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 behavioral burden. It discloses that it taps the center, uses index to select among multiple matches, and returns the matched element plus tap point, but it does not describe failure behavior, side effects, permissions, or multi-device handling.

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 tightly written sentences with the core behavior and return value front-loaded. Every sentence adds useful information with no filler.

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?

An output schema exists, so return values need not be fully explained. However, for a six-parameter action tool with no annotations and 0% schema coverage, the description should clarify exact matching, serial/device selection, and failure cases, which it does not.

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 for all six parameters. It explains text, resource_id, content_desc, and index, but leaves exact and serial unexplained, leaving meaningful gaps.

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: find an element by text/resource_id/content_desc and tap its center. It clearly distinguishes from a bare coordinate tap by naming selectors, but it does not explicitly contrast with siblings like tap or find_elements.

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?

Usage is implied by the selector-based tap behavior, but there is no explicit guidance on when to choose this over tap, find_elements, or long_press. It also omits any prerequisites such as device selection or match requirements.

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