Convert an amount from one currency to another using exchange rates; provide source and target currency codes, with optional amount and API key.
Convert an amount from one currency to another.
| Name | Required | Description | Default |
|---|---|---|---|
| to | Yes | Target currency code (e.g. EUR) | |
| from | Yes | Source currency code (e.g. USD) | |
| amount | No | Amount to convert (default 1) | |
| api_key | No | Optional for conversion (uses latest rates if omitted) |
Changes observed during successful MCP inspections.
v0.1.9v0.1.5Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly, idempotent, openWorld, and non-destructive behavior. The description adds no further behavioral context, such as rate source, freshness, or auth implications, so it contributes little beyond the annotations.
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 front-loaded sentence with no wasted words. Its brevity is efficient, though it borders on under-specification rather than ideal conciseness.
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 four-parameter conversion tool with full schema coverage and annotations, the description is adequate but incomplete. It does not clarify the source of exchange rates, freshness, or behavior when api_key is omitted beyond what the schema already says.
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 the schema already documents all four parameters. The description does not add meaning beyond that, which is acceptable at the baseline for fully covered schemas.
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 clear verb and resource: converting an amount between currencies. It does not distinguish this tool from sibling converters such as frankfurter_convert or forex_convert, so it falls short of a 5.
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?
There is no guidance on when to use this tool versus alternatives, no mention of prerequisites, and no exclusions. An agent must infer usage purely from the tool name and schema.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.