STEALTHMARK · HEAD TO HEAD

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Claude Sonnet 5.5 vs GPT-6 Astra

GPT-6 Astra scores 6.0 points higher overall (68.7 vs 62.7). GPT-6 Astra scores higher on Newton's Mirror, with its largest category advantage in reflections.

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Overall StealthMark

62.7/100
68.7/100

General Intelligence

45.2/100
59.0/100

Visual Intelligence

76.1/100
76.1/100

Newton's Mirror

Same prompt

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

Claude Sonnet 5.540.8/100

Claude Sonnet 5.5: Newton's Mirror SVG benchmark
Researcher observations

The near-field silhouettes, broad perspective and paint contact order are recognizable. Missing outer chains, truncated repetitions and absent ordered imagery within the main and reflected spheres substantially limit the reflection system. Sparse spherical highlights leave much of the curved room and emitter mapping unsupported, despite some plausible planar light sequences.

Prompt withheld

This prompt is held back to prevent benchmaxxing.

GPT-6 Astra57.8/100

GPT-6 Astra: Newton's Mirror SVG benchmark
Researcher observations

Major placement and the visible contact sequence are convincing. Dense planar light repetition, recognizable spherical panel images and simplified nested sphere motifs provide useful optical structure. Missing outer chains, truncated distant sequences and incorrect bead-like belts still leave the recursive reflections substantially incomplete.

Prompt withheld

This prompt is held back to prevent benchmaxxing.

Compare category scores
CategoryClaude Sonnet 5.5GPT-6 Astra
State at 600 ms25.0/2525.0/25
Camera and placement15.0/1515.0/15
Reflections23.5/12054.0/120
Materials and scale10.0/1010.0/10
Floor-damage reward0.0/100.0/10

Selfie

Different prompts

Claude Sonnet 5.579.0/100

Claude Sonnet 5.5: Selfie SVG benchmark
Researcher observations

The centered coral squid has a friendly, composed expression and a balanced flower-like silhouette. Eight thick arms and two slender tentacles remain visibly connected, with no inverted parts. The mantle is elongated rather than compact, and the arm spacing is uneven. Soft shading gives volume, but dense stippling weakens the requested smooth matte finish; the broad background halo makes depth less precise.

Prompt withheld

This prompt is held back to prevent benchmaxxing.

GPT-6 Astra76.0/100

GPT-6 Astra: Selfie SVG benchmark
Researcher observations

The sixfold silhouette, pale coloring, outward heads and central hexagon closely match the brief. Fine scales and soft shading support rounded volume. However, several crossings have conspicuous rectangular seams and weak contact shadows, making the weave feel assembled. Small heads have limited anatomical definition, and the repetitive texture conveys less organic life than requested.

Prompt withheld

This prompt is held back to prevent benchmaxxing.

Compare category scores
CategoryClaude Sonnet 5.5GPT-6 Astra
Prompt & likeness8.0/108.5/10
Anatomy & construction8.0/107.5/10
Space & placement8.0/107.5/10
Light & reflections7.5/107.0/10
Purposeful detail7.5/107.5/10
Artistry & character8.0/108.0/10
Materials & effects7.0/107.0/10
Visual integrity8.5/107.0/10

Beach

Same prompt

Claude Sonnet 5.582.3/100

Claude Sonnet 5.5: Beach SVG benchmark
Researcher observations

A richly designed beach illustration combines radiant sunset bands, intricate palm fans and playful silhouettes within a cohesive purple, coral and turquoise palette. Carefully varied accessories reward close inspection, while overlapping foreground forms and shoreline layers organize the abundant activity. Dense palm strokes compete with focal subjects; animal anatomy, relative scales and reflected silhouettes remain simplified.

Exact prompt

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

GPT-6 Astra76.8/100

GPT-6 Astra: Beach SVG benchmark
Researcher observations

A coherent sunset beach illustration with an inviting palette, strong palm framing and a clear sun reflection. Animals, playing figures and beach equipment provide variety. Simplified human and dog anatomy, weak dolphin splash cues and uneven shadow directions limit physical conviction. Clean silhouettes and small decorative details support an appealing, polished composition.

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 Sonnet 5.5GPT-6 Astra
Prompt & likeness9.0/108.5/10
Anatomy & construction7.0/107.0/10
Space & placement8.5/107.5/10
Light & reflections7.5/107.5/10
Purposeful detail9.0/107.5/10
Artistry & character9.5/108.0/10
Materials & effects7.5/107.5/10
Visual integrity7.5/108.0/10

Mona Lisa

Different prompts

Claude Sonnet 5.563.8/100

Claude Sonnet 5.5: Mona Lisa SVG benchmark
Researcher observations

The crossed hands, dark dress, restrained smile and winding landscape clearly recall the Mona Lisa. Replication is limited by the frontal symmetry, wide eyes, elongated neck and flattened fingers. Soft facial shading provides volume, but heavy darkness and pervasive crackle obscure forms. The composition is coherent; the landscape and fabric remain visibly schematic.

Exact prompt

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

GPT-6 Astra67.3/100

GPT-6 Astra: Mona Lisa SVG benchmark
Researcher observations

The crossed hands, restrained smile, dark clothing and hazy landscape clearly recall the Mona Lisa. Replication is limited by the frontal, elongated face, schematic eyes and stiff fingers. Soft shading gives basic volume, but broad garment shapes and angular scenery lack the original’s nuanced depth and painterly transitions. The frame and composition are controlled; surface grain adds texture without resolving the simplified drawing.

Exact prompt

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

Compare category scores
CategoryClaude Sonnet 5.5GPT-6 Astra
Prompt & likeness7.0/107.0/10
Anatomy & construction6.0/106.0/10
Space & placement6.5/106.5/10
Light & reflections6.5/107.0/10
Purposeful detail6.0/106.5/10
Artistry & character6.5/107.0/10
Materials & effects5.5/107.0/10
Visual integrity6.5/107.5/10

Raccoon

Same prompt

Claude Sonnet 5.576.3/100

Claude Sonnet 5.5: Raccoon SVG benchmark
Researcher observations

The raccoon clearly rides on the dog's back while the dog grips the jet ski controls. Expressive faces, vivid colors and a sweeping wake make the scene appealing. Visible limbs connect coherently, but overlapping steering paws and an indistinct control mounting weaken construction. Flat character lighting and simplified water limit depth and material realism.

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-6 Astra79.5/100

GPT-6 Astra: Raccoon SVG benchmark
Researcher observations

Expressive animals, a balanced sunset composition and sweeping wake make an appealing illustration. The raccoon rides the dog's back, and the dog's connected foreleg reaches the controls. The compact steering assembly and layered paws are less clearly constructed. Lighting remains mostly flat, with little shadow or sun reflection. Clean contours and purposeful details support strong illustrative execution.

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 Sonnet 5.5GPT-6 Astra
Prompt & likeness8.5/108.5/10
Anatomy & construction7.0/107.5/10
Space & placement7.5/108.0/10
Light & reflections6.5/106.5/10
Purposeful detail8.0/108.0/10
Artistry & character8.0/108.5/10
Materials & effects7.5/108.0/10
Visual integrity8.0/108.5/10

Pelican

Benchmax control

Outside General and Visual Intelligence.

Claude Sonnet 5.576.8/100

Claude Sonnet 5.5: Pelican SVG benchmark
Researcher observations

The pelican is immediately recognizable, with an expressive face, generous bill and appealing cycling pose. Spokes, chain, feathers and scarf provide purposeful detail. The bicycle largely holds together, though overlapping angular legs obscure the far foot’s pedal contact. Clean outlines and balanced composition succeed; flat surfaces and limited directional lighting constrain depth.

Exact prompt

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

GPT-6 Astra75.8/100

GPT-6 Astra: Pelican SVG benchmark
Researcher observations

The pelican's long bill, flowing scarf and warm coastal palette create a charming, balanced illustration. Wheels, spokes and frame are largely coherent, but neither wing reaches the handlebars, and the rear leg's pedal contact is unclear. Flat lighting and simplified surfaces limit depth despite clean outlines and attractive feather detail.

Exact prompt

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

Compare category scores
CategoryClaude Sonnet 5.5GPT-6 Astra
Prompt & likeness9.0/108.0/10
Anatomy & construction7.5/106.5/10
Space & placement7.5/107.5/10
Light & reflections6.5/107.0/10
Purposeful detail8.0/108.0/10
Artistry & character7.5/108.5/10
Materials & effects6.5/107.5/10
Visual integrity8.0/108.0/10