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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds the key behavioral fact that the output is aggregated counts rather than bookable slots, plus the operational note that it shares filters with search_slots. It does not mention result limits, cardinality of areas returned, or latency, so it is strong but not exhaustive.

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 before any usage detail, and each sentence carries distinct information (function, contrast with sibling, two use cases, example phrasing). It runs long with multiple illustrative quotations, which adds warmth but also redundancy.

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 burden of describing returns and does so precisely — counts broken out by area, day, time band and price, explicitly not slots. Combined with the usage triggers and shared-filter note, an agent has everything needed to call and interpret it.

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%, with defaults, formats and enum values all documented on the parameters themselves. The description only adds that the filters mirror search_slots, which is useful context but not parameter-level meaning beyond the schema. 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?

The description states a concrete function — returning availability COUNT aggregations by area, day, time band and price — and explicitly contrasts that with search_slots, which returns actual slots. An agent can distinguish it from its sibling without opening either 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?

Two explicit trigger conditions are given (under-specified requests and zero-result searches), plus a reference alternative in search_slots for the case where actual availability is wanted. The concrete example of the clarifying question it enables makes the when/when-not boundary unambiguous.

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