system_list_currencies

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

With no annotations provided, the description carries full burden. It clearly explains that the tool is read-only, returns a list with detailed field descriptions, and is cached for 24 hours, which sets expectations about data freshness. No contradictions or omissions are present.

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 sections for return fields and common use cases. It is somewhat lengthy but uses bullet points effectively. Every sentence adds value, though some repetition could be trimmed.

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?

The description explains all return fields in detail, mentions caching behavior, and provides common use cases. It is comprehensive for a zero-parameter read tool, especially given no output schema is provided.

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?

The input schema has zero parameters (100% coverage), so baseline is 4. The description adds value by explaining the output fields and their semantic meaning, which is helpful beyond the empty schema.

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 explicitly states the tool returns a list of supported currencies and exchange rates, listing specific fields like currency codes, symbols, names, exchange rates, active flag, and decimal precision. It distinguishes itself from siblings by being a read-only system tool for currency data.

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 use cases such as getting supported currencies before creating deals, validating currency codes, and understanding exchange rates. It mentions the caching behavior, which implies that for real-time updates, alternative tools might be needed, but doesn't explicitly state when not to use it or list alternatives.

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