Динамика курса валюты ЦБ РФ

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

Annotations already declare readOnlyHint=true and openWorldHint=true. The description adds 'без токена' (no token/auth required), which is useful context beyond the annotations, but says nothing about pagination, rate limits, or what happens with invalid currency codes.

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?

Three short sentences, front-loaded with the core promise (daily rates + summary) and the default window. Little waste, though the summary enumeration is slightly list-like.

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?

No output schema exists, so the description carries the return-value burden; it helpfully enumerates the summary fields (min, max, start/end, percent change). Combined with read-only annotations and full schema coverage, this is close to sufficient, though it omits error/edge-case behavior.

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 code/from/to are already fully documented in the schema, including their defaults. The description only restates the default 30-day window and adds no constraints or format details beyond the schema.

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+resource: the CBR currency rate over a period by day plus a summary (min, max, start/end, percent change). It is clear what it does, but it never distinguishes itself from the sibling cbr_rates, so an agent must guess which tool returns history versus the current rate.

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 no when-to-use or when-not-to-use guidance and names no alternative. The default ('последние 30 дней') hints at its purpose but does not help the agent choose between cbr_rate_history, cbr_rates, and cbr_key_rate.

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