get_ui_tree

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 output content, coordinate units, and the reliability caveat ('ground truth where apps expose it'). It does not explicitly state it is read-only or mention permission requirements, but for a read-like tool this is strong.

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-loaded with the core purpose and output format, with no unnecessary detail. Every clause adds value.

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 no output schema and no annotations, the description covers purpose, app parameter semantics, output contents, and a fallback alternative. It does not document max_depth or return formatting details, but these are largely inferable from the schema and tool name, making it complete enough for selection and invocation.

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 description clarifies the app parameter by stating it defaults to the frontmost app, matching the schema default. However, max_depth is never mentioned, and schema description coverage is 0%, so the description only partially compensates for the lack of parameter documentation.

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 what the tool does: returns an accessibility tree for an app with roles, titles, values, and clickable regions in points. It also distinguishes itself from sibling find_text by noting the appropriate tool for cases where accessibility data is not exposed.

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 explicitly says to use find_text when apps don't expose the accessibility tree, providing a clear alternative and exclusion condition. It also notes that the app parameter is optional and defaults to the frontmost app.

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