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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds genuine behavioral context beyond that: the 48-hour turnaround constraint and the fact that a negative result yields suggested_open_windows. It doesn't clarify pagination or what 'open' precisely means, 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 front-loaded sentences with no filler; the core check comes first and the fallback behavior second. The closing imperative is slightly operational rather than descriptive, but it earns its place by preventing a mishandled response.

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 partially compensates by describing the suggested_open_windows return on failure. It leaves open what an 'open' result looks like and omits follow-up paths like request_hold, but is otherwise sufficient for a read-only availability check.

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 100%, so start/end/nights/requester are all documented in the schema itself. The description adds no parameter meaning (e.g., no relationship between nights and end, no note on the nested requester object), so baseline 3 applies.

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?

States a specific verb and resource ('Check whether specific dates are open') and scopes it with the 48-hour turnaround rule. An agent can distinguish this from siblings like find_open_windows or request_hold 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 clear context for the failure path ('If not open, returns suggested_open_windows nearby — always offer those to the guest'), which is actionable usage guidance. It stops short of explicitly contrasting when to call this versus find_open_windows or request_hold, so no explicit alternative routing or exclusions.

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