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

Annotations already declare read-only, idempotent, non-destructive, and closed-world behavior. The description adds useful operational context beyond annotations: the 90-day range limit and the default behavior that 'days without a row use the plan's base price.' It does not cover auth or rate limits, but it meaningfully extends the behavioral picture.

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 three tightly written sentences. It is front-loaded with the usage trigger, follows with the return behavior and fallback semantics, and closes with the exclusion. Every sentence earns its place.

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?

An output schema exists, so return formatting need not be explained. Annotations cover the safety profile, and the description supplies the usage trigger, scope, fallback behavior, and explicit exclusion. Nothing an agent needs in order to call this correctly 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 100%, so the schema already documents all four parameters with patterns and descriptions. The description reinforces that the tool operates on one rate plan and specific nights, but adds no syntax or format detail beyond the schema. Baseline 3 is appropriate when the schema carries the parameter burden.

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 names a specific verb and resource: it 'Returns the stored per-day price and restrictions of one rate plan over up to 90 days.' It also distinguishes the tool from siblings by specifying that it is 'Not for whether rooms are free,' which contrasts with the availability-focused tools.

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?

It gives an explicit when-to-use trigger ('when someone asks what a rate costs on specific nights, or about minimum stays, stop-sell or closed-to-arrival dates') and an explicit when-not ('Not for whether rooms are free'). The exclusion effectively routes the agent away from availability tools, even though the alternative tool is not named by exact name.

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