android_pinch

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

The annotations already declare destructiveHint=true and readOnlyHint=false, so the safety profile is known. The description adds scoping context with 'bounded' and 'around a point', but does not explain side effects, screen limits, or whether this triggers zoom behavior. It does not contradict the annotations, and the added context is modest yet still useful.

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 with zero filler, front-loading the action and its key variants. Every word contributes meaning, making it highly efficient for quick reading.

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?

With 7 parameters, 0% schema coverage, and no output schema, the description is not sufficient for correct invocation. It does not clarify the distinction between x/y and nx/ny, the meaning of amount, or the expected outcome. While the gesture concept is simple, the parameter ambiguity is a significant gap.

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 0%, so the description must compensate, but it only hints at direction and the center point. Parameters nx, ny, amount, and durationMs are left unexplained, and their meaning is not self-evident from names alone. An agent would be uncertain how to set these values correctly for a bounded pinch.

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 states a specific verb ('perform'), a clear resource ('two-finger pinch'), and the direction options ('in or out') around a point. It is easily distinguishable from sibling gesture tools like android_tap, android_swipe, and android_scroll, which do not involve pinching. The 'bounded' qualifier adds useful precision without obscuring the purpose.

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 explicit when-to-use or when-not-to-use guidance is provided, and no alternative tools are named. The use case is implied by the name and phrase 'two-finger pinch', but the description does not explain how this differs from related gestures or in which scenarios it is appropriate. This is adequate but leaves the agent to infer context.

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