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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safe, closed-world read profile is covered. The description adds that each facet carries a count of sailings, which is behavioral-ish context, but gives no detail on response shape or size. Adequate given the low annotation burden but not rich.

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?

Two short sentences, zero filler, front-loaded with the returned facet list. Every clause carries 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 and no parameters, the description must carry the return-value burden, and it enumerates the facet categories and the count field clearly. It could say a bit more about how tier or months-on-sale are structured, but it is sufficient for an agent to call the tool 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?

The tool takes zero parameters, so the baseline is 4. The description rightly spends its words on what can be filtered rather than on inputs, and there is no parameter semantics gap to fill.

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 the specific resources returned (regions, cruise lines with tier, ports, months on sale) and their sailing counts, which is concrete and distinguishable from search_cruises. It lacks an explicit verb like 'list' or 'returns', leaving the action implied, but the resource set is unambiguous.

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 the values the search filters accept' implies the tool should be consulted before invoking search_cruises, which is useful context. However, it never explicitly says when to call it versus siblings, nor does it name an alternative or state prerequisites.

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