adb_screen_size

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

No annotations are provided, so the description carries the full burden. It states that the tool returns specific values (width, height, DPI) but does not disclose whether it is read-only or requires any specific permissions. Given the simple read nature, the description is adequate but could explicitly state it has no side effects.

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, directly stating the purpose and use case. It is front-loaded and efficient, but could be slightly more structured with bullet points for return values.

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?

Despite having no output schema, the description fully explains what is returned (width, height, DPI) and the context of use. The tool is simple with one optional parameter, and the description covers all necessary aspects for an agent to use it correctly.

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 only parameter 'device' is already described in the schema with 'Device serial'. The description does not add additional meaning beyond the schema, so it meets the baseline for schema coverage at 100%.

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 it retrieves screen resolution and display density, specifying the exact output fields (width, height, DPI). It distinguishes from sibling tools like adb_screencap or adb_screen_state by focusing on dimensions.

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?

It provides a clear use case (calculating tap/swipe coordinates and understanding UI layout) but does not explicitly mention when not to use it or compare to alternatives. The use case is helpful, but more guidance would improve it.

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