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

Annotations are absent, so the description carries full responsibility for disclosing behavior. It mentions a cost per call ('$0.02 USDC') and implies it returns search results, but it does not state whether the operation is read-only, what the response structure is, whether pagination is supported (despite a limit parameter), or any authentication or rate-limit requirements. The cost note is a minor positive but insufficient coverage.

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 a single, front-loaded sentence with zero filler. It achieves conciseness, but the brevity sacrifices essential details; still, for the sole criterion of being concise, it is excellent.

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?

The tool is simple (2 params, no output schema), but the description leaves out critical details: return format, result count behavior, and how it differs from ru_page/ru_research/ru_research_deep. An agent cannot fully judge when to invoke it or what to expect from results. The lack of output schema makes a description of the response shape particularly important.

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 0%, and the description does not compensate. It does not explain what 'query' should contain, how results are ordered, or what 'limit' controls (though its default of 5 hints at a cap). The agent must infer semantics from parameter names alone, which is risky for non-obvious behavior like language/locale constraints.

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 ('search') and resource ('web') with a scope qualifier ('Cyrillic'), making the primary purpose clear. It distinguishes from postal and financial siblings but does not explicitly differentiate from similar search/research tools like ru_page, ru_research, or ru_research_deep.

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 offers no guidance on when to use this tool versus alternatives. It does not mention any exclusions, complementary tools, or conditions that would lead an agent to prefer ru_search over ru_page or ru_research. This is a clear gap for a tool with many siblings.

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