screen_move

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It discloses the environment variable requirement, but it does not explain coordinate semantics (absolute vs. relative), the origin of coordinates, potential side effects, or failure modes. Important behavioral details remain ambiguous.

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 a single sentence that immediately states the action and the key prerequisite. It is appropriately sized for a simple tool, avoids redundancy, and front-loads the essential purpose.

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?

Although the tool is simple, the description and schema together lack essential context such as the coordinate system, whether the move is absolute, and expected error behavior. Given the absence of an output schema and annotations, this is insufficient for an agent to reliably invoke the tool with correct parameters.

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 has two numeric parameters with 0% description coverage, and the description does not clarify what x and y represent. It only indicates that the cursor will be moved, offering no guidance on coordinate interpretation, units, or whether the values are absolute or relative.

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 explicitly states the operation: 'only move the mouse cursor,' which is a specific verb+resource. The prefix 'only' clearly differentiates it from sibling tools like screen_click and screen_drag, making its purpose unambiguous.

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 mentions a required environment variable (VISION_ALLOW_SCREEN_CONTROL=1) but provides no guidance on when to use this tool versus alternatives such as screen_click or screen_drag. No alternative tools are referenced, and no use cases are described, leaving the agent to infer usage from the name alone.

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