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

Annotations already declare readOnlyHint=true, so 'Read-only. GET /free-slots' adds nothing. What does add value is the disclosure that results are returned per practitioner as start/end in UTC and that the window is capped at 7 days. It still doesn't say whether non-working hours, existing appointments, or service duration are factored in — the key behavioral question for a slot finder.

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?

Three compact sentences, front-loaded with the resource and scope, then the return shape, then transport. The only waste is 'Read-only. GET /free-slots,' which duplicates the readOnlyHint annotation.

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 briefly (per-practitioner start/end in UTC). Combined with the 7-day window limit and required service/location/practitioner scoping, an agent has enough to invoke it correctly, though the slot-generation semantics remain unstated.

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 coverage is 100%, so every parameter is already documented in the schema, which sets the baseline at 3. The description reinforces the from/to pairing and the 7-day ceiling but adds no meaning for 'interval' or the 20-practitioner cap beyond what the schema states.

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?

The description states a specific resource ('Bookable free slots') and its scoping inputs (practitioners, location, one service, from/to window), which is far more than a restatement of the name. It doesn't explicitly name how it differs from close siblings like splose_get_practitioner_availability or splose_list_busy_times, so it falls short of a 5.

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 only implied: 'Bookable free slots ... for one patient service' suggests the booking flow, and the 7-day window cap is a real constraint on use. But there is no explicit when-to-use/when-not guidance and no routing against the availability and busy-times siblings, which an agent would plausibly confuse this with.

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