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

Annotations already declare readOnlyHint=true, so the description is not required to state that this is a read-only operation. It adds valuable context beyond the annotation: the tool performs spot-rate conversion at request time, has no historical/forward rates, and does not model slippage or fees. It also clarifies that actual swap execution is handled by a different tool, which is useful behavioral disclosure. The only minor omission is whether the rate is live or cached, but this is acceptable given the annotation 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 well-structured with clear 'Use when', 'Limitations', and 'Alternatives' sections. Each sentence serves a distinct purpose, and the most important scoping information (what the tool does) is front-loaded. The text is concise without redundancy, and the alternatives are explicitly named, making it easy for an agent to parse quickly.

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?

Given that the tool has an output schema (as indicated by 'has output schema: true'), the description does not need to explain return values. The description covers the tool's purpose, usage conditions, limitations, and alternatives, which is comprehensive for an agent to call it correctly. Nothing critical is missing for a currency conversion tool.

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% — all three parameters (amount, from_currency, to_currency) have descriptive names and explanations in the schema itself. The tool description does not add any additional parameter-level meaning, such as accepted formats, examples beyond those in the schema, or constraints. Since the schema fully documents the parameters, a baseline score of 3 is appropriate; the description adds no extra semantic value.

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 a specific verb ('Convert an amount') with a specific resource (fiat currencies and crypto assets) and explicitly lists the supported asset classes. It names the two sibling tools it is not (get_token_price, get_dex_quote) and explains the difference, making it unambiguous for an agent to select this tool.

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 includes explicit 'Use when' guidance with concrete examples (converting USD portfolio to EUR, fiat to crypto), and explicitly says for prices only use get_token_price, and for actual swap execution use get_dex_quote. It also clearly states limitations (spot-rate only, no historical/forward rates, no slippage/fee modeling), leaving no ambiguity about when to use this tool versus alternatives.

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