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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds genuinely useful context beyond that: the result is a public *signal* only, with no guarantee of bookability and no hold placed — a caveat an agent could otherwise get wrong. It stops short of describing freshness, caching, or timezone handling, so not a 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?

Two short sentences, zero filler, with the scope constraint stated first and the important non-guarantee caveat immediately after. Nothing could be removed without losing meaning.

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 availability check with no output schema, the description should at least characterize what the calendar signal returns or how to interpret it, and should explain the slug. The non-guarantee caveat is a strong addition, but the return semantics remain undefined.

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 carries the full burden for the three required parameters. It mentions check-in and checkout dates but not the date format expectations, the exclusive/inclusive semantics of checkOut, or what the "slug" parameter identifies (it is not mentioned at all). The word "local" is the only added nuance.

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 pairs a specific verb ("Read") with a specific resource ("the public calendar signal for local check-in and checkout dates"), so an agent knows this checks date availability rather than fetching a listing or a price. It does not explicitly name a sibling such as price_hyatus_stay or get_hyatus_stay to sharpen the distinction, which keeps it short of a 5.

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?

Usage is only implied: the tool checks whether given check-in/check-out dates appear free. The caveat that signals "do not guarantee bookability or place a hold" hints that this is a pre-check step rather than a booking step, but there is no explicit when-to-use, when-not-to-use, or named alternative (e.g. pricing or full-detail lookups).

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