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

Annotations already declare readOnlyHint/idempotent/non-destructive, so the safety profile is covered; the description instead discloses the shape of what comes back (reserve_days, book_by dates, fallbacks, provider alternatives). It does not discuss freshness of fares or rate limits, which would matter for an openWorldHint tool, keeping it short of a 5.

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 ordering rule, then alternatives semantics, then the sibling hand-off — a sensible priority order with no filler. The middle sentence is long and packs several return-shape details into one run-on clause, which slightly hurts scanability.

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 explaining the return structure and does so (ordered steps, reserve_days, book_by, fallbacks, provider alternatives). What remains unstated — how tier/lang alter output, or how flights appear when origin is omitted — is covered adequately by the schema descriptions.

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 (city, persona, friday, origin, tier, travellers, lang) is already documented with format and defaults. The description mentions none of them by name, adding nothing beyond what the schema supplies; 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?

States a concrete resource (booking links and checklist for a weekend) plus its organizing principle (ordered by scarcity / lead time). It explicitly names the sibling it is not ('For a plan an agent can execute ... use booking_manifest instead'), so an agent can separate the two 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?

Gives imperative usage rules ('Book in list order') and the alternatives condition ('compare them and book one, not both'), and routes the agent to booking_manifest when it needs an executable plan. When-to-use, how-to-use and when-to-use-something-else are all present.

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