left_click

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

With no annotations, the description carries the full burden. It only states 'left-click' and 'screenshot space', omitting details like whether the mouse moves, behavior for out-of-bounds coordinates, or effects of the background parameter (which is detailed in the schema but not the description).

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 sentence that is front-loaded with the action. It is efficient but too brief to provide needed context, given the complexity of coordinate-based clicks.

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 3 parameters, no output schema, and no annotations, the description is inadequate. It omits crucial behavioral details such as coordinate system origin, click simulation behavior, and how background mode works. The schema provides more detail for the background parameter, but the tool description itself is incomplete.

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?

Schema description coverage is low (33%). The description adds meaning to x and y by specifying coordinate space, but does not explain the background parameter or their types. This partially compensates for the low coverage but is not comprehensive.

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 it performs a left-click at given coordinates and specifies 'in screenshot space', which adds context. It implicitly distinguishes from right_click and double_click via the name, but does not explicitly differentiate from ax_click or other click tools.

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 sibling tools like ax_click or click_mark. The description does not indicate prerequisites, context, or exclusions.

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