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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description usefully adds behavior beyond that: the output shape (one full-day tour, or a morning/afternoon pair, with from-prices and links), that multi-day tours are listed separately, and the important limitation that availability, seats, and group totals are unverified.

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 sentences, front-loaded with the core action and only lightly redundant on the days default that the schema already specifies. The output-shape sentence earns its place by telling the agent what a response looks like.

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 3-parameter read tool with a full output schema and rich annotations, the description supplies the essential caveat about unverified availability plus the structure of the returned plan. An agent has enough to call it correctly; only explicit sibling routing 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 67% and the description largely restates what is already there (destination, days 1-7 with default 3). It does add marginal value by widening the interests example from the schema's 'food and history' to 'food, history, or boat trips'. Baseline 3 is 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?

A specific verb (suggest/plan) applied to a specific resource (a day-by-day plan of bookable TripWays tours) with a stated scope (a destination). It clearly distinguishes itself from siblings like search_tours and compare_tours, which return raw listings rather than an assembled itinerary.

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?

The closing caveat that 'dates, seats, and group totals are not checked' implies this is not the tool for firm availability, which nudges toward check_availability/get_price_quote, but no sibling is named and no explicit when-to-use/when-not statement is given. Usage is only implied.

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