tap_element

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

With no annotations, the description carries the full burden. It states the action (tap) and dependency on element IDs from other tools, but does not disclose behavioral details such as whether the tap is a single tap, if it waits for element visibility, or side effects like triggering events. The behavior is somewhat obvious but not fully 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-loads the core action, and contains no redundant information. Every word earns its place.

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 tool, the description covers the primary task and source of element IDs, but omits explanations of optional parameters (maxDepth, maxNodes) and sessionId. It also lacks details on return values or error conditions, leaving gaps for an agent to infer.

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?

The input schema has 4 parameters (sessionId, elementId, maxDepth, maxNodes) with 0% schema description coverage. The description only mentions elementId conceptually and does not explain the purpose of sessionId, maxDepth, or maxNodes. It fails to add meaning beyond the raw schema.

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 verb ('tap'), resource ('visible element'), and method ('by element id from get_visible_elements/get_ui_tree'). It also distinguishes from sibling tools by noting it's a preferred fallback before coordinate tapping.

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?

The description explicitly advises using this tool as a preferred fallback before coordinate tapping, providing clear guidance on when to use it. However, it does not specify scenarios where this tool should not be used or alternative methods.

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