Tap a normalized point

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

No annotations are provided, so the description carries the burden. It describes the normalized coordinate mapping, which is the main behavioral trait, but it doesn't mention possible side effects, device focus requirements, or error behaviors. For a simple tap, this is adequate but not rich.

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?

Two sentences, front-loaded with the action and coordinate definition. Every phrase adds useful context, with no wasted words.

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 tool with only 2 parameters and no output schema, the description plus schema gives the agent enough to call it correctly. Slightly incomplete in that it omits outcome/error expectations, but this is a very simple tap action.

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 already describes x and y as fractions of screen width/height; the description adds the valuable mapping of (0,0)=top-left, (1,1)=bottom-right and the screenshot-scaling motivation, meaning beyond the schema's min/max bounds.

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 clear verb and resource: taps at a normalized position. Defines the coordinate system explicitly and explains the scaling context, distinguishing it from the likely absolute-coordinate sibling '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?

Provides a clear context: 'useful when tapping from a screenshot without knowing the scale'. However, it does not explicitly name the alternative tool or say when not to use this one, so it lacks the full when/when-not guidance.

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