mouse_drag

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations only state readOnly=false, destructive=false, and idempotent=false, which are minimal. The description adds meaningful behavioral context by disclosing the VM lock state and the need to unlock. It does not contradict annotations, but could also mention whether the mouse button is released at the end.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two sentences, with the main action front-loaded and the lock reminder as a secondary note. Every word contributes value, with no redundant information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description covers the primary action and the lock requirement, but lacks details about how steps, duration_ms, or button affect the drag behavior. It also does not state whether the button is released after the drag. Given the tool's moderate complexity and minimal annotations, this is adequate but with clear gaps.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema only describes the four coordinate parameters (from_x, from_y, to_x, to_y) with 'Zero-based physical screen coordinate.' The description does not add meaning for the undocumented parameters steps, button, or duration_ms, leaving their effects unclear. With 57% schema coverage, some compensation from the description was expected but not provided.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action ('Drag between exact pixel coordinates while holding the selected mouse button'), identifying both the operation and its resource. This distinguishes it from sibling tools like mouse_move, mouse_click, and mouse_down/up, which have different behaviors.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides clear context by noting that the VM remains locked and instructs to call vm_unlock when finished. However, it does not explicitly mention when to use this tool over alternatives like mouse_move or input_batch, or any exclusions.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.