List displays

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds context beyond annotations by detailing the returned data (index, resolution, position) and its intended use. The 'Read-only' remark is redundant with annotations but not contradictory.

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 sentence, front-loads the core action and result, and immediately states the use cases. Every clause adds value without redundancy or fluff.

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 stateless, parameterless read-only tool, the description is nearly complete. It states what is returned and why. A minor gap is not explicitly noting the zero-based nature of display indices or the exact output format, but these are inferable from the list of nouns and the reference to screenshot(display: N).

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 zero parameters and the schema coverage is 100% (empty schema fully describes the input). With no parameters to document, the baseline of 4 applies; the description correctly focuses on output and purpose rather than parameter details.

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 uses a specific verb ('List') and resource ('attached display'), and specifies what is returned: index, resolution, and position. It also explicitly ties the tool's purpose to downstream use with screenshot(display: N) and multi-monitor coordinate interpretation, making it clearly distinguishable from all sibling tools.

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 gives explicit usage context: this is the tool to call before taking screenshots on a specific display or when working with screen coordinates on multi-monitor setups. It effectively tells an agent when to select this tool among the many siblings.

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