Tap

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

Annotations declare read-only/destructive hints; description adds crucial behavioral details: 'Returns position, selector, and bounding box' discloses return structure (compensating for missing output_schema) and confirms this is a locator utility rather than an interaction tool.

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?

Three sentences, zero waste: (1) Core action, (2) Return values, (3) Usage context. Front-loaded with essential verb, no redundant 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?

Given 2 simple params, read-only annotations, and no output schema, the description covers the critical gaps by disclosing return values and usage patterns. Would need parameter documentation to be fully complete.

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?

With 0% schema description coverage, the description implies 'query' is the visible text string via 'Find elements by visible text', but fails to document the optional 'role' parameter (likely ARIA role filtering). Baseline adequate but incomplete compensation for schema 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?

Specific verb-resource combination ('Find elements by visible text') clearly states the core function. Distinct from sibling inspect_element (which likely uses selectors) by specifying the 'visible text' search 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?

Explicitly states workflow: 'Use before click/type to verify the target exists' — clear when-to-use with specific siblings (tap_click, tap_type). Lacks explicit 'when not to use' (e.g., if selector already known) but provides strong implicit guidance.

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