device_tap

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

With no annotations provided, the description carries the full burden. It discloses the low-level risk and the Android auto-scaling behavior, which are useful. It does not describe return values, failure modes, or side effects beyond the tap itself, so some behavioral context is still missing.

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?

Three short sentences front-load the warning and the primary alternative, then pack coordinate guidance and Android-specific behavior into the rest. Every sentence earns its place with no repetition or fluff.

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 low-level tap tool, the description gives the crucial coordinate-source rule and platform scaling detail. It does not mention what the tool returns or how verify behaves, but the schema covers verify, and a simple tap tool does not need a longer narrative to be callable 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?

Schema coverage is 67%, and the description adds essential meaning to x and y by specifying they come from the physical screenshot's originalWidth/originalHeight. It also adds platform-specific scaling context for Android. The remaining parameters are adequately explained in the schema.

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 and resource: 'Tap at raw screen coordinates'. It also distinguishes itself from the sibling tap_on_element by explicitly labeling itself as low-level and less reliable, so an agent can tell them apart immediately.

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?

It clearly steers agents toward tap_on_element when reliability matters, and supplies the coordinate source ('physical screenshot originalWidth/originalHeight'). The guidance is practical and directional, though it does not list exhaustive when-not-to-use scenarios.

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