Monobank currency rates

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

Annotations already declare readOnlyHint; the description adds useful behavioral facts: authentication is not required, the data is refreshed at most every 5 minutes, and buy/sell/cross have defined meanings. It does not discuss error cases or response format, but these are minor for a public read-only endpoint.

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 sentences, each earning its place: public access, semantics of the returned fields, and filter/refresh behavior. The most important information is front-loaded in the first phrase.

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 read-only public API with one optional parameter and no output schema, the description covers the data semantics, authentication, and refresh behavior. It leaves out possible error conditions when filtering by an unknown code, but that is a minor 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 coverage is 100% for the single optional parameter, so the schema already explains the ISO 4217 alpha code. The description adds 'optionally filter' and examples like USD or EUR, which is helpful but not substantial 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?

The description identifies the resource precisely as 'Public Monobank exchange rates' and explains what buy, sell, and cross mean, making the tool's scope clear. It stops short of a 5 because the text uses a noun phrase rather than an explicit verb like 'returns' or 'gets', although the tool name supplies the action.

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 gives clear usage context: no token is needed, the data is public, refresh happens at most every 5 minutes, and an optional currency filter exists. It does not explicitly compare against alternatives, but the sibling tools are unrelated enough that no exclusion is necessary.

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