Claude Sonnet 5.5 59.6/100Rank 11/47

STEALTHMARK · HEAD TO HEAD
All comparisons ↗Claude Sonnet 5.5 leads Kimi K3.1 Pro by 13.5 points on StealthMark, 70.2 to 56.7. It leads on 8 of 9 benchmarks, including Latch, and Kimi K3.1 Pro on 1, including Foresight. Claude Sonnet 5.5 scores higher on Ground Truth.
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
Claude Sonnet 5.5 scores higher on StealthMark and runs 2.1× faster in our speed test. Both take about 1M tokens of context.
Full datasheets, every price and sourceClaude Sonnet 5.5 ↗Kimi K3.1 Pro ↗
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 ↗


Claude Sonnet 5.5
The near-field silhouettes, broad perspective and paint contact order are recognizable. Missing outer chains, truncated repetitions and absent ordered imagery within the main and reflected spheres substantially limit the reflection system. Sparse spherical highlights leave much of the curved room and emitter mapping unsupported, despite some plausible planar light sequences.
Kimi K3.1 Pro
The settled sphere, separate airborne black paint and crimson-before-cyan interaction are supported, with a modest crimson travel overshoot. A shared downward framing displacement remains after accounting for the square canvas. The principal limitation is the reflection system: sparse sphere copies and generic curved bands omit most of the ordered mirror-room structure. Materials receive a small upward revision because bounded bright images and dark bands visibly establish some polish, while soft shading and bulky paint remain separate weaknesses.
| Category | Claude Sonnet 5.5 | Kimi K3.1 Pro |
|---|---|---|
| State at 600 ms | 24.0/25 | 23.5/25 |
| Camera and placement | 15.0/15 | 10.5/15 |
| Reflections | 35.0/120 | 26.0/120 |
| Materials and scale | 10.0/10 | 7.0/10 |
| 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.


Claude Sonnet 5.5
The centered coral squid has a friendly, composed expression and a balanced flower-like silhouette. Eight thick arms and two slender tentacles remain visibly connected, with no inverted parts. The mantle is elongated rather than compact, and the arm spacing is uneven. Soft shading gives volume, but dense stippling weakens the requested smooth matte finish; the broad background halo makes depth less precise.
Kimi K3.1 Pro
The transformed reflection, attentive pose and constellation anatomy clearly communicate introspection. Purposeful fine details enrich a coherent composition. Tubular limbs, crowded lower-body overlaps, shallow depth and limited cast lighting keep the overall execution within the competent range.
| Category | Claude Sonnet 5.5 | Kimi K3.1 Pro |
|---|---|---|
| Task & likeness | 8.0/10 | 8.0/10 |
| Anatomy & construction | 8.0/10 | 5.5/10 |
| Space & placement | 8.0/10 | 6.5/10 |
| Light & reflections | 7.5/10 | 6.5/10 |
| Purposeful detail | 8.0/10 | 7.5/10 |
| Artistry & character | 8.0/10 | 7.0/10 |
| Materials & effects | 8.0/10 | 7.0/10 |
| Visual integrity | 8.5/10 | 7.0/10 |
Claude Sonnet 5.5
A coral squid with spreading arms tests connected anatomy, balanced composition and soft surface shading.
Kimi K3.1 Pro
An imagined creature encounters its reflection. The scene tests original character design, visual self-interpretation and the relationship between a subject and its reflected image.
Precise visual recall and portrait reconstruction.


Claude Sonnet 5.5
The crossed hands, dark dress, restrained smile and winding landscape clearly recall the Mona Lisa. Replication is limited by the frontal symmetry, wide eyes, elongated neck and flattened fingers. Soft facial shading provides volume, but heavy darkness and pervasive crackle obscure forms. The composition is coherent; the landscape and fabric remain visibly schematic.
Kimi K3.1 Pro
A coherent, recognizable interpretation with controlled color and readable landscape layers. Replication is limited by the frontal seated construction, elongated facial proportions and oversized, weakly articulated hands. Smooth shading supplies some volume but little of the reference's subtle expression, fabric structure or atmospheric transitions.
| Category | Claude Sonnet 5.5 | Kimi K3.1 Pro |
|---|---|---|
| Task & likeness | 6.5/10 | 5.0/10 |
| Anatomy & construction | 5.0/10 | 5.0/10 |
| Space & placement | 6.0/10 | 5.5/10 |
| Light & reflections | 6.5/10 | 6.0/10 |
| Purposeful detail | 6.0/10 | 5.5/10 |
| Artistry & character | 6.5/10 | 6.0/10 |
| Materials & effects | 6.0/10 | 5.0/10 |
| 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.


Claude Sonnet 5.5
A richly designed beach illustration combines radiant sunset bands, intricate palm fans and playful silhouettes within a cohesive purple, coral and turquoise palette. Carefully varied accessories reward close inspection, while overlapping foreground forms and shoreline layers organize the abundant activity. Dense palm strokes compete with focal subjects; animal anatomy, relative scales and reflected silhouettes remain simplified.
Kimi K3.1 Pro
A coherent, playful beach illustration with readable animals, an organized composition and an aligned sunset reflection. Connected silhouettes, sand texture and atmospheric effects demonstrate controlled execution. Simplified joints, flattened foreground viewpoints and inconsistent shadows limit anatomical and spatial credibility.
| Category | Claude Sonnet 5.5 | Kimi K3.1 Pro |
|---|---|---|
| Task & likeness | 9.0/10 | 8.5/10 |
| Anatomy & construction | 8.0/10 | 5.5/10 |
| Space & placement | 8.5/10 | 5.5/10 |
| Light & reflections | 8.5/10 | 6.5/10 |
| Purposeful detail | 9.5/10 | 6.5/10 |
| Artistry & character | 9.5/10 | 5.5/10 |
| Materials & effects | 8.5/10 | 6.5/10 |
| Visual integrity | 8.0/10 | 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.


Claude Sonnet 5.5
This benchmark has not been assessed yet.
Kimi K3.1 Pro
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.


Claude Sonnet 5.5
The raccoon clearly rides on the dog's back while the dog grips the jet ski controls. Expressive faces, vivid colors and a sweeping wake make the scene appealing. Visible limbs connect coherently, but overlapping steering paws and an indistinct control mounting weaken construction. Flat character lighting and simplified water limit depth and material realism.
Kimi K3.1 Pro
The additional comparisons support retaining the assessment. Readable steering, shaped animal contours and purposeful details coexist with simplified joints, a frontal passenger whose seated weight is weakly conveyed, and limited physical lighting. The angled craft establishes more depth than the riding pose resolves.
| Category | Claude Sonnet 5.5 | Kimi K3.1 Pro |
|---|---|---|
| Task & likeness | 8.5/10 | 7.0/10 |
| Anatomy & construction | 7.0/10 | 5.5/10 |
| Space & placement | 8.0/10 | 6.0/10 |
| Light & reflections | 6.5/10 | 5.5/10 |
| Purposeful detail | 8.0/10 | 7.0/10 |
| Artistry & character | 7.0/10 | 6.0/10 |
| Materials & effects | 7.5/10 | 6.0/10 |
| Visual integrity | 8.0/10 | 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.


Claude Sonnet 5.5
The pelican is immediately recognizable, with an expressive face, generous bill and appealing cycling pose. Spokes, chain, feathers and scarf provide purposeful detail. The bicycle largely holds together, though overlapping angular legs obscure the far foot’s pedal contact. Clean outlines and balanced composition succeed; flat surfaces and limited directional lighting constrain depth.
Kimi K3.1 Pro
A characterful coastal illustration with controlled contours and varied feather, accessory and bicycle detail. Layered scenery and subtle shading enrich the presentation. Soft leg articulation, unresolved riding contacts, shallow depth and generalized lighting limit physical precision.
| Category | Claude Sonnet 5.5 | Kimi K3.1 Pro |
|---|---|---|
| Task & likeness | 9.0/10 | 8.5/10 |
| Anatomy & construction | 7.5/10 | 7.5/10 |
| Space & placement | 7.5/10 | 6.5/10 |
| Light & reflections | 6.5/10 | 6.5/10 |
| Purposeful detail | 8.0/10 | 7.5/10 |
| Artistry & character | 7.5/10 | 7.5/10 |
| Materials & effects | 6.5/10 | 6.5/10 |
| Visual integrity | 8.0/10 | 7.5/10 |
A cycling pelican tests anatomy, riding posture and contact between the bird and the bicycle.