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

The readOnlyHint already signals a safe read, and the description goes beyond annotations by describing the return payload in detail (time, state, notes, client, each service with staff and price in cents, cancellation details, tags) — effectively compensating for the absent output schema. It stops short of covering not-found/error behavior, so it is not fully complete.

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?

Front-loaded with the verb and resource, then a compact em-dash list of return fields; no wasted sentences. The trailing 'GraphQL: appointment.' is mildly cryptic jargon, which keeps it just short of a 5.

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 single-parameter read tool with no output schema, the description supplies the return shape and the annotations cover read-only safety, leaving little an agent needs to know to call it. The only real gap is error/not-found behavior.

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?

With one parameter at 100% schema description coverage, the schema already documents the appointment_id format (urn:blvd:Appointment:<uuid>). The description's 'by id' adds no syntax or format detail beyond that, so the baseline 3 applies.

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 appointment) and explicitly scopes it to a single record by id, which distinguishes it cleanly from the sibling boulevard_list_appointments. It even enumerates the returned facets, so an agent knows exactly what this call is for.

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 'by id' phrasing implies the tool is for when you already have an appointment id, but it never states when to choose this over boulevard_list_appointments or what to do if the id is unknown. Usage is inferable rather than stated, so this sits at the minimum-viable level.

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