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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds value by naming the margin concept and some output fields (mid_market_amount, amount_after_margin, fees_lost), but it repeats return-value content that a dedicated output schema already carries and says nothing about defaults, rounding, or rate-source expectations.

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 compact sentences, front-loaded with the purpose before the return-value enumeration and the bundle pointer. The '{...}' return preview is slightly noisy given an output schema exists, but nothing is padded.

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?

Parameters are fully documented in schema and return values are covered by the output schema, so the description is minimally sufficient. The missing piece is routing context among dozens of near-identical currency/finance calculators, which an agent would need to pick this tool correctly.

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 including the bank_margin_pct default of 2.5% are already documented in the schema. The description adds no syntax, unit, or constraint detail beyond that baseline.

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 (calculate currency exchange) and adds the distinguishing scope of bank margin and fees lost. However, it never differentiates itself from the many sibling currency tools (calculate_currency_cross_rate, calculate_exchange_margin, calculate_exchange_rate_margin), leaving the agent to infer the boundary.

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 only guidance is a pointer to list_bundles for 'voyage' calculators, which is a directory hint rather than a when-to-use/when-not-to-use rule. No alternative currency tool is named as a fallback or contrast case.

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