appium_mobile_device_info

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

Annotations already carry the readOnlyHint=true safety profile, so the description only needs to add behavioral context, and it does add some: the 'single call' efficiency trait and the cross-platform scope ('Works on both iOS and Android'). However, it does not disclose edge behaviors like session requirements, error cases, or permission needs; these are not critical given the read-only profile but prevent a higher score.

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?

Three short sentences with the core purpose front-loaded. The platform note ('Works on both iOS and Android') adds genuine value, while the action-parameter sentence is mildly redundant with the schema but still concise. No wasted words overall.

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 low-complexity read-only tool (one required param, no output schema), the package is complete: the description covers the purpose and platform scope, and the schema fully documents parameter semantics including return-value descriptions via the action enum. The only notable gap is the absence of sibling-selection guidance, which is already counted under usage guidelines.

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%, and the schema already documents each parameter in detail, including the enum meanings for action ('info' returns device model/OS/locale/etc., 'battery' returns battery level and charging state, 'time' returns current device time) and the sessionId fallback behavior. The description's 'Use the action parameter' line merely restates the schema, adding no semantic value beyond the baseline.

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 names a specific verb ('Get') and resource ('device information, battery status, or current device time'), and explicitly enumerates the three retrievable data types. This clearly distinguishes it from siblings like appium_mobile_device_control and select_device, which cover control and selection rather than info retrieval.

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?

Usage is implied rather than explicit: an agent can infer to use this when device info, battery, or time is needed, but there is no when-not-to-use guidance or alternative routing. The sentence 'Use the action parameter to select which data to retrieve' explains in-tool parameter behavior, not tool selection. With 30+ siblings, explicit exclusion guidance would have helped.

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