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

Annotations already cover safety (readOnly, idempotent, non-destructive, closed-world), but the description adds meaningfully more: the daily doctor limit exemption, the enrolment-status vocabulary (yes/restricted/no/does not apply/unknown), which fee table is returned, and the operational advice that enrolment/fees change often and the person should phone to confirm. That is real behavioral context beyond the structured fields.

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 core purpose and triggering situations, and every part is generally useful given there is no output schema. However the long run-on 'Each practice: ...' enumeration is dense and could be more scannable.

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 full return-value burden and does so thoroughly (enrolment status, enrolment note, fee table, contact fields, hours, languages, doctor_ids, last-updated date). It also supplies the domain model (enrolment lowers cost, GP referral is the usual path to public specialists) needed to interpret results correctly.

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 the schema already documents all 8 parameters including both enums. The description largely restates schema content (kind subtypes, enrolment meaning, age->fee row) rather than adding new parameter interpretation, 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?

Specific verb+resource (find/list New Zealand general practices, or urgent care clinics, near a place, from Healthpoint), plus the scope is narrowed against siblings by noting 'Practices are not doctors, so this does not count toward the daily doctor limit' and pointing to get_doctor for doctor_ids. An agent can distinguish this from search_doctors/get_doctor without opening any 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?

Names concrete triggering situations: 'when the person needs a GP, wants to enrol with a practice, or needs urgent but not emergency care.' It also routes to get_doctor (doctor_ids) and clarifies the doctor-vs-practice boundary. There is no explicit 'when not to use' other than that boundary, so it stops just short of a 5.

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