ui_double_tap

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 a meaningful caveat—without the on-phone server a slow phone may interpret the action as two single taps—but it does not describe side effects, permissions, or response behavior.

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 primary action and targeting modes, and adds a relevant limitation without unnecessary detail. Every sentence contributes.

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 9-parameter optional UI action with full schema coverage and no output schema, the description is mostly complete: it explains the two targeting approaches and first-match behavior. A minor gap is that it does not clarify how the selector parameters interact or which takes precedence.

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 100%, so the per-parameter schema already documents all nine parameters. The description only adds that coordinates or a first-match selector may be used, without clarifying precedence or combinations among rid, desc, text, label_re, desc_contains, and text_contains.

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 action (double-tap) and two targeting modes: coordinates or the first element matching a selector. It adds a concrete example (zoom in an image or PDF preview), though it does not explicitly distinguish itself from the sibling ui_tap.

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 through the zoom example and the coordinate/selector targeting methods, but there is no explicit guidance on when to choose this over ui_tap or how to choose among the many optional selector parameters. The caveat about slow phones is useful context but not a when-to-use rule.

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