native-view-at-point

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

With no annotations, the description carries the full burden. It discloses the return format (status + view with class, frames, identifier, label, layer name, ancestor chain, subviews on request), the coordinate system (raw points, not normalized), and detailed error-handling for statuses (restart_required, service_stale, connect_pending, init_failed) and failure modes (system apps rejected). No contradictions with annotations since none are present.

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 long but well-structured: it opens with the core purpose, then contrasts with a sibling, gives a use case, describes return structure, and concludes with status handling. Every paragraph covers a distinct aspect and includes necessary operational details. It could be slightly trimmed but remains efficient given the tool's complexity.

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 the tool's complexity (10 parameters, 4 required) and the absence of an output schema, the description is exceptionally complete. It covers the return value structure, all expected statuses with recovery steps, coordinate system specifics, and Edge cases (system app rejection). It leaves no major gaps for an agent to successfully use the tool.

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 provides 100% coverage of all 10 parameters, including descriptions for x/y coordinates and field lists. The description adds a warning about raw coordinates and clarifies default behavior (e.g., includeAncestors defaults true), but these are already in the schema. It does not significantly add value beyond what the schema documents, so the baseline 3 is appropriate.

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 it inspects the deepest visible UIView at a raw native window point, and explicitly contrasts with native-user-interactable-view-at-point, distinguishing it as answering 'what is visually here?' rather than 'what would receive the touch?'. This makes the purpose specific and distinct from siblings.

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 provides explicit when-to-use guidance: 'Use when a screenshot shows something the accessibility tree does not name — an unlabeled icon, a decorative overlay, a custom-drawn cell'. It also names the sibling alternative and explains the difference, fulfilling the when/when-not requirement fully.

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