input.tap

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

With no annotations, the description carries full behavioral burden. It usefully discloses the injection mechanism ('直接注入', no selector parsing) and the long-press threshold hint, but says nothing about coordinate frame (absolute vs normalized), required device state, or what happens on failure.

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?

A single compact sentence with a parenthetical; the core operation is front-loaded and there is no filler. Slightly dense but every clause carries 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 simple primitive with no output schema and no annotations, this covers the essential what and the long-press mechanism, but leaves notable gaps: coordinate reference frame, device-state prerequisites, and error behavior. Adequate but not complete.

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 only 33% (only duration_ms documented, as '>120 视为长按'). The description reinforces duration_ms semantics and implies x/y are raw coordinates, but adds no detail on coordinate system or units to compensate for the undocumented x/y parameters.

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 and resource (raw coordinate tap) and adds scope ('通用层原语：不解析选择器，直接注入'), which meaningfully distinguishes it from selector-based siblings like ui.click/ui.long_click. It stops short of naming the alternative explicitly, but the contrast is clear.

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?

Implies usage context by calling itself a raw-coordinate primitive that bypasses selector parsing, and notes that long-press is achieved by raising duration_ms. However, it never states when to prefer this over ui.click/ui.long_click, nor any exclusions or preconditions.

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