STEALTHMARK · HEAD TO HEAD

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Claude Opus 5.5 vs GPT 5.6 Luna

Claude Opus 5.5 scores 17.3 points higher overall (66.0 vs 48.7). Claude Opus 5.5 scores higher on Newton's Mirror, with its largest category advantage in reflections.

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Overall StealthMark

66.0/100
48.7/100

General Intelligence

55.3/100
24.0/100

Visual Intelligence

74.5/100
67.1/100

Newton's Mirror

Same prompt

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

Claude Opus 5.552.5/100

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

Open lateral sightlines, first reflected silhouettes and near-field planar panel placement are convincing. Missing outer chains, truncated repetitions and absent nested spherical room and emitter imagery remain the main weaknesses.

Prompt withheld

This prompt is held back to prevent benchmaxxing.

GPT 5.6 Luna18.1/100

GPT 5.6 Luna: Newton's Mirror SVG benchmark
Researcher observations

The room enclosure has coherent symmetric perspective, with the overhead panel, sphere and black aligned centrally. The sphere and airborne black occupy substantially lower positions than the reference framing, inconsistent with the prescribed camera aim. The diagonal crimson streak does not establish the required surface transport. Faint wall sphere images provide limited mirrored correspondence, but the shallow floor image, missing receding chains, absent nested sphere imagery and sparse emitter mapping leave most reflection structure unsupported.

Prompt withheld

This prompt is held back to prevent benchmaxxing.

Compare category scores
CategoryClaude Opus 5.5GPT 5.6 Luna
State at 600 ms25.0/2515.0/25
Camera and placement15.0/154.0/15
Reflections46.5/1203.5/120
Materials and scale8.0/1010.0/10
Floor-damage reward0.0/100.0/10

Selfie

Different prompts

Claude Opus 5.578.3/100

Claude Opus 5.5: Selfie SVG benchmark
Researcher observations

The centered coral squid has a friendly, restrained expression and a balanced radial silhouette within a cream arch. Smooth curves and soft shading give it an appealing matte finish. The mantle is more elongated than compact, the upper arms are visually ambiguous, and the two hanging tentacles read somewhat like legs. Clean execution supports a strong stylized illustration.

Prompt withheld

This prompt is held back to prevent benchmaxxing.

GPT 5.6 Luna61.8/100

GPT 5.6 Luna: Selfie SVG benchmark
Researcher observations

Six pale, outward-facing heads and six rounded lobes make the knot recognizable. The central hexagonal opening remains clear. However, broad gray crossing panels flatten the weave, several inner joins resemble capped strips, and sparse oversized scale marks leave the bodies looking more like decorated ribbons than living snakes.

Prompt withheld

This prompt is held back to prevent benchmaxxing.

Compare category scores
CategoryClaude Opus 5.5GPT 5.6 Luna
Prompt & likeness8.0/107.5/10
Anatomy & construction7.5/106.0/10
Space & placement8.0/106.5/10
Light & reflections7.5/105.0/10
Purposeful detail7.5/105.5/10
Artistry & character8.0/106.5/10
Materials & effects7.5/105.0/10
Visual integrity8.5/106.0/10

Beach

Same prompt

Claude Opus 5.578.0/100

Claude Opus 5.5: Beach SVG benchmark
Researcher observations

A lively, well-composed beach illustration with rich sunset colors, recognizable animals and appealing accessories. The sun reflection establishes a strong central focus. Clean silhouettes and small details reward inspection, though simplified animal construction, uneven contact shadows and mostly flat materials limit depth and realism.

Exact prompt

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

GPT 5.6 Luna67.8/100

GPT 5.6 Luna: Beach SVG benchmark
Researcher observations

The warm sunset, palm silhouette and varied beach activities create an appealing, readable composition. Animals, birds and a broad sun reflection satisfy the brief. Drawing remains elementary: angular airborne sea animals lack splash or convincing motion, the crab's claws are awkwardly constructed, and repeated reflection bands suggest a stepped platform. Clean outlines and pleasant colors exceed the anatomical and spatial sophistication.

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 Opus 5.5GPT 5.6 Luna
Prompt & likeness8.5/108.0/10
Anatomy & construction7.5/106.0/10
Space & placement7.0/106.5/10
Light & reflections8.0/106.5/10
Purposeful detail8.0/106.5/10
Artistry & character8.0/107.0/10
Materials & effects6.5/106.0/10
Visual integrity8.5/107.5/10

Mona Lisa

Same prompt

Claude Opus 5.564.8/100

Claude Opus 5.5: Mona Lisa SVG benchmark
Researcher observations

The portrait preserves the recognizable composition, dark veil, folded hands and distant landscape. Replication is limited by the elongated face and neck, conspicuous eyes and simplified smile. Hands remain connected but their rounded fingers and wrists lack convincing anatomy. Restrained colors create cohesion; shallow modeling and pervasive mottling weaken volume and painterly subtlety.

Exact prompt

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

GPT 5.6 Luna63.0/100

GPT 5.6 Luna: Mona Lisa SVG benchmark
Researcher observations

The central portrait, dark clothing, crossed hands and muted landscape clearly evoke Mona Lisa. Replication is limited by the elongated face, conspicuous eyes and simplified smile. Overlapping fingers have uncertain anatomy, while broad gradients and heavy outlines flatten the portrait. The composition and restrained palette remain coherent.

Exact prompt

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

Compare category scores
CategoryClaude Opus 5.5GPT 5.6 Luna
Prompt & likeness7.0/106.5/10
Anatomy & construction6.0/106.0/10
Space & placement6.5/106.5/10
Light & reflections6.0/106.5/10
Purposeful detail6.5/105.5/10
Artistry & character6.5/106.5/10
Materials & effects6.5/105.5/10
Visual integrity7.0/107.0/10

Raccoon

Same prompt

Claude Opus 5.575.0/100

Claude Opus 5.5: Raccoon SVG benchmark
Researcher observations

The masked raccoon clearly rides the dog's back, and the dog's forward paw reaches the steering grip. Expressive faces, vivid colors and sweeping wakes create an appealing illustration. Connected limbs remain schematic, as does the small steering assembly. The broad hull and flat foam weaken water contact; the glowing sun lacks a corresponding reflection or convincing cast shadows.

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 5.6 Luna70.8/100

GPT 5.6 Luna: Raccoon SVG benchmark
Researcher observations

Expressive animals, a striped tail and clean outlines make the scene appealing and readable. The raccoon sits convincingly on the dog's back, but the overlapping steering paws are ambiguous and the control stem stops above the hull. Broad wake shapes suggest motion; the glowing sun lacks a corresponding water reflection.

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 Opus 5.5GPT 5.6 Luna
Prompt & likeness8.5/107.5/10
Anatomy & construction7.0/106.5/10
Space & placement7.5/107.0/10
Light & reflections6.0/106.0/10
Purposeful detail7.5/107.5/10
Artistry & character8.0/107.5/10
Materials & effects7.0/106.5/10
Visual integrity8.0/108.0/10

Pelican

Benchmax control

Outside General and Visual Intelligence.

Claude Opus 5.572.5/100

Claude Opus 5.5: Pelican SVG benchmark
Researcher observations

The recognizable pelican, orderly bicycle wheels and harmonious sunset create an appealing illustration. Both legs connect to the body and reach pedals; no clear detached or inverted parts appear. Steering contact and seating support are less convincing, while the drivetrain remains schematic. Crisp outlines give a clean finish, but limited shading and flat surfaces leave the scene with modest depth.

Exact prompt

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

GPT 5.6 Luna76.0/100

GPT 5.6 Luna: Pelican SVG benchmark
Researcher observations

A recognizable pelican cyclist with an expressive profile, balanced composition and controlled outlines. Head, neck and torso connect coherently. The bicycle wheels and frame are convincing, but overlapping feet obscure pedal contact, the drivetrain lacks a clear chain, and the wing's handlebar grip is schematic. Atmospheric color succeeds more strongly than directional lighting or material depth.

Exact prompt

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

Compare category scores
CategoryClaude Opus 5.5GPT 5.6 Luna
Prompt & likeness8.5/108.5/10
Anatomy & construction6.5/107.0/10
Space & placement7.0/107.5/10
Light & reflections6.0/106.5/10
Purposeful detail7.5/107.5/10
Artistry & character7.5/108.0/10
Materials & effects6.0/107.0/10
Visual integrity8.5/108.5/10