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 discloses the dependency on get_elements() and the action of tapping, but does not mention error handling, out-of-bounds behavior, or UI wait conditions. This is adequate for a simple action but could be more transparent.

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 two sentences, front-loaded with the action, and contains no fluff. Every sentence earns its place by explaining both the action and the prerequisite.

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 action with an output schema present, the description covers the core workflow (call get_elements, then tap by index). It lacks details about edge cases and the device parameter, but is largely complete for its simplicity.

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 explains that 'idx' comes from get_elements(), giving some meaning, but the required 'device' parameter is entirely unexplained, leaving a significant gap for the agent.

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 clearly states the tool taps a UI element by its index from get_elements(), using a specific verb and resource. It distinguishes itself from sibling tools like 'tap' by specifying the index-based method.

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 explicitly instructs the user to call get_elements() first to obtain indices, providing a clear prerequisite. However, it does not explicitly contrast with alternative tapping tools like 'tap' (which may use coordinates), so it lacks explicit exclusions.

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