Claude Opus 5.5 66.3/100Rank 5/49

STEALTHMARK · HEAD TO HEAD
All comparisons ↗Claude Opus 5.5 leads Step 5 Preview by 33.6 points on StealthMark, 72.6 to 39.0. 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
Both take about 1M tokens of context.
Full datasheets, every price and sourceClaude Opus 5.5 ↗Step 5 Preview ↗
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.
Step 5 Preview
The main sphere, airborne black and small colored features occupy broadly appropriate positions. Most of the defining mirror system is absent, and paint interaction remains only partially supported. The small paint features do not visibly establish a separate volume-scale violation.
| Category | Claude Opus 5.5 | Step 5 Preview |
|---|---|---|
| State at 600 ms | 24.0/25 | 20.0/25 |
| Camera and placement | 15.0/15 | 13.5/15 |
| Reflections | 55.0/120 | 20.0/120 |
| 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.
Step 5 Preview
A charming diagonal climber and warm palette communicate the central idea. Simple rounded construction, crowded limb counting, uncertain footholds and an unattached upper shelf limit its physical coherence. Growth bands and the yarn trail add specificity, but the requested material distinctions and unravelled bootie remain underdeveloped.
| Category | Claude Opus 5.5 | Step 5 Preview |
|---|---|---|
| Task & likeness | 8.0/10 | 6.0/10 |
| Anatomy & construction | 7.5/10 | 4.5/10 |
| Space & placement | 8.0/10 | 5.0/10 |
| Light & reflections | 7.5/10 | 5.5/10 |
| Purposeful detail | 7.0/10 | 5.5/10 |
| Artistry & character | 7.0/10 | 5.0/10 |
| Materials & effects | 7.0/10 | 6.0/10 |
| Visual integrity | 8.5/10 | 5.0/10 |
Claude Opus 5.5
A coral squid with spreading arms tests connected anatomy, balanced composition and soft surface shading.
Step 5 Preview
Character scenes test expression, anatomy, materials and coherent visual construction.
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.
Step 5 Preview
A recognizable, coherent simplification with purposeful facial contours and differentiated fingers. These provide more construction and detail than the broad silhouette alone suggests. The oversized face, frontal seated pose, unresolved wrists and sparse landscape still substantially limit likeness, depth and finish.
| Category | Claude Opus 5.5 | Step 5 Preview |
|---|---|---|
| Task & likeness | 6.5/10 | 4.0/10 |
| Anatomy & construction | 5.5/10 | 4.0/10 |
| Space & placement | 6.5/10 | 4.0/10 |
| Light & reflections | 6.5/10 | 3.5/10 |
| Purposeful detail | 6.5/10 | 4.0/10 |
| Artistry & character | 6.0/10 | 4.0/10 |
| Materials & effects | 7.0/10 | 3.0/10 |
| Visual integrity | 7.0/10 | 3.5/10 |
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.
Step 5 Preview
A recognizable sunset beach with clear warm-cool contrast and playful accessories. Basic animal construction, shallow foreground placement and schematic reflections limit spatial and physical credibility. Sparse descriptive detail and abruptly ended sky bands constrain the finish.
| Category | Claude Opus 5.5 | Step 5 Preview |
|---|---|---|
| Task & likeness | 8.5/10 | 4.0/10 |
| Anatomy & construction | 7.5/10 | 3.0/10 |
| Space & placement | 7.0/10 | 3.5/10 |
| Light & reflections | 7.5/10 | 3.5/10 |
| Purposeful detail | 7.5/10 | 3.0/10 |
| Artistry & character | 8.0/10 | 3.0/10 |
| Materials & effects | 6.5/10 | 3.5/10 |
| Visual integrity | 8.0/10 | 4.0/10 |
A busy shoreline at sunset tests scene composition, animal forms and the relationship between light and water reflections.
Physical reasoning, light and visual reconstruction.


Claude Opus 5.5
This benchmark has not been assessed yet.
Step 5 Preview
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.
Step 5 Preview
Recognizable animals, a bright palette and identifying accessories support a basic cartoon. Primitive anatomy, partial seated support, unresolved steering and weak hull-water contact limit the central action. Lighting and spray provide atmosphere without establishing convincing physical depth.
| Category | Claude Opus 5.5 | Step 5 Preview |
|---|---|---|
| Task & likeness | 8.5/10 | 4.0/10 |
| Anatomy & construction | 7.5/10 | 4.5/10 |
| Space & placement | 7.5/10 | 3.0/10 |
| Light & reflections | 6.0/10 | 3.5/10 |
| Purposeful detail | 8.5/10 | 4.0/10 |
| Artistry & character | 7.0/10 | 3.5/10 |
| Materials & effects | 7.0/10 | 3.0/10 |
| Visual integrity | 8.0/10 | 3.0/10 |
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.
Step 5 Preview
The pelican and bicycle are recognizable, with a pleasant palette and basic diffuse shading. The riding relationship fails physically: the bird is unsupported, the front wheel is unmounted, and pedalling is unresolved. Simple geometric construction and sparse material treatment further limit the drawing.
| Category | Claude Opus 5.5 | Step 5 Preview |
|---|---|---|
| Task & likeness | 8.5/10 | 3.0/10 |
| Anatomy & construction | 8.0/10 | 3.0/10 |
| Space & placement | 7.0/10 | 3.0/10 |
| Light & reflections | 6.0/10 | 3.0/10 |
| Purposeful detail | 8.0/10 | 4.0/10 |
| Artistry & character | 7.5/10 | 3.0/10 |
| Materials & effects | 6.0/10 | 3.0/10 |
| Visual integrity | 8.5/10 | 2.0/10 |
A cycling pelican tests anatomy, riding posture and contact between the bird and the bicycle.