Справочники

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

Annotations already cover read-only and idempotent behavior, and the description adds a useful behavioral caveat: GeoRegions can be very large, steering agents away from unnecessary large payloads. This goes beyond the annotations without contradicting them.

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 sentences, front-loaded with the core purpose, followed by concrete examples and a single actionable caveat. There is no filler or repetition of schema content.

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 one-parameter read-only operation with a fully documented enum and clear sibling differentiation, the description covers everything an agent needs to select and invoke the tool correctly. No output schema is present, but this is acceptable for a well-known dictionaries endpoint.

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 already documents the names parameter fully with an enum and a description, so the description does not need to restate parameter details. It adds a relevant example list, but that is already reflected in the schema, so baseline 3 is appropriate.

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 verb ('Возвращает справочники') and resource ('справочники Яндекс Директа'), then lists concrete examples such as currencies, time zones, constants, and ad categories. It also distinguishes itself from get_regions, so an agent can tell them apart immediately.

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 explicitly identifies the alternative get_regions for the case where the agent needs to search regions, warning that GeoRegions can be very large. This gives clear when-to-use and when-not-to-use guidance for the main edge case.

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