get_screen_info

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

With no annotations, the description carries the full behavioral burden. It does not say whether the tool is read-only, whether it has side effects, what the return format looks like, or what happens if zero or multiple devices are connected; only the returned data categories are listed.

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 short and front-loaded, but the fragmentary phrasing leaves out the action verb and makes it read as a label rather than a complete tool description. It is concise but under-specified.

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 one optional parameter and no output schema, the description should explain device-selection behavior, what is returned and in what form, and how it relates to current_app. It lists the data categories but omits the operational context needed to invoke it confidently.

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 single optional serial parameter is fully described in the schema, including the one-device shortcut. The description adds no parameter meaning beyond that, so the 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 names a clear resource and enumerates what the tool reports: screen size, density, coordinate scale, and foreground app. But it is a noun phrase with no verb, and it does not distinguish this tool from siblings like current_app, which also exposes foreground-app information.

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?

There is no guidance on when to call this tool versus current_app or screenshot, nor on when device selection matters. The description simply states what information is available, leaving the agent to infer usage from the name alone.

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