CYBORGS OF EARTH
Cyborg Index · July 2026

Fourier GR-2 vs Kepler Forerunner K2

Both humanoids read on the same 8 axes and 40 sub-axes, using the published Index scores. Every difference below carries the public evidence behind it, and sub-axes with no public evidence count as 0 rather than being skipped.

The public record is still thin on at least one side of this pair, so treat the ordering as provisional rather than settled.

Overall standing

Capability score · 0–5 over 40 sub-axes
Fourier GR-2
Fourier Intelligence
0.57of 5
Rank
#11
Coverage
14/40
Proof
0.06
Kepler Forerunner K2
Kepler Robotics
1.32of 5
Rank
#3
Coverage
26/40
Proof
0.06
The short answer

Kepler Forerunner K2 scores 0.75 higher than Fourier GR-2, but that lead rests mostly on vendor claims and demos.

Only 5% of Kepler Forerunner K2's score is carried by independently verified material — the rest is claimed or shown in demos. Fourier GR-2 has more unscored ground than the gap between them, so this could change next month.

Where Fourier GR-2 is ahead

Not ahead by enough on any axis to be worth reporting.

Where Kepler Forerunner K2 is ahead
  • HRI+1.40Rests on claims and demos
  • Locomotion+1.20Rests on claims and demos
  • Manipulation+1.00Rests on claims and demos
  • Learning+0.80Rests on claims and demos
What would change it

15 sub-axes on the trailing side have no public evidence yet. If all of them scored full marks they would be worth 1.88 — against a gap of 0.75.

  • Learning · Foundation policyup to +0.125
  • HRI · Nl instructionup to +0.125
  • Perception · Semantic world modelup to +0.125
  • Autonomy · Instruction followingup to +0.125
  • HRI · Speech ioup to +0.125
There is more unscored ground than there is gap, so this result could turn over after the next research month.
How much we know
50%of sub-axes covered

We have public evidence for 50% of the 40 sub-axes across these two.

Fourier GR-2 · 35%
Kepler Forerunner K2 · 65%
The shape of each score
Fourier GR-20.57
LocomotionManipulationPerceptionAutonomyLearningHRIDeploymentSafety

14/40 sub-axes have evidence

Faint outline = Kepler Forerunner K2

Kepler Forerunner K21.32
LocomotionManipulationPerceptionAutonomyLearningHRIDeploymentSafety

26/40 sub-axes have evidence

Faint outline = Fourier GR-2

Reading the wheels — clockwise from the top
  1. 1 Locomotion
  2. 2 Manipulation
  3. 3 Perception
  4. 4 Autonomy
  5. 5 Learning
  6. 6 HRI
  7. 7 Deployment
  8. 8 Safety

Each wheel has 40 spokes — five per axis. A longer spoke is a higher score, and the dashed rings mark 1 to 4. Hover or tab onto any spoke to read the axis, the sub-axis and the exact value. A missing spoke means there is no public evidence for that sub-axis yet, which is not the same as scoring zero. The faint outline on each wheel is the other humanoid, drawn on the same scale.

Every axis, every sub-axis
HRI1.40Locomotion1.20Manipulation1.00Learning0.80Autonomy0.80Perception0.40Deployment0.40Safetylevel
Fourier GR-2Kepler Forerunner K2
Shared 0–5 track · widest gap first
HRI
0.40 / 1.80► 1.40
Rests on claims and demosEvidenced cells · 1/5 vs 4/5
Speech io
— / 2.00► 2.00
Nl instruction
— / 3.00► 3.00
Intent recognition
— / —
Safe proximity
2.00 / 2.00
Social presentation
— / 2.00► 2.00
Locomotion
0.80 / 2.00► 1.20
Rests on claims and demosEvidenced cells · 2/5 vs 4/5
Flat ground walking
2.00 / 2.00
Uneven terrain
— / 3.00► 3.00
Stairs
— / —
Disturbance recovery
— / 3.00► 3.00
Speed endurance
2.00 / 2.00
Manipulation
0.80 / 1.80► 1.00
Rests on claims and demosEvidenced cells · 2/5 vs 3/5
Grasp variety
2.00 / 3.00► 1.00
Bimanual
— / 4.00► 4.00
Force control
2.00 / 2.00
In hand reorient
— / —
Tool use
— / —
Learning
0.20 / 1.00► 0.80
Rests on claims and demosEvidenced cells · 1/5 vs 2/5
Imitation learning
— / 2.00► 2.00
Sim to real
1.00 / —◄ 1.00
Foundation policy
— / 3.00► 3.00
Data flywheel
— / —
Transfer fine tune
— / —
Autonomy
0.40 / 1.20► 0.80
Rests on claims and demosEvidenced cells · 2/5 vs 4/5
Unattended operation
1.00 / 0.00◄ 1.00
Task horizon
1.00 / 3.00► 2.00
Generalization
— / 1.00► 1.00
Instruction following
— / 2.00► 2.00
Recovery from failure
— / —
Perception
1.00 / 1.40► 0.40
Rests on claims and demosEvidenced cells · 3/5 vs 4/5
Sensor stack
2.00 / 2.00
Scene understanding
1.00 / 1.00
Spatial memory
2.00 / 2.00
Object permanence
— / —
Semantic world model
— / 2.00► 2.00
Deployment
0.80 / 1.20► 0.40
Rests on claims and demosEvidenced cells · 2/5 vs 4/5
Named pilots
— / 1.00► 1.00
Field hours
— / 1.00► 1.00
Customer diversity
— / 3.00► 3.00
Supportability
2.00 / —◄ 2.00
Commercial posture
2.00 / 1.00◄ 1.00
Safety
0.20 / 0.20
Not enough public record yetEvidenced cells · 1/5 vs 1/5
Functional safety
— / 1.00► 1.00
Certifications
— / —
E stop arch
— / —
Incident transparency
— / —
Force impact limits
1.00 / —◄ 1.00
Segment length and thickness are the gapNo public evidence yet
Which is better for what

Each row is decided by the axes that matter for that kind of work, read off the same Capability scores as the ranking. Rows only appear where both humanoids have enough public record to answer.

Manufacturing and warehouse work
Named pilots and field hours, backed by what the hands can actually do.
Kepler Forerunner K2
Kepler Forerunner K2 scores higher on Deployment and Manipulation — 1.40 against 0.80 for Fourier GR-2.
Running without a human in the loop
Unattended operation and task horizon, backed by what the robot can perceive.
Kepler Forerunner K2
Kepler Forerunner K2 scores higher on Autonomy and Perception — 1.27 against 0.60 for Fourier GR-2.
Moving through difficult ground
Uneven terrain, stairs and disturbance recovery.
Kepler Forerunner K2
Kepler Forerunner K2 scores higher on Locomotion — 2.00 against 0.80 for Fourier GR-2.
Working alongside people
Functional safety and certification, plus how it reads and answers people.
Kepler Forerunner K2
Kepler Forerunner K2 scores higher on Safety and HRI — 0.73 against 0.27 for Fourier GR-2.
Picking up new tasks
Imitation learning, transfer and generalisation across tasks.
Kepler Forerunner K2
Kepler Forerunner K2 scores higher on Learning and Autonomy — 1.07 against 0.27 for Fourier GR-2.
Research and developer use
How much of the stack is documented and reproducible.
Kepler Forerunner K2
Kepler Forerunner K2 scores higher on Learning and Perception — 1.13 against 0.47 for Fourier GR-2.
How solid the record is on each side
Fourier GR-2
Sub-axes on the record
14 of 40 · 35%
Carried by verified material
10%
Rests on claims and demos
0.51
Best documented — Perception
Nothing on the record — every axis has at least one read
Kepler Forerunner K2
Sub-axes on the record
26 of 40 · 65%
Carried by verified material
5%
Rests on claims and demos
1.26
Best documented — Locomotion, Manipulation, Perception, Autonomy, HRI, Deployment
Nothing on the record — every axis has at least one read

What this comparison cannot settle

  • Neither humanoid has a public read on 11 of the 40 sub-axes, so those cannot be compared at all.
  • 18 sub-axes are read on only one side. A one-sided cell is undecided, not a zero for the silent side.
  • Most of Fourier GR-2's score rests on vendor statements and demo footage rather than independently verified material (10% carried by verified evidence).
  • Most of Kepler Forerunner K2's score rests on vendor statements and demo footage rather than independently verified material (5% carried by verified evidence).
  • Demonstrations happen in different environments and product revisions are not always equivalent, so like-for-like uptime and throughput figures do not exist for most of the field.

Go deeper on either humanoid

Nearby comparisons

All comparisons →
Cyborg IndexJuly 2026 editionCapability scoremethodology