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

Annotations already establish read-only, idempotent, non-destructive, closed-world behavior. The description adds useful context beyond annotations: the data is a snapshot refreshed hourly and capped at 120 days, so the agent knows results may be stale and must be confirmed elsewhere.

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 description is only two sentences and front-loads the core behavior, scope, and freshness limitation. Every sentence adds value, especially the alternative-tool routing.

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 simple read-only availability query with full schema coverage and annotations, the description is largely complete. It does not describe the return shape, but with no output schema and a straightforward calendar concept, that gap is minor.

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 the input schema already documents apartment, from, and days semantics, including defaults and the 120-day maximum. The description reinforces the night-by-night and one-apartment scope but adds little parameter-level detail beyond the schema.

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 resource and scope: night-by-night availability for one apartment over up to 120 days. It also distinguishes the tool from live search and quote tools by naming search_availability and get_quote explicitly.

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 description clearly routes live availability and price confirmation to search_availability or get_quote, implying this tool is for snapshot calendar browsing. It does not spell out every when-to-use condition, but the key alternative is explicit.

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