ui_click_at

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

Beyond the single annotation (openWorldHint: false), the description reveals that the click goes to the center of the rectangle using the formula x = (left + right) / 2, y = (top + bottom) / 2. This adds meaningful behavioral context not present in annotations or schema.

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 extremely concise with no wasted words. It front-loads the purpose, then provides usage context, coordinate calculation, and parameter list in a structured format. Every sentence is necessary and earns its place.

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 tool's simplicity (no output schema, no complex parameters), the description covers the essential use case, coordinate calculation, and parameter meaning. It does not discuss error behavior or return values, but those are likely obvious for a click action.

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 labels the parameters as 'Screen X coordinate' and 'Screen Y coordinate', which adds a bit of meaning beyond the schema's title fields. However, with 0% schema description coverage and only 2 parameters, more detail would have been beneficial, such as coordinate range or behavior outside bounds. The center calculation is behavioral, not strictly parameter semantics.

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 verb 'click' and the resource 'absolute screen coordinates'. It distinguishes itself from sibling tools like ui_click and ui_click_annotated by specifying that it uses coordinates obtained from ui_get_window_tree rectangle data.

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 explicitly says to use the tool with ui_get_window_tree rectangle data when element search fails, providing clear context for when to use it. It does not mention when not to use it or alternative tools, but the guidance is sufficient.

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