android_tap

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

With no annotations present, the description carries the full behavioral burden: it states the tap action, how stale refs are re-resolved, that a screenshot can be returned, and the screenshot's scale behavior. It does not mention side effects or preconditions, but for a UI tap tool the core behavior is disclosed.

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 one-sentence purpose is front-loaded, then a compact Args block covers the parameters without fluff. Every sentence provides operational detail; no repeated or irrelevant information.

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 mutating interaction tool with no output schema, the description is mostly complete: it defines the targeting modes, device default, and screenshot options. A minor gap is that it does not explicitly state that one of ref/text/coordinates is required, which would fully prevent an empty call.

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%, and the description fully compensates by explaining all seven parameters, including the source of ref ('android_ui_dump'), the matching semantics of text (visible text or content-desc), default device behavior, and the screenshot/scale meanings. Each parameter's purpose is concrete with an example.

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 names a concrete action ('Tap the screen') and enumerates the three supported targeting modes (ref, text, coordinates), making the tool's resource and behavior unambiguous. It is clearly distinguishable from sibling input tools like android_swipe or android_type.

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 gives practical selection guidance among modes (ref from a dump, text/content-desc, or raw coordinates when the hierarchy exposes nothing tappable). It does not explicitly contrast this tool with swipe/type/key siblings, so a small exclusion-based guidance gap remains.

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