tap

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

No annotations are provided, so the description carries the full behavioral burden. It does not disclose that this injects a synthetic input event (a mutating action), whether it blocks until the tap completes, what happens on out-of-bounds coordinates or a disconnected device, or any failure/return behavior.

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 nine-word sentence with zero filler, and the distinguishing detail (absolute pixel coordinates) is front-loaded rather than buried.

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 three-parameter tool with no output schema, the definition is minimally adequate but omits the device-selection constraint (only covered in the schema for the optional device param) and any hint about coordinate validity or post-tap effects.

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 coverage is only 33% – x and y have no descriptions at all, so the description must compensate. 'Absolute pixel coordinates' does add real meaning for x/y (pixel units, absolute rather than normalized or relative), but gives no ranges, origin reference, or screen-size dependency, leaving the semantics partially documented.

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?

States a specific verb (tap) and target (the screen) plus the coordinate system (absolute pixels), which is enough to distinguish it from gesture siblings like swipe and scroll. It stops short of naming tap_text, the closest sibling, so the agent must infer the text-vs-pixel split itself.

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?

Usage is only implied: 'absolute pixel coordinates' hints that this is for when you already know exact coordinates, and tap_text is the obvious alternative when you don't, but neither the alternative nor the condition is stated. No exclusions, prerequisites, or coordinate-origin guidance are given.

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