Claude Opus 5.5 66.3/100Rank 5/47

STEALTHMARK · HEAD TO HEAD
All comparisons ↗Claude Opus 5.5 leads Kimi K3.1 Pro by 15.9 points on StealthMark, 72.6 to 56.7. It leads on all 9 benchmarks. Claude Opus 5.5 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
Claude Opus 5.5 scores higher on StealthMark and runs 42% faster in our speed test. Kimi K3.1 Pro is 2× cheaper per output token. Both take about 1M tokens of context.
Full datasheets, every price and sourceClaude Opus 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 Opus 5.5
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.
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 Opus 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 | 55.0/120 | 26.0/120 |
| Materials and scale | 9.0/10 | 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 Opus 5.5
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.
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 Opus 5.5 | Kimi K3.1 Pro |
|---|---|---|
| Task & likeness | 8.0/10 | 8.0/10 |
| Anatomy & construction | 7.5/10 | 5.5/10 |
| Space & placement | 8.0/10 | 6.5/10 |
| Light & reflections | 7.5/10 | 6.5/10 |
| Purposeful detail | 7.0/10 | 7.5/10 |
| Artistry & character | 7.0/10 | 7.0/10 |
| Materials & effects | 7.0/10 | 7.0/10 |
| Visual integrity | 8.5/10 | 7.0/10 |
Claude Opus 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 Opus 5.5
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.
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 Opus 5.5 | Kimi K3.1 Pro |
|---|---|---|
| Task & likeness | 6.5/10 | 5.0/10 |
| Anatomy & construction | 5.5/10 | 5.0/10 |
| Space & placement | 6.5/10 | 5.5/10 |
| Light & reflections | 6.5/10 | 6.0/10 |
| Purposeful detail | 6.5/10 | 5.5/10 |
| Artistry & character | 6.0/10 | 6.0/10 |
| Materials & effects | 7.0/10 | 5.0/10 |
| Visual integrity | 7.0/10 | 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 Opus 5.5
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.
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 Opus 5.5 | Kimi K3.1 Pro |
|---|---|---|
| Task & likeness | 8.5/10 | 8.5/10 |
| Anatomy & construction | 7.5/10 | 5.5/10 |
| Space & placement | 7.0/10 | 5.5/10 |
| Light & reflections | 7.5/10 | 6.5/10 |
| Purposeful detail | 7.5/10 | 6.5/10 |
| Artistry & character | 8.0/10 | 5.5/10 |
| Materials & effects | 6.5/10 | 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 Opus 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 Opus 5.5
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.
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 Opus 5.5 | Kimi K3.1 Pro |
|---|---|---|
| Task & likeness | 8.5/10 | 7.0/10 |
| Anatomy & construction | 7.5/10 | 5.5/10 |
| Space & placement | 7.5/10 | 6.0/10 |
| Light & reflections | 6.0/10 | 5.5/10 |
| Purposeful detail | 8.5/10 | 7.0/10 |
| Artistry & character | 7.0/10 | 6.0/10 |
| Materials & effects | 7.0/10 | 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 Opus 5.5
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.
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 Opus 5.5 | Kimi K3.1 Pro |
|---|---|---|
| Task & likeness | 8.5/10 | 8.5/10 |
| Anatomy & construction | 8.0/10 | 7.5/10 |
| Space & placement | 7.0/10 | 6.5/10 |
| Light & reflections | 6.0/10 | 6.5/10 |
| Purposeful detail | 8.0/10 | 7.5/10 |
| Artistry & character | 7.5/10 | 7.5/10 |
| Materials & effects | 6.0/10 | 6.5/10 |
| Visual integrity | 8.5/10 | 7.5/10 |
A cycling pelican tests anatomy, riding posture and contact between the bird and the bicycle.