currency_code

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

With no annotations, the description adds behavioral details: non-standard 160-bit codes pass through, and it works offline. However, it does not specify return format, input validation rules, or error handling, which would improve transparency.

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 sentences, no filler. The first sentence immediately states the core function, and the second adds important edge-case behavior. Every word 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?

Given the tool's simplicity (one parameter, no output schema), the description covers conversion direction, formats, and pass-through behavior. It is missing explicit mention of the return value, but the overall context is sufficient for a simple conversion tool.

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 parameter 'input' is described in the schema as 'a 3-char code or a 40-hex currency', which is clear. The description adds nuance about non-standard codes passing through, enhancing understanding beyond the schema. Schema coverage is 100%, so the baseline is 3, but the extra context justifies a 4.

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 converts between 3-char ISO codes and 160-bit/40-hex currency formats, using specific verbs ('Convert') and resources ('currency'). It also distinguishes from siblings, as no other sibling tool performs currency conversion.

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 implies usage for currency code conversion but does not explicitly state when to use it or mention alternatives. Since no sibling tool overlaps, the lack of explicit guidance is acceptable but not ideal.

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