currency_convert按最新或指定日期汇率换算两种货币金额，货币用 ISO 三字母代码。Example: {"amount":100,"from":"USD","to":"CNY"}
| Name | Required | Description | Default |
|---|---|---|---|
| to | Yes | 目标货币代码，如 CNY、EUR、HKD | |
| date | No | 历史日期 YYYY-MM-DD，留空取最新 | |
| from | Yes | 源货币代码，如 USD、CNY、JPY | |
| amount | No | 金额，默认 1 |
Changes observed during successful MCP inspections.
Input schema / examplesAdded value: +[
+ {
+ "amount": 100,
+ "from": "USD",
+ "to": "CNY"
+ }
+]Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered and the description only adds that rates are 'latest or for a given date'. It does not disclose the rate source, rounding or precision behaviour, or whether historic lookups can fail for unsupported dates/currencies.
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 definition is one compact sentence plus an example, with the core operation front-loaded. The inline example duplicates the schema's examples array, which is mild waste but does help an agent read the call shape 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?
For a four-parameter read-only conversion tool the description covers the operation and its date option, but with no output schema it never says what comes back (rate only, converted amount, both, precision). That return-value gap is the main thing an agent must guess before relying on the result.
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 are already documented in the schema, and the baseline of 3 applies. The description reinforces the ISO three-letter code convention for the currencies and repeats the schema's own example object, adding little new meaning.
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 states a specific verb and resource: convert an amount between two currencies using the latest or a specified-date rate, with ISO three-letter codes. This is clear enough to act on, but it never contrasts itself with the sibling tools exchange_rate or unit_convert, leaving the agent to infer which one to pick.
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?
'按最新或指定日期汇率' implies the date-optional behaviour and the worked example shows the call shape, so usage is implied rather than stated. There is no explicit when-to-use rule and no exclusion against the sibling tools exchange_rate and unit_convert, which an agent could easily confuse with this one.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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