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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), and the description adds value on top: it discloses what is computed (fees and daily costs included), that it returns an optional deep link for further editing, and that no external prices are fetched. Missing only pagination/return-shape detail, which is minor here.

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?

Three dense sentences with zero filler: purpose/scope first, then the return value, then the negative boundary. Everything is front-loaded and each sentence earns its place.

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 two-parameter comparison tool with no output schema, the description covers purpose, scope, what is computed, the optional return link, and the no-external-data constraint. It is nearly complete; only the travelers parameter's role is left entirely to the schema.

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 50%, so the schema carries part of the load. The description conveys that offers include fees and per-person daily costs, aligning with bookingCost/dailyCost fields, but says nothing about the travelers parameter or the defaults documented in the schema (nights, baggageCosts, transferCosts). Adequate but does not compensate for the coverage gap.

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 (compares travel offers) with an explicit scope (two to five fully user-entered offers) and enumerates what is included (fees, daily costs). It also carves out what it is not (no external prices fetched), which separates it from siblings like create_trip_plan and last_minute_checklist.

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?

Implies the usage context well: it operates on 2-5 user-entered offers and explicitly does not retrieve external prices, which is a useful boundary condition. However, it never names an alternative tool or states when to prefer it over create_trip_plan or last_minute_checklist, so routing guidance is only implied.

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