Справочник регионов

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

Annotations already declare readOnlyHint and openWorldHint, so the description carries less burden. It adds the ability to filter by name and the example '225 = Россия', but does not disclose other behaviors such as pagination, error handling, or response structure. A score of 3 is appropriate as annotations cover safety and the description adds some context.

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 extremely concise: two short sentences. Every phrase adds value—the directory's purpose, filtering capability, and a notable region code. No wasted words, and the structure is front-loaded with the main purpose.

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?

Given the tool's low complexity (2 optional parameters, no output schema), the description explains the core functionality and filtering. It could be improved by explicitly mentioning that the response is a list of regions with codes and names, but the example '225 = Россия' hints at the return format. Overall, it is fairly complete for a simple lookup tool.

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 parameters are already well-documented. The description mentions filtering by name, which matches the 'search' parameter, but adds no new meaning beyond the schema. Baseline 3 is correct.

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 it is a directory of region codes (GeoRegions) for targeting, with filtering by name. This clearly identifies the tool's purpose as a lookup/reference. The verb 'get' is implicit but the title 'Справочник' (directory) reinforces the read-only nature. It distinguishes from sibling tools which are mostly mutation/campaign management 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?

The description implies usage for targeting with region filters, but does not explicitly state when to use this tool vs alternatives. No exclusions or alternative tool recommendations are given. Given the sibling tools are unrelated, the usage context is adequately implied.

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