previewapk_tap

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

With no annotations, the description carries the full behavioral burden. It usefully discloses the coordinate model (0..1 resolution-independent fractions) and the session precondition, but says nothing about what a tap does on failure, whether it blocks, timing/rate behavior, or the effect of omitting device.

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-loaded with the action before the coordinate convention and the precondition. No filler, though the third sentence is terse enough to be slightly ambiguous about what 'agent-driven session' means.

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 tap tool with no output schema, the definition covers the action, coordinate system, and one prerequisite. It is still incomplete on the 'device' parameter and on failure/timing behavior, which an agent invoking it repeatedly would need.

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%, so the description must compensate. It does explain the semantics of x and y (fractions of screen, resolution-independent), which is the most error-prone part, but the third parameter 'device' is undocumented in both schema and description.

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+resource ('Tap the screen') that an agent can immediately act on. It does not, however, distinguish itself from the closely named sibling previewapk_tap_text or contrast with previewapk_swipe, so sibling differentiation is left to inference.

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 description supplies one real precondition ('Requires an agent-driven session'), which tells the agent when the tool is callable. It gives no guidance on choosing tap over tap_text or swipe, and no exclusions or alternatives are named.

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