send_mouse_motion

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

The description adds 'Requires run_interactive' and clarifies no clicking occurs, which is useful context beyond the sparse annotations. However, it doesn't describe return values, failure modes, or whether the movement is instant, leaving a moderate gap.

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 three short sentences, all informative and directly relevant. It is front-loaded with the core action and includes use cases and a prerequisite with no unnecessary words.

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 simple two-parameter tool with a clear purpose and use cases, this is nearly complete. It covers prerequisites and intended scenarios. The only minor omission is what occurs if run_interactive is not active, but this is a shared tool 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 coverage is 100%, with x and y both described as 'viewport pixels.' The description adds no additional parameter meaning beyond what the schema already provides, so baseline 3 is appropriate.

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: 'Move the mouse cursor to specific coordinates without clicking.' This is a specific verb+resource and distinguishes from clicking tools, which is important given siblings like send_mouse_click and send_mouse_drag.

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?

Provides explicit use cases ('hover effects, aiming, and cursor tracking') and a prerequisite ('Requires run_interactive'). It implies exclusions by saying 'without clicking,' but does not explicitly name alternatives like send_mouse_click.

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