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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds real value beyond that: the result structure (from-prices, links, multi-day tours listed apart) and the important caveat that availability, seats, and group totals are unverified. It does not discuss result size, empty-result behavior, or rate limits.

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?

Four sentences, front-loaded with purpose, then parameters, then output shape, then the caveat — each carrying distinct information with no restatement or filler.

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 three-parameter read-only suggestion tool with an output schema, nothing essential is missing: inputs, result structure, and the key limitation (no live availability) are all stated. The remaining gaps, such as empty-destination handling, are minor.

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 coverage is 67%; the description reinforces the days bounds (1 to 7, default 3) and broadens the interests examples to 'food, history, or boat trips' beyond the schema's single example. It explains what interests actually do (shape the suggested plan), which the schema does not.

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 — 'Suggest a day-by-day plan of bookable TripWays tours for a destination' — and the structured shape of the result (full-day tour or morning/afternoon pair, multi-day listed apart). This is clearly distinct from siblings like search_tours or compare_tours, which return flat lists or comparisons rather than a plan.

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?

'These are suggestions only: dates, seats, and group totals are not checked' establishes the planning context and implicitly routes verification to check_availability/get_price_quote. It never names an alternative tool explicitly, so the agent must infer the handoff rather than being told it.

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