Claude Fable 5.1 34.2/100Rank 39/502 of 3 levels

STEALTHMARK · HEAD TO HEAD
All comparisons ↗Claude Fable 5.1 leads GPT-6.1 Terra by 2.6 points on StealthMark, 63.0 to 60.4. It leads on 7 of 9 benchmarks, including Latch, and GPT-6.1 Terra on 2, including Foresight. 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
Claude Fable 5.1 scores higher on StealthMark. GPT-6.1 Terra is 10× cheaper per output token. Both take about 1M tokens of context.
Full datasheets, every price and sourceClaude Fable 5.1 ↗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 ↗


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.
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 | Claude Fable 5.1 | GPT-6.1 Terra |
|---|---|---|
| State at 600 ms | 24.0/25 | 23.0/25 |
| Camera and placement | 14.0/15 | 11.0/15 |
| Reflections | 48.0/120 | 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.


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.
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 | Claude Fable 5.1 | GPT-6.1 Terra |
|---|---|---|
| Task & likeness | 6.5/10 | 7.5/10 |
| Anatomy & construction | 7.0/10 | 6.5/10 |
| Space & placement | 7.5/10 | 6.5/10 |
| Light & reflections | 6.5/10 | 6.0/10 |
| Purposeful detail | 6.0/10 | 6.5/10 |
| Artistry & character | 7.0/10 | 6.5/10 |
| Materials & effects | 6.5/10 | 6.0/10 |
| Visual integrity | 8.0/10 | 6.0/10 |
Claude Fable 5.1
A coral squid with spreading arms tests connected anatomy, balanced composition and soft surface shading.
GPT-6.1 Terra
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.


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.
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 | Claude Fable 5.1 | GPT-6.1 Terra |
|---|---|---|
| Task & likeness | 5.5/10 | 5.5/10 |
| Anatomy & construction | 6.0/10 | 6.5/10 |
| Space & placement | 6.0/10 | 4.5/10 |
| Light & reflections | 6.0/10 | 6.5/10 |
| Purposeful detail | 5.0/10 | 6.0/10 |
| Artistry & character | 5.5/10 | 6.0/10 |
| Materials & effects | 6.0/10 | 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.


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.
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 | Claude Fable 5.1 | GPT-6.1 Terra |
|---|---|---|
| Task & likeness | 8.5/10 | 8.5/10 |
| Anatomy & construction | 7.0/10 | 7.5/10 |
| Space & placement | 7.0/10 | 6.5/10 |
| Light & reflections | 7.0/10 | 5.5/10 |
| Purposeful detail | 7.5/10 | 7.5/10 |
| Artistry & character | 7.5/10 | 7.0/10 |
| Materials & effects | 6.5/10 | 6.5/10 |
| Visual integrity | 7.5/10 | 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 Fable 5.1
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.


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.
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 | Claude Fable 5.1 | GPT-6.1 Terra |
|---|---|---|
| Task & likeness | 8.5/10 | 6.5/10 |
| Anatomy & construction | 6.5/10 | 5.5/10 |
| Space & placement | 7.0/10 | 6.0/10 |
| Light & reflections | 5.5/10 | 5.0/10 |
| Purposeful detail | 7.0/10 | 7.0/10 |
| Artistry & character | 7.0/10 | 6.0/10 |
| Materials & effects | 6.5/10 | 6.0/10 |
| Visual integrity | 7.5/10 | 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 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.
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 | Claude Fable 5.1 | GPT-6.1 Terra |
|---|---|---|
| Task & likeness | 8.5/10 | 7.0/10 |
| Anatomy & construction | 7.0/10 | 7.0/10 |
| Space & placement | 7.5/10 | 6.0/10 |
| Light & reflections | 6.0/10 | 5.5/10 |
| Purposeful detail | 7.0/10 | 7.0/10 |
| Artistry & character | 7.0/10 | 6.5/10 |
| Materials & effects | 6.0/10 | 5.5/10 |
| Visual integrity | 8.0/10 | 6.0/10 |
A cycling pelican tests anatomy, riding posture and contact between the bird and the bicycle.