Switch Display

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

Annotations already signal that this is not read-only and is marked destructive. The description adds the useful context that the tool's effect is scoped to screenshots. It does not disclose persistence or side effects beyond that, but for a simple one-parameter selector this is acceptable.

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 a single, front-loaded sentence with no filler or redundancy. It says exactly what the tool does and nothing more.

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, one fully documented parameter, no output schema, and annotations covering safety, the description is nearly complete. It could optionally reference list_displays for discovering valid indices or clarify whether the selection persists, but these are not essential for correct invocation.

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 coverage is 100% and the 'index' parameter is already described as a zero-based display index. The description adds no additional parameter-level detail, so the baseline score of 3 applies.

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 states a specific verb ('Select') on a specific resource (the display used by screenshot), making the tool's purpose unambiguous. It naturally distinguishes this from sibling tools like list_displays and screenshot, since it describes a configuration action rather than enumeration or capture.

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 intended usage is implied: use this tool to choose which display screenshots will target. However, the description does not explicitly mention using list_displays to get valid indices, does not state whether the setting persists, and gives no exclusions or alternatives.

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