Пересчёт суммы по курсу ЦБ

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety bar is lower; the description still adds value by stating 'без токена' (no token needed), which is auth context not present in annotations, plus that the rate is the official CBR rate and the date defaults to today. It does not describe pagination or return format, but for a read-only tool that is minor.

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 tight sentences, front-loaded with the conversion verb and scope, then the mechanism, then use cases, then the read-only/auth note. No wasted words.

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 conversion tool with fully documented parameters and readOnly/openWorld annotations, the description covers purpose, mechanism, and auth adequately. It omits what the response contains (converted amount, rate applied), but with no output schema this is a modest gap.

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 all four parameters (amount, from, to, date) are already documented in the schema; the description adds the mechanism ('via ruble') and the official-rate-on-date semantics but no syntax or format detail beyond the schema. Baseline 3 applies when the schema carries the load.

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?

States a specific verb (пересчитывает/converts) plus resource (amount between ruble and any CBR currency, or cross-currency via ruble) at the official rate on a date. It implicitly separates itself from rate-listing siblings like cbr_rates and cbr_rate_history by being a conversion tool, but never names an alternative explicitly.

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?

Provides use-case examples (invoice, report) that imply when it fits, and clarifies the conversion paths (RUB↔currency or currency↔currency via RUB). However, it gives no when-not guidance and does not route the agent away from siblings such as cbr_rates or cbr_rate_history, so usage is only implied.

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