adb_screen_size

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

DESCRIPTION without annotations: The description discloses what the tool returns and its utility, but does not mention behavioral aspects such as how the data is obtained (e.g., via ADB commands), whether it requires an active device connection, or any limitations (e.g., might not work on all devices). It leaves some behavioral uncertainties.

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 concise and well-structured: it starts with the purpose, then details the outputs, and ends with a use case. Every sentence adds value, and there is no unnecessary information.

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 low complexity (one optional parameter, no output schema), the description is largely complete. It covers purpose, outputs, and a use case. Minor omissions include the fact that the device parameter is optional and defaults to the connected device, but overall it is adequate.

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% as the only parameter (device) has a clear description in the input schema. The tool description adds no additional meaning beyond what the schema already provides, so the baseline 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 the tool gets screen resolution and display density, specifying the exact outputs (width, height, DPI) and a use case (calculating tap/swipe coordinates). However, it does not distinguish itself from sibling tools like adb_screen or adb_screen_state, which may also provide screen-related 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?

The description implies the tool is useful for coordinate calculations and UI layout understanding, but it provides no explicit guidance on when to use it versus alternatives or any when-not scenarios. The usage context is inferred rather than stated.

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