Claude Fable 5.1 34.2/100Rank 38/492 of 3 levels

STEALTHMARK · HEAD TO HEAD
All comparisons ↗Claude Fable 5.1 leads Step 5 Preview by 24.0 points on StealthMark, 63.0 to 39.0. It leads on all 9 benchmarks. Claude Fable 5.1 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 Fable 5.1 ↗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 Fable 5.1
The broad paint sequence, bilateral near-field sphere arrangement, overlaps and diminishing panel repetitions are recognizable; crimson is slightly too low. Small paint scale and basic shading provide material cues, although the steel response remains soft. Inaccurate light projections, missing outer chains and incomplete nested room imagery remain the principal limitations.
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 Fable 5.1 | Step 5 Preview |
|---|---|---|
| State at 600 ms | 24.0/25 | 20.0/25 |
| Camera and placement | 14.0/15 | 13.5/15 |
| Reflections | 48.0/120 | 20.0/120 |
| Materials and scale | 7.5/10 | 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 Fable 5.1
The coral palette, friendly face, matte shading and cream arch create a coherent emblem. However, the mantle is elongated rather than compact, and the appendages spread mostly sideways and downward instead of forming an evenly spaced, flower-like starburst. Two thin hanging appendages weaken the thick-arm motif. Clean contours and balanced framing support the simple design.
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 Fable 5.1 | Step 5 Preview |
|---|---|---|
| Task & likeness | 6.5/10 | 6.0/10 |
| Anatomy & construction | 7.0/10 | 4.5/10 |
| Space & placement | 7.5/10 | 5.0/10 |
| Light & reflections | 6.5/10 | 5.5/10 |
| Purposeful detail | 6.0/10 | 5.5/10 |
| Artistry & character | 7.0/10 | 5.0/10 |
| Materials & effects | 6.5/10 | 6.0/10 |
| Visual integrity | 8.0/10 | 5.0/10 |
Claude Fable 5.1
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 Fable 5.1
The dark clothing, crossed hands and hazy landscape establish the Mona Lisa composition. Replication is limited by the frontal, elongated face, wide eyes and simplified smile. Rounded, parallel fingers and unclear wrist transitions weaken the hands. Warm facial shading gives some volume, but broad garment shapes and scattered crack marks substitute for convincing folds and painterly detail.
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 Fable 5.1 | Step 5 Preview |
|---|---|---|
| Task & likeness | 5.5/10 | 4.0/10 |
| Anatomy & construction | 6.0/10 | 4.0/10 |
| Space & placement | 6.0/10 | 4.0/10 |
| Light & reflections | 6.0/10 | 3.5/10 |
| Purposeful detail | 5.0/10 | 4.0/10 |
| Artistry & character | 5.5/10 | 4.0/10 |
| Materials & effects | 6.0/10 | 3.0/10 |
| Visual integrity | 6.5/10 | 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 Fable 5.1
The colorful sunset, layered shoreline, animals, kite and beach toys fulfill the lively beach brief. Clean silhouettes and a balanced composition give the illustration character. Construction is simplified: the umbrella resembles a segmented fan, dolphins have weak water interaction, and the sun’s reflection forms a rigid widening wedge. Flat surfaces and sparse contact shadows limit depth.
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 Fable 5.1 | Step 5 Preview |
|---|---|---|
| Task & likeness | 8.5/10 | 4.0/10 |
| Anatomy & construction | 7.0/10 | 3.0/10 |
| Space & placement | 7.0/10 | 3.5/10 |
| Light & reflections | 7.0/10 | 3.5/10 |
| Purposeful detail | 7.5/10 | 3.0/10 |
| Artistry & character | 7.5/10 | 3.0/10 |
| Materials & effects | 6.5/10 | 3.5/10 |
| Visual integrity | 7.5/10 | 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 Fable 5.1
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 Fable 5.1
The raccoon rides on the dog's back, and the dog's extended foreleg reaches the jet ski controls. Expressive faces, a clear silhouette and sweeping spray make the action readable. Limb and handlebar overlaps weaken construction; broad shading provides limited volume, and the glowing sun has little corresponding reflection on the water. Clean vector shapes support an appealing but simplified illustration.
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 Fable 5.1 | Step 5 Preview |
|---|---|---|
| Task & likeness | 8.5/10 | 4.0/10 |
| Anatomy & construction | 6.5/10 | 4.5/10 |
| Space & placement | 7.0/10 | 3.0/10 |
| Light & reflections | 5.5/10 | 3.5/10 |
| Purposeful detail | 7.0/10 | 4.0/10 |
| Artistry & character | 7.0/10 | 3.5/10 |
| Materials & effects | 6.5/10 | 3.0/10 |
| Visual integrity | 7.5/10 | 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 Fable 5.1
The pelican reads clearly, with an expressive face, prominent bill and appealing composition. Both legs connect to the body, but the far foot's pedal contact and the wing's steering grip remain unclear. Wheel alignment and background layers are coherent. Clean contours and feather lines give polish, while schematic machinery, limited surface texture and weak directional lighting constrain the finish.
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 Fable 5.1 | Step 5 Preview |
|---|---|---|
| Task & likeness | 8.5/10 | 3.0/10 |
| Anatomy & construction | 7.0/10 | 3.0/10 |
| Space & placement | 7.5/10 | 3.0/10 |
| Light & reflections | 6.0/10 | 3.0/10 |
| Purposeful detail | 7.0/10 | 4.0/10 |
| Artistry & character | 7.0/10 | 3.0/10 |
| Materials & effects | 6.0/10 | 3.0/10 |
| Visual integrity | 8.0/10 | 2.0/10 |
A cycling pelican tests anatomy, riding posture and contact between the bird and the bicycle.