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

Annotations already declare readOnly/idempotent/destructive=false, so the safety profile is covered; the description still adds real value by disclosing Nookal's 60-day hard limit, that it books nothing, and the exact shape of each returned slot (date, 24h clinic-local start time, provider id, location id). It omits rate limits or pagination behavior for a potentially large multi-day result set.

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 dense paragraph that front-loads the main action and scope, with the 60-day constraint and read-only note placed early. Every sentence carries information, though the trailing GraphQL endpoint reference is nice-to-have rather than essential.

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 usefully enumerates the returned slot fields, and it covers the date-range constraint and optional filters. It leaves pagination/result-size behavior unaddressed for a query that can span 60 days, which is the only notable gap.

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 every parameter is already documented in the schema. The description names locations, practitioners and service but adds no syntax or format meaning beyond that, and never mentions slot_duration at all. 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 and resource ('Get the free appointment slots per date between two dates') plus scope (max 60 days), clearly distinguishing it from nookal_list_appointments which returns booked appointments. An agent can tell immediately that this is a free-slot search.

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?

It gives useful context (60-day cap, optional location/practitioner/service filters, points to list_services for service_id) but never states when to choose this over a sibling like nookal_list_appointments, nor any exclusions or prerequisites.

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