`middle` mouse button does not work in computer use

[rovle]

Summary

Daytona computer use documents middle as a supported mouse button value, but in practice it does not behave as a middle click.

Instead, passing button="middle" appears to silently degrade to a left click in the current X11-backed implementation.

This is primarily a documentation / contract mismatch issue: the public API, SDK docs, and request schema say that middle is valid, but the actual runtime behavior does not honor that contract.

Reproduction

sandbox.computer_use.mouse.click(400, 200, "middle")

Expected behavior

The request should emit a real middle-click event.

Actual behavior

The request does not produce a middle click. In the current implementation it appears to fall back to a left click instead, with no validation error or warning.

Why this is a bug

The public contract explicitly advertises middle as a supported value.

Examples in the codebase currently describe the button as:

• left, right, middle in apps/daemon/pkg/toolbox/computeruse/interface.go
• ('left', 'right', 'middle') in SDK docs and docstrings

That means users are being told to rely on a value that does not work as documented.

Suspected cause

The computer-use plugin forwards the raw button string into the mouse backend without normalizing or validating it.

The backend uses go-vgo/robotgo, which expects "center" for the middle mouse button rather than "middle". Because "middle" is not a recognized value, it misses the mapping and falls back to the default left button behavior.

Impact

• Middle-click workflows cannot be automated reliably
• Users receive no error, so failures are misleading and hard to debug
• The behavior violates documented API / SDK expectations