ui_read_tree

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

No annotations are provided, so the description bears the full burden. It does disclose a key behavioral trait: the tree is 'COMPACT' and limited to 'labeled + interactive elements', which helps the agent know not to expect all nodes. However, it lacks details on whether accessibility permissions are required, how the tree is structured, or if there are any latency implications.

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 a single, front-loaded sentence that immediately states the primary purpose. It uses no filler words and every element ('COMPACT', 'labeled + interactive') adds value. Although truncated in the prompt, the provided text is highly concise.

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?

The tool lacks an output schema and annotations, so the description should clarify the return format, but it only says 'accessibility tree' without specifying whether it is a string, JSON, or a visual representation. It also omits prerequisites like 'app must be running' or accessibility permissions. Given the zero-parameter simplicity, the description is incomplete for an agent to confidently use the result.

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 tool has zero parameters, and the input schema is empty, so there are no parameter semantics to clarify. Per the rubric, a baseline of 4 is appropriate when there are no parameters; no additional description is needed.

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 returns a 'COMPACT accessibility tree' of a running native app's 'labeled + interactive elements', using a specific verb ('Returns') and a specific resource. This distinguishes it from siblings like ui_get_element and ui_find_element, which target individual elements rather than the whole tree.

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?

No guidance is provided on when to use this tool versus alternatives. It does not mention alternatives or conditions such as 'use this to get the full UI structure' or 'prefer ui_find_element for locating a single element'. The description is purely functional with no contextual placement among the many UI-related sibling tools.

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