ui_type

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

With no annotations, the description carries full burden for behavioral disclosure. It discloses the optional focusing step but is silent on error behaviors, support for special keys, input validation, or what happens if no control is focused. Additionally, it references 'element_ref' as an input, but the schema defines no parameters, creating inconsistency that undermines transparency.

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 a single sentence and efficiently conveys the core action. However, the mention of 'element_ref' without schema backing clutters the clarity. It earns a slight penalty due to this ambiguity but remains relatively concise.

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 tool with no annotations, no output schema, and an empty input schema, the description should be more comprehensive. It lacks explanation of return values, input format for text, error conditions, and the nature of the focused control. Critical details are missing, making the tool hard to use 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?

The schema has zero parameters (100% coverage), so baseline is 3. The description adds little positive meaning—it mentions 'element_ref' which does not appear in the schema, potentially misleading the agent. It does not clarify what text to type or how to specify it, which is essential for a typing tool.

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 ('types text') and resource ('focused control'), and mentions an optional preliminary focus step. However, it does not differentiate from sibling tools like chrome_type, safari_type, or web_type, which also type text. The lack of distinction limits clarity for an agent deciding between them.

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?

No guidance is provided on when to use this tool versus alternatives (e.g., chrome_type, ui_keystroke). The description does not specify prerequisites, such as requiring a focused control, or mention cases where another tool should be preferred. This leaves the agent without decision support.

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