tap

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

With no annotations present, the description must carry the behavioral load; it does disclose that element ids are only valid relative to the last read_screen (a staleness constraint) and that coordinates are in screen pixels. It says nothing about what happens after the tap (navigation/UI change), failure modes for invalid ids, or timing, which would matter for an interaction tool.

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?

One front-loaded sentence that names the action and both targeting modes with zero filler. Nothing is buried or repeated.

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 simple, zero-required-param interaction tool this covers the essentials, but with no output schema and no annotations the description leaves open what a tap returns (success/failure), whether it awaits a UI transition, and how conflicting element + coordinate inputs are resolved.

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 100%, so all three parameters are already documented with units and provenance in the schema itself. The description restates the same semantics (element id source, pixels) without adding new meaning such as precedence when both element and x/y are supplied, which remains undefined.

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 both accepted targets — an element id or pixel coordinates — so the resource and input modes are unambiguous. It stops short of differentiating itself from close siblings like long_press, swipe, or press, which an agent could confuse with a plain tap.

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?

The phrase "by id from the last read_screen" implies the workflow prerequisite (read the screen first) and signals the two alternative targeting modes. There is no explicit when-not guidance, e.g. that long_press should be used for hold gestures or that coordinates are the fallback when elements aren't exposed.

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