GPT-5.6 Terra 30.1/100Rank 31/47

STEALTHMARK · HEAD TO HEAD
All comparisons ↗GPT-5.6 Terra leads Muse Spark Open by 1.7 points on StealthMark, 45.8 to 44.1. It leads on 7 of 9 benchmarks, including both games, and Muse Spark Open on 2. GPT-5.6 Terra scores higher on Newton's Mirror, with its largest category advantage in state at 600 ms.
See the difference ↘On every task, result quality and reasoning tokens are each compared with all measured models and weighed equally. Each dot is one model.
BENCHMARK BY BENCHMARK
DATASHEET
GPT-5.6 Terra scores higher on StealthMark. Muse Spark Open is 2.8× cheaper per output token and runs 3.6× faster in our speed test. Both take about 1.05M tokens of context.
Full datasheets, every price and sourceGPT-5.6 Terra ↗Muse Spark Open ↗
Anticipating threats and planning ahead. Collect coins while avoiding ghosts. Ghosts move before the player each turn, and collisions cost a life. 3 levels in sequence, up to 66 turns in total. Earlier moves and outcomes carry forward, testing learning across levels.


Cooperative planning and learning from experience. Coordinate two robots to push numbered cores onto matching sockets. Pressure plates hold doors open; moving either robot uses one turn. 5 levels in sequence, up to 152 turns in total. Earlier moves and outcomes carry forward, testing learning across levels.


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


GPT-5.6 Terra
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.
Muse Spark Open
The airborne black blob and deformed paint support the broad contact sequence, although cyan attachment and wheel-directed transport remain partial. The sphere and black blob have substantial framing errors. The dominant limitation is the largely absent mirror system: faint wall circles and isolated highlights provide little evidence of recursive room geometry or curved nested reflections. Oversized compact paint features and diffuse material treatment further limit credit.
| Category | GPT-5.6 Terra | Muse Spark Open |
|---|---|---|
| State at 600 ms | 24.0/25 | 14.0/25 |
| Camera and placement | 6.0/15 | 6.0/15 |
| Reflections | 7.0/120 | 8.0/120 |
| Materials and scale | 5.5/10 | 3.5/10 |
| Floor-damage reward | 0.0/10 | 0.0/10 |
A spinning metal sphere and paint in a mirrored room test physical reasoning, perspective and consistency across repeated reflections.
Visual construction and creative interpretation.


GPT-5.6 Terra
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.
Muse Spark Open
The rounded silhouette and asymmetric expression make an appealing baby elephant, supported by a quiet background and grounding shadow. The protective action remains difficult to read: forefeet cannot be confidently traced into a grip, and seed contact is crowded by fine lines. Controlled simple shapes provide charm, but limited anatomical clarity, shading and surface detail leave the execution uneven.
| Category | GPT-5.6 Terra | Muse Spark Open |
|---|---|---|
| Task & likeness | 7.5/10 | 5.0/10 |
| Anatomy & construction | 5.5/10 | 4.5/10 |
| Space & placement | 7.0/10 | 6.0/10 |
| Light & reflections | 7.5/10 | 5.0/10 |
| Purposeful detail | 6.5/10 | 6.0/10 |
| Artistry & character | 5.5/10 | 5.0/10 |
| Materials & effects | 6.5/10 | 5.0/10 |
| Visual integrity | 5.0/10 | 6.5/10 |
GPT-5.6 Terra
A pale serpent woven into an interlocking knot tests connected anatomy, repeated structure and readable overlaps. Organic surface detail must work with the overall geometry.
Muse Spark Open
A small elephant protecting a delicate seed tests expressive anatomy, physical contact and contrasting organic materials.
Precise visual recall and portrait reconstruction.


GPT-5.6 Terra
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.
Muse Spark Open
A recognizable, orderly interpretation with clean major contours, connected body forms and modest facial shading. Wide eyes, frontal symmetry and schematic hands limit likeness and expression. Layered scenery establishes basic depth, but shallow arm overlaps, flat clothing and sparse fine detail keep the execution basic and uneven.
| Category | GPT-5.6 Terra | Muse Spark Open |
|---|---|---|
| Task & likeness | 4.0/10 | 3.0/10 |
| Anatomy & construction | 3.0/10 | 3.0/10 |
| Space & placement | 4.5/10 | 5.0/10 |
| Light & reflections | 5.0/10 | 4.5/10 |
| Purposeful detail | 4.0/10 | 4.0/10 |
| Artistry & character | 4.0/10 | 3.0/10 |
| Materials & effects | 4.0/10 | 4.0/10 |
| Visual integrity | 6.0/10 | 6.0/10 |
An SVG interpretation of the Mona Lisa tests facial likeness, anatomy and the composition of a familiar portrait.
Creativity, perspective and visual beauty.


GPT-5.6 Terra
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.
Muse Spark Open
A coherent sunset beach with readable activities, balanced framing and controlled colour transitions. Small accessories add interest, but schematic anatomy, limited surface detail, weak directional shadows and a geometric reflection constrain its finish. Most shapes and overlaps remain clean.
| Category | GPT-5.6 Terra | Muse Spark Open |
|---|---|---|
| Task & likeness | 7.5/10 | 8.0/10 |
| Anatomy & construction | 5.0/10 | 6.0/10 |
| Space & placement | 6.0/10 | 6.5/10 |
| Light & reflections | 5.0/10 | 5.5/10 |
| Purposeful detail | 6.5/10 | 6.5/10 |
| Artistry & character | 5.0/10 | 5.5/10 |
| Materials & effects | 5.5/10 | 6.0/10 |
| Visual integrity | 5.0/10 | 8.0/10 |
A busy shoreline at sunset tests scene composition, animal forms and the relationship between light and water reflections.
Physical reasoning, light and visual reconstruction.


GPT-5.6 Terra
This benchmark has not been assessed yet.
Muse Spark Open
This benchmark has not been assessed yet.
A plank, computer mouse and blueberry in a steel room test physical stability, spatial relationships, materials and lighting.
Scene composition and interacting subjects.


GPT-5.6 Terra
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.
Muse Spark Open
Expressive faces, distinct accessories and clean color separation make the scene appealing and recognizable. Character detail is stronger than the functional construction: steering contact, limb overlaps and seating remain ambiguous. The readable hull and lively spray establish motion, while limited directional shading and simplified surfaces constrain depth and physical coherence.
| Category | GPT-5.6 Terra | Muse Spark Open |
|---|---|---|
| Task & likeness | 7.5/10 | 4.0/10 |
| Anatomy & construction | 5.0/10 | 3.0/10 |
| Space & placement | 7.0/10 | 6.0/10 |
| Light & reflections | 6.0/10 | 4.5/10 |
| Purposeful detail | 7.0/10 | 7.0/10 |
| Artistry & character | 5.0/10 | 3.5/10 |
| Materials & effects | 7.0/10 | 5.0/10 |
| Visual integrity | 7.5/10 | 5.0/10 |
A jet-ski scene pairs a canine driver with a raccoon passenger. It tests the placement and contact of interacting subjects, along with vehicle construction.
Subject construction and spatial relationships.


GPT-5.6 Terra
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.
Muse Spark Open
A controlled, appealing cartoon with a recognizable pelican, expressive face and clean curved forms. Feather lines, spokes and bill shading provide useful complexity. Aligned wheels and a ground shadow establish placement, but uncertain pedal contacts and obscured mechanical connections weaken support and riding action. Lighting remains loosely coordinated with the sun.
| Category | GPT-5.6 Terra | Muse Spark Open |
|---|---|---|
| Task & likeness | 6.0/10 | 7.5/10 |
| Anatomy & construction | 6.0/10 | 5.0/10 |
| Space & placement | 7.0/10 | 6.0/10 |
| Light & reflections | 6.5/10 | 5.0/10 |
| Purposeful detail | 7.0/10 | 6.5/10 |
| Artistry & character | 6.5/10 | 5.5/10 |
| Materials & effects | 6.5/10 | 6.0/10 |
| Visual integrity | 7.0/10 | 7.5/10 |
A cycling pelican tests anatomy, riding posture and contact between the bird and the bicycle.