get_availability

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

Annotations already declare readOnlyHint=true and openWorldHint=true, and the description is consistent with a pure read. It adds interpretation context (a missing library means no ownership of that edition; waits are estimates), but says nothing about batching limits, rate limits, or how live the 'current' data is.

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 tight sentences with the main capability front-loaded and the caveat second. Slightly clipped phrasing ('A library missing from a title's list') costs a little clarity but there is no filler.

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 an output schema present and annotations covering the safety profile, the description only needs to add result-interpretation and routing, which it does. The remaining gap is operational detail (batch size of 50 title_ids, data freshness) rather than anything essential for correct invocation.

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 both parameters are already documented, including that title_ids are edition-specific OverDrive ids and that libraries overrides defaults. The description reinforces the edition/library scoping but adds no new syntax or formatting detail, making baseline 3 appropriate.

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 names the concrete payload (current copies, holds, estimated wait) scoped to 'specific editions at each library', which is far more specific than the tool name alone. It implicitly separates this lookup from mutation siblings like place_hold or borrow, though it never says outright that it only reads data.

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 explicitly routes the agent: if a library is absent from a title's list, that library doesn't own the edition, and search_titles is the way to find other editions. That is a real when/when-not rule with a named alternative, though no guidance is given about follow-up actions (e.g. place_hold) once availability is known.

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