Даты продажи ЖД

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

Annotations already cover read-only, idempotent, non-destructive, open-world behavior. The description adds useful behavioral details beyond annotations: it is a cheap/lightweight call, and an invalid station-code pair produces an empty response. This edge-case disclosure is valuable.

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 two short sentences, front-loads the core purpose, and then adds a key edge-case detail. Every sentence earns its place and there is no redundant wording.

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 tool with an output schema and annotations covering safety, the description provides enough to call it correctly: the purpose, the station-code requirement, and the observed empty response for invalid codes. The only notable omission is contextual info about origin/destination code sources, but this is not a critical blocker given the simple design.

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?

The schema has 0% description coverage, so the description must compensate. It does clarify that origin and destination refer to a pair of station codes and that input coordinates point to a direction. However, it does not explain that the limit parameter controls the number of returned dates or any format expectations, leaving a meaningful gap.

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 what the tool does: it provides the dates for which train ticket sales are open for a given direction. The title confirms the resource (ЖД dates). It is clear enough to distinguish from siblings like train_search or train_seats, though it does not explicitly name any sibling.

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 not only implies its main use — checking open sale dates for a route — but also explicitly offers a secondary use: a cheap way to validate a pair of station codes, since an invalid pair yields an empty response. It does not directly compare itself with alternatives, but the guidance is actionable.

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