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

With no annotations, the description carries the full transparency burden. It discloses that the tool scrolls the element into view, dispatches a mouseMoved to its center, sets isTrusted:false on iOS, and throws if the target does not resolve. These details give the agent concrete expectations about side effects and failure modes.

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?

Four short sentences cover action, use case, iOS behavior, and error condition without filler. Each sentence contributes operational value, resulting in a dense but well-structured description.

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?

Despite no output schema, the description conveys the essential behavior, platform support, error behavior, and relationship to webpage_click. The tool is a simple hover action with minimal return expectations, so the description is complete for an agent to use it correctly.

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?

Input schema has 100% parameter descriptions, so baseline is 3. The description adds context about ref usage and platform auto-detection, but the schema already explains ref/selector relationships and optional parameters. No significant added meaning beyond schema.

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 opens with a specific verb phrase 'Hover the pointer over an element in the device browser page' and specifies targeting by CSS selector or ref. It explicitly ties usage to revealing hover menus/tooltips before webpage_click, distinguishing it from click and scroll siblings.

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 says 'use it to reveal hover menus/tooltips before webpage_click,' providing clear when-to-use and a direct connection to a sibling tool. The guidance is explicit about the operation's purpose and sequencing relative to clicks.

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