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

With no annotations provided, the description carries the full burden of disclosing behavior. It adds useful context about caching (hourly) and the cost ('Free'), which helps an AI agent set expectations. It doesn't mention output format or error behavior, but for a simple read-only tool this is adequate.

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, information-dense sentence with no filler. It front-loads the core purpose and includes essential behavioral details without unnecessary length.

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 tool with one optional parameter and no output schema, the description covers the key aspects: what it returns (rates per unit), freshness (cached hourly), and cost (free). It could be more explicit about what happens when 'codes' is omitted, but overall it is complete enough for basic selection and invocation.

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?

The schema has zero description coverage for the 'codes' parameter, but the description hints that codes are currency codes (USD/EUR/etc), adding meaning beyond the raw schema. It doesn't explicitly explain the parameter's usage or default behavior, but the implication is clear.

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 clearly states the tool provides live KZT exchange rates per unit of other currencies (USD/EUR/etc), making the resource and action unambiguous. It distinguishes itself from the sibling fx_rates by focusing specifically on KZT.

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 tool's purpose strongly implies use for KZT rate lookups, but there is no explicit guidance on when to use this vs. fx_rates or other alternatives. 'Cached hourly' hints at freshness limitations but not usage context.

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