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

Annotations already declare readOnlyHint=true, openWorldHint=false and destructiveHint=false, so the safety profile is covered. Beyond that, the description adds real behavioral context: results include both owned and shared sites, and the your_role field indicates which is which — information an agent could not infer from the annotations.

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?

A single short sentence with the essential scope front-loaded and no filler. Nothing could be removed without losing 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?

An output schema exists, so return-value details need not be explained, and with no input parameters the description only has to convey scope — which it does. The only shortfall is the absence of any routing advice among the many sibling list_* tools, which is minor for such a simple operation.

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, so there is no parameter meaning for the description to add; the baseline for a no-param tool applies. The parenthetical about your_role describes response content rather than input, which is a minor bonus rather than a gap.

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 specific verb and resource ("List sites") and adds meaningful scope: both owned sites and sites shared with the caller. That distinguishes it from a hypothetical owned-only lister, though it does not explicitly name or rule out any sibling tool.

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?

Usage is only implied — the tool takes no parameters and the description never states when to reach for it versus other listing tools. For a zero-argument list operation this is largely self-evident, but there is no explicit when/when-not guidance or prerequisite context.

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