describe_ui

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It effectively describes the tool's behavior: it returns a JSON tree with frame data, operates on visible elements, and is intended for automation accuracy. However, it lacks details on potential errors, performance implications, or data freshness, leaving some behavioral aspects unspecified.

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 highly concise and well-structured, using two sentences that front-load key information: the core functionality and usage guidelines. Every sentence adds value without redundancy, making it efficient and easy to parse for an AI agent.

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 (UI hierarchy analysis) and lack of annotations or output schema, the description does a good job covering purpose, usage, and return format. However, it misses details on the parameter and potential edge cases (e.g., handling invisible elements), leaving minor gaps in completeness for automation scenarios.

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 0% description coverage, but the description does not mention the 'simulatorUuid' parameter at all. While it implies context about simulators through usage guidance, it fails to explain what this parameter means or how to obtain it. With low schema coverage, the description does not compensate adequately, resulting in a baseline score.

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's purpose with specific verbs ('Gets entire view hierarchy') and resources ('with precise frame coordinates for all visible elements'). It distinguishes itself from sibling tools like 'screenshot' by emphasizing coordinate accuracy over visual guessing, making its role in UI automation explicit.

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 provides explicit guidance on when to use this tool ('before UI interactions or after layout changes') and when not to ('do NOT guess coordinates from screenshots'). It implicitly suggests alternatives like screenshot-based methods but clearly directs users to this tool for accurate automation, offering strong contextual usage rules.

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