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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds the underlying endpoint (GET /v1/admin/availability/{catalogItemId}/period) and reinforces the pre-order timing, but never says what a 'check' returns — a boolean, a set of bookable slots, or per-location detail — which is the key unknown for an agent, especially with no output schema.

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 plus the endpoint reference, front-loaded with the purpose and the timing caveat, with no filler. Every clause carries information an agent does not already get from the schema or annotations.

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?

For a read-only predicate tool this is close, and the pre-order guidance plus the endpoint are useful. Missing is any indication of the result shape or how partial availability is expressed, which matters because there is no output schema to fall back on.

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 all four parameters are documented in the schema itself; the description only echoes the ISO 8601 UTC format and the single-item constraint. It adds no semantics for location_ids, such as whether omitting it checks all locations.

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?

Uses a specific verb and resource ('check whether one catalog item can be booked for a date-time window') and scopes it to a single item, which distinguishes it from the list_* siblings that return collections. The parenthetical '(before you create an order)' pins the intent further.

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?

The phrase 'before you create an order' gives a clear workflow trigger for calling this tool. It does not name an alternative or state exclusions, but no sibling tool offers comparable availability checking, so there is little to route away from.

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