mouse_scroll

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

Beyond the annotations, the description discloses that guest wheel support is required and that the VM lock remains held after the call, necessitating a subsequent vm_unlock. These are important behavioral traits not captured by the readOnlyHint or destructiveHint flags.

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?

Two sentences front-load the core action, then add necessary prerequisites and lock guidance. Every sentence adds value with no wasted 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 input action with no output schema, the description covers the action, prerequisites, and required follow-up unlock. It does not need to explain return values, and the input schema covers coordinate bounds.

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 description mentions 'optional coordinates' and 'mouse-wheel delta' which loosely maps to the parameters, but it does not clarify the meaning of delta (e.g., units or sign). The schema already describes x and y as zero-based physical screen coordinates, so the description adds little beyond that. With delta's schema description missing, the description leaves its semantics vague.

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: 'Send a mouse-wheel delta at optional coordinates.' This specific verb+resource combination distinguishes it from sibling mouse tools like mouse_move (moving the cursor) and mouse_click (clicking). It also mentions optional coordinates, which adds precision.

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 a prerequisite ('Requires guest wheel support') and a post-condition ('VM remains locked by this session; call vm_unlock when finished'). This gives context for when and how to use the tool safely, though it does not explicitly compare with 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.