT 5.5: Raccoon SVG benchmark
Researcher observations

The raccoon's masked face, bright hull and sweeping wake make the scene readable and lively. The dog is much less resolved: its head is ambiguous, overlapping brown forms obscure its anatomy, and its paws do not visibly grip the controls. Smooth shapes and cheerful colors provide appeal, but weak steering construction and limited depth keep the drawing uneven.

Exact prompt

Generate an SVG: A raccoon sits on a dog's back while the dog steers a jet ski Make it a masterpiece, no tools allowed

Compare category scores
CategoryClaude Fable 5.1GPT 5.5
Prompt & likeness8.5/106.0/10
Anatomy & construction6.5/104.0/10
Space & placement7.0/106.0/10
Light & reflections5.5/105.5/10
Purposeful detail7.0/105.5/10
Artistry & character7.5/106.5/10
Materials & effects6.5/105.5/10
Visual integrity7.5/106.5/10

Pelican

Benchmax control

Outside General and Visual Intelligence.

Claude Fable 5.172.3/100

Claude Fable 5.1: Pelican SVG benchmark
Researcher observations

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.

Exact prompt

Generate an SVG of a pelican riding a bicycle Make it a masterpiece, no tools allowed

GPT 5.564.3/100

GPT 5.5: Pelican SVG benchmark
Researcher observations

The oversized bill, bright bicycle and sunset create an appealing, recognizable cartoon. Riding mechanics are less convincing: the wing has no clear steering contact, leg attachments are uneven, and feet do not visibly engage pedals. A dark notch complicates the rear neck junction. Clean contours and orderly spokes provide polish, while simplified anatomy and lighting limit depth.

Exact prompt

Generate an SVG of a pelican riding a bicycle Make it a masterpiece, no tools allowed

Compare category scores
CategoryClaude Fable 5.1GPT 5.5
Prompt & likeness8.5/107.5/10
Anatomy & construction6.5/104.5/10
Space & placement7.5/106.5/10
Light & reflections6.0/106.5/10
Purposeful detail7.0/106.0/10
Artistry & character7.5/107.5/10
Materials & effects6.0/106.0/10
Visual integrity8.0/107.5/10