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

readOnlyHint=true already declares the safety profile, yet the description goes further and discloses the returned surface — time, state, notes, client, services with staff and price (in cents), cancellation details, tags. The 'price (in cents)' unit and the field inventory are genuine additions that compensate for the absent output schema. It does not cover not-found/error behavior, which keeps it short of 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?

One front-loaded sentence covering operation, identifier and return shape, with no filler. The trailing 'GraphQL: appointment.' is terse and slightly cryptic but still earns its place as a backend-type mapping.

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 read-only, single-parameter lookup with no output schema, the description supplies the return-field inventory that the structured fields omit. Nothing essential to calling it correctly is missing, though error/not-found handling 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% and the single appointment_id is already documented with a urn:blvd:Appointment:<uuid> example. The description adds only 'by id', so the schema does the heavy lifting and 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 contrasts implicitly with the list siblings via 'one ... by id'. It also enumerates exactly what each record contains, so an agent knows both the operation and its payload.

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?

'Fetch one appointment by id' implies the keyed-lookup use case, but it never names an alternative sibling (e.g. boulevard_list_appointments for browsing/filtering) or states when not to use it. Usage is inferable but not spelled out.

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