Inspect Android UI

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is clear. The description adds context about the output being a 'compact UI Automator hierarchy' with 'node IDs', but does not elaborate on behavioral traits like performance or limitations. This adds modest value beyond annotations.

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?

Two sentences that are front-loaded with the action and include a practical follow-up use case. Every word earns its place; no waste.

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, the description should clarify the return format (e.g., XML string containing node IDs). It mentions 'snapshot and node IDs' but does not specify the data structure, leaving ambiguity for the agent. It covers the basic purpose and use case but lacks detail on the output.

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 coverage is 100% with a well-described optional 'serial' parameter. The description does not add any additional meaning beyond the schema, so baseline score of 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 captures a compact UI Automator hierarchy and specifies its use for safe node-targeted taps using snapshot and node IDs, effectively distinguishing it from siblings like android_take_screenshot (image capture) and android_tap (action).

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 implies usage for obtaining UI structure before tapping ('Use its snapshot and node IDs for safe node-targeted taps'), providing clear context. However, it does not explicitly state when not to use this tool or how it differs from alternatives like android_take_screenshot for visual inspection.

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