GPT-5.6 Sol 62.9/100Rank 8/50

STEALTHMARK · HEAD TO HEAD
All comparisons ↗GPT-6.1 Terra leads GPT-5.6 Sol by 6.3 points on StealthMark, 60.4 to 54.1. It leads on 6 of 9 benchmarks and GPT-5.6 Sol on 3, including both games. GPT-6.1 Terra scores higher on Newton's Mirror, with its largest category advantage in reflections.
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-6.1 Terra scores higher on StealthMark and is 4× cheaper per output token. Both take about 1.05M tokens of context.
Full datasheets, every price and sourceGPT-5.6 Sol ↗GPT-6.1 Terra ↗
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 Sol
The central sphere and paint ordering are supported, but a frontal, centrally converging chamber replaces the required corner perspective. The first wall and floor images have incorrect placement and scale relationships. Sparse reflection cues remain, while continuous outer chains, open lateral sightlines, dense planar light sequences and curved nested spherical imagery are largely missing.
GPT-6.1 Terra
The sphere, airborne black and first reflected silhouettes preserve important geometry within the portrait frame. Paint deformation, contact order and forward transport are supported, with a small crimson endpoint overshoot. Major optical omissions dominate: short finite reflection sequences and smooth bands replace extensive, spatially ordered mirror imagery. Dark gloss and crisp upper emitter shapes provide partial material credit.
| Category | GPT-5.6 Sol | GPT-6.1 Terra |
|---|---|---|
| State at 600 ms | 23.0/25 | 23.0/25 |
| Camera and placement | 6.0/15 | 11.0/15 |
| Reflections | 11.0/120 | 33.0/120 |
| Materials and scale | 7.5/10 | 7.5/10 |
| 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 Sol
Six evenly spaced lobes, outward-facing heads and a clear central hexagon establish the requested knot. The ivory silhouette is controlled, but broad crossing bands resemble rigid strips, shading provides limited muscular volume, and repetitive scale lines extend across black loop openings. Small oval heads have readable eyes and mouths but limited anatomical character or moist surface detail.
GPT-6.1 Terra
A balanced serpent emblem with six attached outward heads, delicate scales and softly rounded bodies. Its compact silhouette reads clearly, but central routing does not establish every alternating crossing or crisp inward corner. Repetitive texture, limited facial anatomy and weak contact shadows constrain its organic character.
| Category | GPT-5.6 Sol | GPT-6.1 Terra |
|---|---|---|
| Task & likeness | 7.5/10 | 7.5/10 |
| Anatomy & construction | 6.0/10 | 6.5/10 |
| Space & placement | 7.0/10 | 6.5/10 |
| Light & reflections | 5.0/10 | 6.0/10 |
| Purposeful detail | 6.0/10 | 6.5/10 |
| Artistry & character | 6.5/10 | 6.5/10 |
| Materials & effects | 4.5/10 | 6.0/10 |
| Visual integrity | 6.0/10 | 6.0/10 |
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.
Precise visual recall and portrait reconstruction.


GPT-5.6 Sol
The crossed hands, dark dress and winding landscape establish the Mona Lisa composition. Replication is limited by enlarged eyes, an elongated face and a more frontal pose. Broad gradients suggest volume, but outlined features and flattened, overlapping fingers weaken the portrait. The frame and restrained palette unify the image; visible grain adds texture without convincing painterly transitions.
GPT-6.1 Terra
A recognizable interpretation with developed facial shading, shaped sleeve folds and purposeful small features. These strengths support modest upward calibration, while the frontal torso, elongated proportions, schematic finger joints and unresolved seated support keep replication and construction uneven.
| Category | GPT-5.6 Sol | GPT-6.1 Terra |
|---|---|---|
| Task & likeness | 4.5/10 | 5.5/10 |
| Anatomy & construction | 4.0/10 | 6.5/10 |
| Space & placement | 5.5/10 | 4.5/10 |
| Light & reflections | 5.0/10 | 6.5/10 |
| Purposeful detail | 5.0/10 | 6.0/10 |
| Artistry & character | 4.5/10 | 6.0/10 |
| Materials & effects | 5.5/10 | 6.0/10 |
| Visual integrity | 6.5/10 | 6.5/10 |
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 Sol
The purple-to-gold sunset, framing palms and varied beach activities create an appealing, coherent illustration. The sun’s reflection establishes a clear focal path. Figures and animals are recognizable but geometrically simplified; airborne dolphins lack convincing splashes, and the boat reflection is schematic. Clean silhouettes and playful details succeed more strongly than anatomical depth or material realism.
GPT-6.1 Terra
A coherent sunset illustration with clear prompt fulfillment, controlled framing and varied, purposeful small details. Simplified joints, frontal staging, flattened animal forms and weakly directional shadows limit its anatomical, spatial and physical sophistication.
| Category | GPT-5.6 Sol | GPT-6.1 Terra |
|---|---|---|
| Task & likeness | 8.5/10 | 8.5/10 |
| Anatomy & construction | 6.0/10 | 7.5/10 |
| Space & placement | 7.0/10 | 6.5/10 |
| Light & reflections | 6.5/10 | 5.5/10 |
| Purposeful detail | 7.0/10 | 7.5/10 |
| Artistry & character | 6.5/10 | 7.0/10 |
| Materials & effects | 6.5/10 | 6.5/10 |
| Visual integrity | 7.0/10 | 7.5/10 |
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 Sol
This benchmark has not been assessed yet.
GPT-6.1 Terra
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 Sol
Expressive faces, bold silhouettes and layered waves make an appealing cartoon. The raccoon sits convincingly behind the dog's shoulders, and the dog's forward paw reaches the steering grip. Steering construction and seated support remain somewhat ambiguous. The glowing sunset lacks a corresponding warm reflection or consistent illumination on the riders.
GPT-6.1 Terra
A coherent cartoon with expressive animals, readable steering and a clear wake. Fine facial and hull details reward inspection. The main limits are the boatlike craft, simplified joints, weakly braced frontal raccoon and minimal directional lighting or material depth.
| Category | GPT-5.6 Sol | GPT-6.1 Terra |
|---|---|---|
| Task & likeness | 6.5/10 | 6.5/10 |
| Anatomy & construction | 5.0/10 | 5.5/10 |
| Space & placement | 6.5/10 | 6.0/10 |
| Light & reflections | 6.5/10 | 5.0/10 |
| Purposeful detail | 7.5/10 | 7.0/10 |
| Artistry & character | 5.0/10 | 6.0/10 |
| Materials & effects | 7.0/10 | 6.0/10 |
| Visual integrity | 5.0/10 | 7.0/10 |
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 Sol
The expressive pelican and balanced coastal composition remain appealing, but a sky-colored slit between the neck contours above the wing leaves the central anatomy incoherent. This visible construction and layering defect prevents a clean-integrity assessment. Clustered feet lack clear pedal contacts and the chain routing is schematic; lighting and water reflections remain graphic.
GPT-6.1 Terra
A coherent pelican cyclist with expressive proportions, purposeful feather detail and developed bicycle machinery. Continuous body contours, aligned wheels and readable pedal contacts support the scene. Simplified articulation, shallow modelling and an unresolved steering connection limit construction and placement.
| Category | GPT-5.6 Sol | GPT-6.1 Terra |
|---|---|---|
| Task & likeness | 8.5/10 | 7.0/10 |
| Anatomy & construction | 5.0/10 | 7.0/10 |
| Space & placement | 7.5/10 | 6.0/10 |
| Light & reflections | 7.5/10 | 5.5/10 |
| Purposeful detail | 8.0/10 | 7.0/10 |
| Artistry & character | 6.5/10 | 6.5/10 |
| Materials & effects | 7.0/10 | 5.5/10 |
| Visual integrity | 4.5/10 | 6.0/10 |
A cycling pelican tests anatomy, riding posture and contact between the bird and the bicycle.