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

Annotations already declare readOnlyHint=true, openWorldHint=true, and destructiveHint=false, so the safety profile is covered. The description adds one genuinely non-obvious behavioral trait: unavailable or unknown calendar signals are retained rather than filtered out. It says nothing about what the comparison returns, ordering, partial failures on bad slugs, or latency.

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?

A single dense sentence that front-loads the comparison scope before the retention caveat, with no filler. It could be slightly more structured (e.g., separating scope from return behavior), but nothing is wasted.

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 five parameters at 0% schema description coverage and no output schema, the description carries a heavy burden and only partly meets it: scope and retention are covered, but return shape and two parameters' semantics are not. An agent could call it, but would not know what the comparison output looks like.

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 0%, so the description must compensate; it clarifies that slugs are compared as a set against shared dates and guests, which is meaningful semantics beyond the bare array schema. However bedrooms, date format expectations, and behavior when checkIn/checkOut are omitted are left entirely undocumented.

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?

Names a specific verb (Compare) and resource (public Hyatus listings), with explicit scope of one to twelve listings and shared stay dates. It is clearly a multi-listing comparison rather than a single-listing fetch, though it does not name which sibling to use for single-listing or search needs.

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 phrase 'for the same stay dates and guest needs' implies the intended scenario: evaluating several candidate listings side by side. There is no explicit when-not guidance or named alternative for single-listing lookups, pricing-only checks, or availability checks, so routing must be inferred from sibling names.

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