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

Annotations already declare readOnly/idempotent/non-destructive, so the description's job is to add beyond that, and it does: 'returns up to 12 rows' discloses truncation against a catalog of 20 tours, and it clarifies hotel pickup inclusion and the price-unit semantics. Minor gap: it does not explain how to retrieve the remaining rows beyond the 12 cap.

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?

Content is front-loaded with the catalog summary before the pricing caveat and filter details, and it is reasonably compact. It drifts slightly into return-field semantics (fromPriceUsd, priceUnit) that read more like output documentation than tool selection guidance.

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 returns, and it does cover the price fields, party-size semantics, row cap, and pickup inclusion. It is nearly complete, leaving only the behavior above the 12-row cap unexplained.

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 100%, so the two parameters (area, query) are already fully documented with examples, making 3 the baseline. The description confirms they are optional filters but adds no syntax or matching behavior beyond the schema. Note the price-field explanation in the description refers to response fields, not parameters.

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?

The description names a specific verb (list) and resource (the 20 private tours and day packages) with concrete scope (Jamaica, named attractions). It also implicitly contrasts with get_tour by noting that the list is the catalog overview while get_tour computes an exact total. An agent can distinguish it from siblings like get_tour and start_tour_booking without opening a 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?

It routes clearly: use get_tour with guests for the exact total, implying this tool is for browsing/comparison rather than pricing a specific booking. It states the optional filters and the returned row cap. It stops short of an explicit 'when not to use' beyond the get_tour pointer, so it is strong but not exhaustive.

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