mobile_screenshot

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

Annotations are all false, so the description must convey behavior. It mentions saving a screenshot and returning a path, which is clear. However, it does not detail file format, naming conventions, or side effects beyond saving.

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 concise sentences with no wasted words. Purpose and usage are front-loaded.

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 the tool's simplicity (no params, no output schema), the description is largely complete. It could be slightly improved by clarifying what 'MobileNAV' is or the expected path format, but it is sufficient for basic selection.

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 no parameters and schema coverage is 100% trivial. The description adds no parameter details but this is acceptable; baseline for 0 parameters is 4.

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 verb ('Save') and resource ('MobileNAV screenshot'), and specifies the return value ('path'). It distinguishes from sibling tools like browser_screenshot and mobile_observe by targeting MobileNAV.

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 phrase 'Use only for visual evidence' implies a specific use case, but it does not explicitly state when not to use the tool or suggest alternatives from the sibling list.

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