Convert an amount between two currencies using official ČNB rates. E.g., convert 100 EUR to CZK, or 50 USD to GBP (goes via CZK cross-rate). Optional date for historical conversion.
| Name | Required | Description | Default |
|---|---|---|---|
| to | Yes | Target currency ISO 4217 code. | |
| date | No | Optional ISO date for historical rates. Omit for latest. | |
| from | Yes | Source currency ISO 4217 code (e.g., "EUR", "USD", "CZK"). | |
| amount | Yes | Amount to convert. |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already provide readOnlyHint, so the safety profile is covered. The description adds valuable behavioral detail beyond the schema: the conversion 'goes via CZK cross-rate' and supports an optional date for historical rates. This explains how the tool works without repeating 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 two sentences: first states the core purpose, second gives examples and the cross-rate note. It is front-loaded, efficient, and contains no fluff. Every sentence earns its place.
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 read-only conversion tool with full schema and no output schema, the description is largely complete: purpose, examples, cross-rate behavior, historical option. It could mention the return format, but that's not critical for a simple conversion. Overall, it provides sufficient context for an agent to use it 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 covers 100% of parameters with descriptions, but the description adds meaning: it explains the cross-rate mechanic (from/to via CZK) and provides concrete examples. The `date` parameter is clarified as optional for historical conversion. This goes beyond the schema's basic ISO code descriptors.
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's function: 'Convert an amount between two currencies using official ČNB rates.' It includes specific examples (EUR→CZK, USD→GBP) and differentiates from sibling tools like get_rate and get_rates by emphasizing conversion of an amount rather than just fetching a rate.
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 provides clear context for when to use this tool (converting amounts between currencies, with optional historical date). It does not explicitly mention alternatives or exclusions, but the examples and purpose make it obvious this is the conversion tool, not a rate-lookup tool. A small gap: no explicit 'use get_rate for just rates' guidance.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
The three tools are mostly distinct: convert handles cross-currency conversion, get_rate provides a single currency's CZK rate, and get_rates lists all rates. However, get_rate without a code returns all rates, overlapping with get_rates, which could cause confusion if descriptions are not carefully read.
All tools follow a consistent lowercase verb-based naming convention: convert, get_rate, get_rates. The pattern is simple and predictable, with the plural 'rates' clearly distinguishing the bulk operation from the single-rate lookup.
With only 3 tools, the server is tightly scoped for its purpose of accessing ČNB exchange rates. Each tool serves a distinct, necessary function—conversion, single rate lookup, and full rate listing—without redundancy.
The tool surface covers the core domain completely: retrieving all rates, retrieving a single rate, and converting between currencies, including historical dates. No obvious missing operations for a currency exchange rate server of this type.