tap_element

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

No annotations are provided, so the description carries the full burden. It says the tool taps an element by index, but it does not disclose side effects, required permissions or accessibility state, invalid-index behavior, stale-list risks, or whether the tap is immediate.

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 description is a single front-loaded sentence with no unnecessary wording. It is appropriately sized for a one-parameter action tool.

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 one-parameter action tool, the description identifies the source of the index, which is the essential call context. However, with no annotations or output schema, it omits prerequisites such as fetching the latest UI elements, invalid-index handling, and outcome reporting.

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 add meaning for the index parameter. It usefully explains that index refers to an element number from the latest screenshot or get_ui_elements list, but it leaves open zero-based versus one-based indexing, valid range, ordering, and what happens if the list has changed.

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 states a specific verb, resource, and source: it taps an element by index from the latest screenshot or get_ui_elements list. This distinguishes it from coordinate-based tap and from sibling tools like get_ui_elements or screenshot.

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 implies the tool should be used after obtaining the latest screenshot or get_ui_elements list, but it does not explicitly state when to use this instead of tap, voice_tap, long_press, or other interaction tools. The usage context is inferable but not fully guided.

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