STEALTHMARK · HEAD TO HEAD

All comparisons ↗

Claude Opus 5.5 vs GPT 5.6 Terra

Claude Opus 5.5 scores 14.9 points higher overall (66.0 vs 51.1). Claude Opus 5.5 scores higher on Newton's Mirror, with its largest category advantage in reflections.

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All results ↗

Overall StealthMark

66.0/100
51.1/100

General Intelligence

55.3/100
31.1/100

Visual Intelligence

74.5/100
66.2/100

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 Terra23.3/100

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

The real sphere and airborne black blob are substantially too low in the complete frame after accounting for aspect ratio. The first wall and floor reflections have incompatible placement, relative size or silhouette. Both lateral regions lack the references' receding lane-and-chain organization. The few recognizable mirror images provide limited optical structure. The main, side and floor spheres replace nested mirror imagery with smooth bands, while sparse planar light patches and broad spherical highlights fail to establish coherent repeated emitter mapping.

Prompt withheld

This prompt is held back to prevent benchmaxxing.

Compare category scores
CategoryClaude Opus 5.5GPT 5.6 Terra
State at 600 ms25.0/2523.5/25
Camera and placement15.0/156.0/15
Reflections46.5/1207.0/120
Materials and scale8.0/105.5/10
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 Terra73.0/100

GPT 5.6 Terra: Selfie SVG benchmark
Researcher observations

Six ivory heads and rounded lobes create a striking radial emblem around a clear hexagonal opening. Soft shading gives the bodies volume, but abrupt rectangular and diagonal band endings make the continuous alternating weave ambiguous. Repetitive scale lines and simplified faces convey an ornamental serpent more convincingly than living anatomy.

Prompt withheld

This prompt is held back to prevent benchmaxxing.

Compare category scores
CategoryClaude Opus 5.5GPT 5.6 Terra
Prompt & likeness8.0/107.5/10
Anatomy & construction7.5/106.5/10
Space & placement8.0/107.5/10
Light & reflections7.5/107.5/10
Purposeful detail7.5/107.0/10
Artistry & character8.0/108.0/10
Materials & effects7.5/107.0/10
Visual integrity8.5/107.5/10

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 Terra73.3/100

GPT 5.6 Terra: Beach SVG benchmark
Researcher observations

Warm sunset gradients, framing palms and colorful beach activities create an appealing scene. Animals, birds and a sun reflection fulfill the brief. The dog and turtle remain schematic, foreground depth is shallow, and the reflection forms rigid bands. Clean silhouettes and readable accessories support a competent illustration, but limited anatomy, material variation and lighting keep it below exceptional.

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 Terra
Prompt & likeness8.5/108.5/10
Anatomy & construction7.5/107.0/10
Space & placement7.0/107.0/10
Light & reflections8.0/106.5/10
Purposeful detail8.0/107.0/10
Artistry & character8.0/107.5/10
Materials & effects6.5/106.5/10
Visual integrity8.5/108.0/10

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 Terra49.5/100

GPT 5.6 Terra: Mona Lisa SVG benchmark
Researcher observations

The dark clothing, central portrait and restrained smile evoke the Mona Lisa, but replication is limited by the broad face, elongated neck, nearly frontal pose and indistinct landscape. Soft gradients give the face some volume. Crossed arms become rounded masses without readable fingers or wrists, and the expression lacks the original's subtlety. Clean framing and curves support an otherwise basic, uneven portrait.

Exact prompt

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

Compare category scores
CategoryClaude Opus 5.5GPT 5.6 Terra
Prompt & likeness7.0/105.0/10
Anatomy & construction6.0/104.0/10
Space & placement6.5/105.5/10
Light & reflections6.0/106.0/10
Purposeful detail6.5/103.5/10
Artistry & character6.5/105.0/10
Materials & effects6.5/104.5/10
Visual integrity7.0/106.5/10

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 Terra72.0/100

GPT 5.6 Terra: Raccoon SVG benchmark
Researcher observations

Expressive faces, a recognizable raccoon perched on the dog, and a sweeping wake make an appealing cartoon. The principal weakness is the steering interaction: the dog's paw sits beside the control assembly without a convincing handlebar grip. Bold outlines and coherent layering provide polish, while simplified shading, compressed seating geometry and angular splashes limit depth and physical credibility.

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 Terra
Prompt & likeness8.5/107.5/10
Anatomy & construction7.0/106.0/10
Space & placement7.5/107.5/10
Light & reflections6.0/106.5/10
Purposeful detail7.5/107.5/10
Artistry & character8.0/108.0/10
Materials & effects7.0/107.0/10
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 Terra70.5/100

GPT 5.6 Terra: Pelican SVG benchmark
Researcher observations

The oversized bill, expressive eye and balanced twilight palette make the cyclist immediately readable. Clean contours and wheel details support the illustration, but the rabbit-like head tufts weaken pelican likeness. The wing does not clearly grip the handlebar, pedal contact is uneven, and the drivetrain is incomplete. Lighting remains mostly decorative.

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 Terra
Prompt & likeness8.5/108.0/10
Anatomy & construction6.5/106.0/10
Space & placement7.0/107.0/10
Light & reflections6.0/106.5/10
Purposeful detail7.5/107.0/10
Artistry & character7.5/107.5/10
Materials & effects6.0/106.5/10
Visual integrity8.5/108.0/10