PYTHON · NUMPY

Capstone — author and ship a skill

Write a skill contract, validate it, gate it, and run it inside its own safety envelope.

01Challenge

Author a gripper-grasp skill as a contract you own. Validate its required fields, gate it correctly (it needs the gripper DoF, so 4-DoF arms are refused), and run it through its own envelope to a grasp.

02Model

You've built every layer: capability negotiation, the runtime envelope, policy-agnosticism, LeRobot composition, the safe protocol. A skill is just those, packaged as source you own — a manifest with a policy, requirements, a safety envelope, and a contract. Ship it and it installs like a component, runs on any compatible body, and can't break the ones it can't.

03Guided practice

1. Author. A skill dict: name, version, policy, requires, safety, contract. 2. Validate. Every required field present. 3. Gate. Compatible on a 5-DoF arm, refused on a 4-DoF one (no gripper DoF). 4. Run. Through its own max_step_norm to a grasp config.

04Feedback

PASS WHEN PASS when your skill validates, gates correctly, and reaches the grasp under its envelope.

If your run fails, check:

Read the bench’s printed result — it passes when your skill validates, gates correctly, and reaches the grasp under its envelope. Run the cells top to bottom; if one errors, the FAIL line names the step to fix.
min_dof 5 must refuse the 4-DoF Maestro; the grasp must converge under 0.06/tick.

05Retrieve & space

What five things make a skill? (a manifest: policy, requires, safety, contract, eval).
Why does gripper-grasp refuse a 4-DoF arm? (it needs the gripper degree of freedom).
What do you own when you install a skill? (the source — the contract — not a vendor binary).

06Mastery & project

You can author, validate, gate, and safely run a skill end-to-end.

Add a real skill to the open registry: a skill.json contract, a policy, an eval — and open a PR.

GO FURTHER · THE LIVE PLAYGROUND

The open standard: SPEC, schema, and how to contribute a skill ↗ — skillpack is Apache-2.0 — author a skill and ship it.

← MCP for robots, done right Back to course →

PYTHON · NUMPY

Capstone — author and ship a skill

Author a skill, validate it, gate it, run it — the whole layer in one bench.

You read

the arrays and values already in scope

You change

the code you write in each cell

Fixed

the dataset and the checks that grade you