Read the mouse position

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so safety is covered. The description adds genuine value by disclosing that two distinct cursor contexts exist (virtual browser vs real Windows), which the annotations do not convey. It does not explain which context is reported or how the two are disambiguated.

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?

A single front-loaded sentence with no filler. Every clause (virtual browser cursor, real Windows cursor) carries information the agent would not otherwise have.

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 an output schema present and annotations covering the safety profile, the description needn't explain return values. It is nearly complete; the only gap is not clarifying how the virtual vs real cursor distinction is resolved or under what configuration each applies.

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 tool takes zero parameters, so there is no parameter semantics to document; the baseline of 4 applies. The description correctly avoids inventing parameters.

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?

States a specific verb (Read) and resource (cursor position), and clarifies the scope by naming both possible targets: the virtual browser cursor or the real Windows cursor. An agent can distinguish this from mouse_move or mouse_click without consulting schemas.

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 implies when to use it (when you need the current pointer coordinates) but gives no explicit routing guidance against siblings such as mouse_status or computer_observe, which could plausibly overlap. No prerequisites or exclusions are stated, leaving selection partly to inference.

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