tap

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

With no annotations, the description carries the full burden. It discloses that x/y are ignored when text is given, and that ambiguous matches result in no tap and a list of matches. These are important behavioral traits. It doesn't cover potential errors or prerequisites, but the provided details are valuable.

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 well-organized: a clear purpose statement, a preference note, and a compact Args section. It is front-loaded with the core function and the preference, and every sentence adds value without redundancy.

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?

The description covers all parameters and key behaviors, and an output schema exists (so return format is handled). It does not mention error conditions or prerequisites (e.g., device state), but for a simple tap operation, the provided information is sufficient for correct invocation.

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 0%, so the description is the sole source of parameter meaning. It explains x/y as device coordinates (ignored when text is present), text as matching text/content description/resource id, and serial for multi-device scenarios. This fully compensates for the schema's bare types.

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 tool's action ('Tap the screen') and specifies two modes: coordinate-based and text-based. It distinguishes itself from siblings like swipe, input_text, and press_key by focusing specifically on tapping, and the text/coordinate distinction adds specificity.

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?

Explicitly instructs to prefer 'text' for robustness against layout changes, and explains when to fall back to coordinates (when multiple elements match). This provides clear decision-making guidance for the agent, though it doesn't contrast with alternative tools, it fully covers the internal choice.

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