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

Annotations cover the safety profile (readOnly, openWorld, idempotent, non-destructive), yet the description still adds substantial behavioral detail the annotations cannot: results are ranked from Vienna/the departure city, weather carries a credit and is sourced from MET Norway/OpenWeather when dates are near and otherwise Copernicus typical values (labelled), prices are explicitly marked 'estimate, not a quote', and the reply ends with a see_more payload. It also imposes an output obligation ('Always show the TripHook links... with the weather credit') and states no personal data is involved.

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?

Dense but front-loaded: the usage trigger leads, parameter guidance follows, then the result contract and the output obligation. It is on the long side and repeats a few schema facts, but nearly every clause carries new information.

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 fully carries the burden: it enumerates each result field (city, country, why it matched, weather plus credit, estimated price, TripHook link), describes the trailing see_more object, and specifies the presentation obligation. An agent has everything needed to call and report correctly.

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 in the schema, which sets the baseline at 3. The description restates the optional set, the limit cap of 20, and the 'give dates or month' rule, adding convenience but no meaning beyond the structured fields.

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+resource (destination search) and pins the exact scope: the same signed-out TripHook Discover search ranked from Vienna or a given departure city. The quoted trigger phrase "where should I go" and the budget/temperature/mood/date framing make it trivially distinguishable from siblings like list_cities and search_public_hooks.

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 a clear activation context (any 'where should I go' question with budget, temperature, mood, dates or month) and an implicit boundary via 'signed-out'. It does not name a competing sibling tool or state when NOT to use it, so it falls short of an explicit when/when-not/alternative statement.

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