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

Annotations already declare readOnlyHint=true, so the description does not need to restate safety. It adds little beyond 'by ID' and does not mention behavior on missing/invalid IDs or the shape of the returned site. This is acceptable for a simple read but does not exceed the annotation coverage.

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, front-loaded sentence with no filler. It states the resource, verb, and selection mechanism in the most economical form possible for this simple tool.

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 one-parameter read-only tool with readOnlyHint=true, the description is nearly complete for invoking the tool correctly. It could mention what is returned or how missing IDs are handled, but the operation is simple enough that these are minor gaps.

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 input schema already fully documents the only parameter, 'id', as 'Site ID' with 100% schema description coverage. The description merely restates lookup-by-ID and adds no additional format, constraints, or contextual meaning beyond the schema.

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 ('Retrieve'), a clear resource ('a single iubenda site'), and a selection key ('by ID'). This distinguishes it from list_sites and other site-related tools, so an agent can tell exactly what the operation does.

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 that the tool is used when you already have a site ID and want one site, but it does not explicitly state when to use this tool versus alternatives like list_sites when no ID is available. Usage guidance is present only by implication.

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