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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so safety and world scope are covered. The description adds genuine behavioral context beyond that: results render as their own section BELOW unit results and enrich the selection, and each package carries included extras and a direct booking link. It stops short of mentioning auth needs, rate limits, or result cardinality, hence a 4 rather than 5.

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?

The critical ordering constraint is front-loaded and capitalized, which is the right structure. However, the same ordering rule is restated three times ('AFTER the units', 'never call it first', 'never instead of the unit search'), which is somewhat redundant, and the theme list is repeated between the routing sentence and the resource sentence.

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 9-parameter, no-required, no-output-schema tool, the description supplies the essential missing context: the ordering relationship to search_stays, the thematic trigger conditions, and what a returned package contains. Since there is no output schema, it could say slightly more about the shape/volume of results, but nothing critical for correct invocation 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 89%, so the schema already documents the parameters well (including the 'always pass along' guidance on adults, children, pets, check_in/out). The description reinforces the theme concept by listing romance/wellness/dog/culinary, which maps to the theme enum, but adds no format or filtering detail beyond the schema. 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?

The description states a specific verb and resource — 'List themed holiday packages (promotional bundles) across properties' — and enumerates the themes (dog, romance, wellness, culinary) plus what each contains. It explicitly distinguishes itself from the sibling search_stays ('never instead of the unit search'), so an agent can separate it from siblings 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?

Gives an explicit when ('when the brief carries a package theme... or the guest asks for deals'), an ordering rule ('call this AFTER search_stays in the same turn'), and hard exclusions ('never call it first, never instead of the unit search'). It also supplies trigger examples ('romantic getaway package', 'dog holiday with meals included'), leaving nothing to inference.

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