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

Annotations already establish readOnly, idempotent, non-destructive, closed-world behavior. The description adds genuinely new context beyond them: that this server never performs bookings, that the patient completes booking via bookingUrl, and that each result carries a FHIR Slot resource. No auth or rate-limit detail, but the operational boundary is clear.

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?

Two sentences, no filler. The scoping constraint comes first and the non-booking handoff behavior second, so the most decision-relevant fact is front-loaded.

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 at a useful level: it names the FHIR Slot resource and the bookingUrl field per slot. It stops short of describing result ordering, empty-result behavior, or pagination, which leaves a small gap for a discovery tool.

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 days/from_date/clinic_slug/service_variant_id are fully documented in the schema itself. The description only restates the 14-day cap and the single-clinic/single-variant scoping, adding little syntax or format meaning beyond the schema. Baseline 3 is appropriate.

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 with tight scope: free slots for exactly one bookable service variant at one clinic, capped at 14 days. An agent can distinguish it from get_next_available_date (a single date) by the plural 'slots' and the FHIR Slot payload, though no sibling is named explicitly.

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 rather than stated: 'this server never books' and the bookingUrl handoff tell the agent this is a discovery-only step, not a booking step. However, no alternative tool (get_next_available_date, list_clinic_services) is named with a condition that would route the agent to it.

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