STEALTHMARK · HEAD TO HEAD

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GPT 5.5 vs GPT 5.6 Luna

GPT 5.6 Luna scores 6.7 points higher overall (48.7 vs 42.0). GPT 5.5 leads General Intelligence; GPT 5.6 Luna leads Visual Intelligence. GPT 5.6 Luna scores higher on Selfie, with its largest category advantage in prompt & likeness.

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All results ↗

Overall StealthMark

42.0/100
48.7/100

General Intelligence

26.2/100
24.0/100

Visual Intelligence

53.4/100
67.1/100

Newton's Mirror

Same prompt

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

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.

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
CategoryGPT 5.5GPT 5.6 Luna
State at 600 ms19.5/2515.0/25
Camera and placement7.0/154.0/15
Reflections5.0/1203.5/120
Materials and scale6.0/1010.0/10
Floor-damage reward0.0/100.0/10

Selfie

Same prompt

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.

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
CategoryGPT 5.5GPT 5.6 Luna
Prompt & likeness2.5/107.5/10
Anatomy & construction3.0/106.0/10
Space & placement5.0/106.5/10
Light & reflections5.0/105.0/10
Purposeful detail4.5/105.5/10
Artistry & character4.5/106.5/10
Materials & effects4.5/105.0/10
Visual integrity7.0/106.0/10

Beach

Same prompt

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

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
CategoryGPT 5.5GPT 5.6 Luna
Prompt & likeness8.0/108.0/10
Anatomy & construction5.5/106.0/10
Space & placement6.0/106.5/10
Light & reflections6.0/106.5/10
Purposeful detail5.0/106.5/10
Artistry & character6.5/107.0/10
Materials & effects5.0/106.0/10
Visual integrity8.0/107.5/10

Mona Lisa

Same prompt

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

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
CategoryGPT 5.5GPT 5.6 Luna
Prompt & likeness6.0/106.5/10
Anatomy & construction4.5/106.0/10
Space & placement5.5/106.5/10
Light & reflections5.0/106.5/10
Purposeful detail3.5/105.5/10
Artistry & character5.5/106.5/10
Materials & effects4.0/105.5/10
Visual integrity7.5/107.0/10

Raccoon

Same prompt

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

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
CategoryGPT 5.5GPT 5.6 Luna
Prompt & likeness6.0/107.5/10
Anatomy & construction4.0/106.5/10
Space & placement6.0/107.0/10
Light & reflections5.5/106.0/10
Purposeful detail5.5/107.5/10
Artistry & character6.5/107.5/10
Materials & effects5.5/106.5/10
Visual integrity6.5/108.0/10

Pelican

Benchmax control

Outside General and Visual Intelligence.

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

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
CategoryGPT 5.5GPT 5.6 Luna
Prompt & likeness7.5/108.5/10
Anatomy & construction4.5/107.0/10
Space & placement6.5/107.5/10
Light & reflections6.5/106.5/10
Purposeful detail6.0/107.5/10
Artistry & character7.5/108.0/10
Materials & effects6.0/107.0/10
Visual integrity7.5/108.5/10