mouse_drag

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

The annotations are sparse and do not mention lock behavior, so the description adds valuable behavioral context by warning that the VM remains locked by this session and instructing the agent to call vm_unlock afterward. It does not detail whether the button is released at the end of the drag, but the core side effect is disclosed.

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 compact and well-structured: the first sentence states the operation, and the second sentence conveys the critical lock state and required follow-up. There is no redundant wording or repetition of schema details.

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?

For a tool with 8 parameters and no output schema, the description covers the essential behavior, the coordinate-based nature of the drag, and the important lock side effect. It leaves some minor gaps such as whether the mouse button is released at the end and what the command returns, but the provided information is sufficient for an agent to invoke it correctly in most cases.

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?

Schema description coverage is 63%, and the description adds only marginal semantic value beyond the schema: 'exact pixel coordinates' maps to from_x/from_y/to_x/to_y, and 'selected mouse button' maps to the button enum. It does not explain the optional parameters steps or duration_ms, which are only documented by defaults and ranges in the schema.

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 opens with a specific action verb and resource: 'Drag between exact pixel coordinates while holding the selected mouse button.' This clearly identifies the tool as a mouse drag operation and implicitly distinguishes it from sibling tools like mouse_move or mouse_click by emphasizing the held button during movement.

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?

It provides clear context for when to use the tool: dragging between exact pixel coordinates with a chosen mouse button. It also gives an explicit follow-up directive: the VM remains locked and vm_unlock should be called when finished. However, it does not explicitly name alternatives or state when not to use it.

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