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

Annotations already declare readOnlyHint=true, so the safety profile is covered, and the description adds real value by spelling out the returned fields (guest, dates, check-in/out times, channel and its reference id, price, prepayment/deposit status, guest-app URL) plus the underlying API endpoint. It stops short of noting behavior on missing/invalid ids, which keeps it from a 5.

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 the verb/resource first and the return-field inventory folded into the same sentence; no filler. The field list is long but it is load-bearing given there is no output schema.

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?

With no output schema, the description carries the return-value burden and does so effectively by enumerating the fields returned. What an agent needs to call it correctly is present; only edge-case behavior (not found, auth scope) is unaddressed.

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% for the single reservation_id parameter, so the schema already documents it — baseline 3 applies. The description only reinforces "by id" and embeds {reservationId} in the endpoint path, adding no format or constraint detail 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?

States a specific verb and resource ("Fetch one reservation by id") and enumerates the payload the agent receives, which cleanly distinguishes it from the sibling smoobu_list_reservations. An agent can tell what this does without opening the schema.

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 implied by "by id" — the agent infers it needs a reservation_id, likely obtained from smoobu_list_reservations — but no alternative is named and no when-to-use/when-not guidance is given. It is minimum viable routing, not explicit.

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