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

Annotations only declare readOnlyHint and openWorldHint; the description adds meaningful behavior beyond them — results are filtered to actual availability, totals include fees and taxes, ordering is cheapest first, and each result carries links and offer_ids. It does not mention latency, empty-result behavior, or whether availability is live, leaving some behavioral gaps.

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 sentence that front-loads the action and scope, then the return characteristics, then the usage trigger. No filler clauses or restatement of the title.

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 10-parameter search tool with no output schema and thin annotations, the description supplies what the structured fields do not: result ordering, what the totals include, and the offer_id handoff to get_quote. Nothing essential to correct invocation is missing.

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, including defaults, ranges, and the all-in USD semantics of max_total. The description adds only the framing that totals are all-in, which the schema already states for max_total — baseline 3.

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 ("Searches vacation rentals") plus the scoping constraint (available for given dates in a place) and the return shape (all-in totals, cheapest first). An agent can distinguish this from get_quote and book without opening the 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?

"Use when the traveler doesn't have a specific listing yet" gives a clear selection condition, and the mention of offer_ids for get_quote implicitly routes the alternative case. It stops short of explicitly naming the when-not case ("if they already have a listing, use get_quote"), so it is strong but not exhaustive.

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