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

No annotations are present, so the description carries the behavioral disclosure burden. It usefully reveals the non-obvious relationship between device_info output and tap/swipe coordinate semantics, including that no scaling is needed. However, it does not explicitly state read-only behavior, response format, or whether screen-size information is always available.

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 and each earns its place: the first states the tool's purpose, and the second delivers a high-value coordinate-system caveat. There is no filler, repetition of schema data, or unnecessary background.

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 one-parameter read-only info tool, the schema covers the invocation requirement, and the coordinate note anticipates the main downstream use case. However, there is no output schema and 'detailed info' leaves the returned fields vague, so the agent cannot know precisely what information to expect.

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 sole parameter, udid, is fully documented in the schema with 100% coverage, so the description does not need to repeat field-level semantics. It adds no extra parameter meaning beyond what the schema already provides, matching the baseline for high schema coverage.

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?

Opens with a clear verb and object: 'Get detailed info about a device.' The phrase 'including physical screen size' gives concrete scope. It does not explicitly distinguish itself from sibling tools like device_list, device_screen, or ios_device_info, so it stops short of full sibling differentiation.

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 coordinate-system note tells agents that device_tap and device_swipe use physical pixels, but it never states when to prefer device_info over alternatives or when it should not be used. No exclusions or sibling routing are provided, leaving the agent to infer relevance.

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