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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds non-obvious payload context: the response includes contact details, notes, and every booking the guest has made, which signals a potentially large aggregated result beyond the single guest entity.

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?

One tight sentence with the action front-loaded, followed by the backing endpoint. No filler content.

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 simple single-parameter read with no output schema, the description compensates by enumerating the returned fields. It omits error behavior (e.g. invalid id) and auth requirements, but nothing essential to invoking it correctly is missing.

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 description coverage is 100%, so baseline is 3, but the description adds meaning the schema does not: it explains that guest_id is 'the guestId on a reservation', telling the agent where to source the identifier. This clarifies a genuinely ambiguous id.

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?

States a specific verb (Fetch) and resource (one guest) and scopes it to a single record, which cleanly distinguishes it from the sibling smoobu_list_guests. It also names the returned content, so an agent knows exactly what this retrieves versus a list call.

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 'one guest by id' phrasing implies the usage condition (single-record lookup vs listing), but there is no explicit when-to-use/when-not guidance or a named alternative such as smoobu_list_guests. Usage is inferable but not stated.

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