screen_drag

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

No annotations are provided, so the description carries the full burden. It discloses the VISION_ALLOW_SCREEN_CONTROL requirement, which is useful, but it does not describe the drag behavior, button handling, coordinate system, or potential side effects.

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 extremely brief—a single sentence with a necessary prerequisite. There is no waste, but it is under-specified relative to the tool's complexity.

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?

With 6 parameters, no output schema, and no annotations, the one-line description is far from complete. It lacks coordinate semantics, return values, button details, and behavioral context.

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 only 17% (only duration has a description). The description adds no meaning to x1, y1, x2, y2, or button, leaving these essential parameters undefined.

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 tool performs a mouse drag operation and includes a specific prerequisite. It is distinguishable from siblings like screen_click and screen_move by the action name, though it does not explicitly differentiate.

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 mentions the required environment variable VISION_ALLOW_SCREEN_CONTROL=1, which is a precondition, but gives no guidance on when to use drag rather than other input tools, nor any exclusions or typical usage scenarios.

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