PYTHON · NUMPY · IN-BROWSER

Does it obey?

Prove the policy follows the instruction rather than chasing a fixed target, by flipping which colour you ask for.

01Challenge

Show that each instruction produces an action pointing at its own named target — the test of real language grounding.

02Model

A policy that always reaches the same block would look like it understands language while ignoring it. The honest test is to flip the instruction and check the behaviour flips too. Ask for green and the action points at green; ask for red and it points at red — same scene, different word, different move. This is exactly the measurement behind the headline number on our released nano-VLAs: reach the correct target 97 percent of the time, and 0 percent when the instruction is flipped. That zero is the proof the language is load-bearing, not decoration.

03Guided practice

1. Rebuild the VLA. Each lesson stands alone, so set the policy up again. 2. Flip the instruction. Feed 'green', then 'red', on the same scene. 3. Read the result. Each action aligns with its own target, and the two actions differ. If flipping the word flips the target, the language is doing the work.

04Feedback

PASS WHEN PASS when each instruction points at its own named target and the two actions differ.

A cell errored — run them in order.
Each instruction should aim at the target it names.

05Retrieve & space

What does flipping the instruction test? (whether the policy obeys language or ignores it).
On our released nano-VLAs, what is the success rate when the instruction is flipped? (0% — it reaches the other target).
Why is that zero a good thing? (it proves the language is load-bearing).

06Mastery & project

You can prove a policy obeys language rather than memorizing one target.

The check that separates real grounding from a lucky-looking policy: flip the word, watch the target flip.

← Act: build the VLA When words have order →

alignment with green:\",round(cg,2))\nprint(\"told RED -> alignment with red: \",round(cr,2))\nprint(\"the two instructions give different actions:\", bool(np.linalg.norm(a_green-a_red)>0.3))\nassert cg>0.9 and cr>0.9 and np.linalg.norm(a_green-a_red)>0.3, \"each instruction must point at its own named target\"\nprint(\"PASS - the instruction, not the geometry, decides the target. The language is load-bearing — the 0%-when-flipped result from our released nano-VLAs.\")","label":"Does it obey? each instruction → its own target"}],"intro":"Flip the instruction and confirm the target flips with it.","key":"vision-language-action/obeys","kind":"python","title":"Does it obey?"}">

PYTHON · NUMPY · IN-BROWSER

Does it obey?

Flip the instruction and confirm the target flips with it.

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