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

The description enhances the annotations by adding a proactive safety warning: 'it may update application data.' This explicitly states the functional risk beyond the 'destructiveHint: true' annotation, framing the necessary verification step for the agent.

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 an extremely efficient single sentence. It is front-loaded with the core function and ends with a vital operational caveat, demonstrating zero 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?

Given the high complexity (10 parameters) and the presence of detailed annotations and an exhaustive schema, the description is highly effective at giving the agent the necessary 'why' and 'how' context, even if it doesn't list every possible input parameter.

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?

Since the schema coverage is 100%, the description does not need to explain parameter values. Instead, it provides semantic context by explaining that the parameters serve as 'element ID or semantic selectors,' guiding the agent on the functional purpose of the inputs (e.g., they are pointers to UI elements, not just strings).

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 function: to replace the value of native accessible text fields or editable controls. It specifies the methods of addressing these controls (element ID or semantic selector), providing sufficient clarity while allowing the agent to use the rich input schema to differentiate targeting methods.

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 crucial operational guideline ('Check the target before writing'). However, it does not explicitly state when to use this tool versus similar siblings like 'browser_type' (which simulates keystrokes) or 'ui_set_range_value,' relying on the agent's ability to infer the difference between setting a value and typing.

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