Inspect Phone Link UI Tree

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

Annotations already indicate readOnlyHint=true, idempotentHint=true, and destructiveHint=false, and the description does not contradict them. It adds useful behavioral context beyond the annotations: it is a diagnostic dump, the depth parameter trades completeness for speed ('Higher = more elements but slower'), and it returns a JSON structure. This is sufficient for a non-destructive inspection tool.

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 well-structured with a one-line summary, a use-case paragraph, and clearly separated Args/Returns sections. It is slightly longer than necessary because the Args and Returns sections echo schema and output details, but each part is organized and front-loaded with the core purpose. No filler content is present.

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 tool with no output schema, the description provides a return type sketch with element_count, window_name, and elements fields, plus parameter bounds and defaults. It gives an agent everything needed to call the tool correctly, understand what it returns, and decide when it is appropriate, especially with the annotations covering the read-only/idempotent nature.

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 schema already documents both parameters thoroughly. The description's Args section mostly repeats the schema (max_depth, filter_control_type) with only a minor addition about depth affecting speed. This matches the baseline of 3 for high schema coverage; the description adds little new parameter meaning.

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 opens with a specific verb and resource: 'dumps the Phone Link UI automation tree as JSON'. It also explains the tool is a debug tool for discovering UI element names, automation IDs, control types, and bounding rectangles, which clearly distinguishes it from the data-retrieval and action siblings like phonelink_get_messages and phonelink_send_message.

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 explicitly states when to use the tool: 'Use this to discover UI element names, automation IDs, control types, and bounding rectangles' and frames it as 'Helpful for troubleshooting when other tools can't find expected elements.' This provides clear context, though it does not explicitly name alternatives or state when not to use it.

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