format_currency

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

No annotations provided, so the description carries full burden. It explains that formatting respects locale for symbol position and separators, with an example. However, it does not disclose edge cases like negative amounts or large numbers, or the exact return type (string implied). Adequate but not thorough.

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 concise sentences plus an example. No wasted words. Purpose and usage are front-loaded. Every sentence contributes meaningful guidance.

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 3-parameter tool with no output schema, the description is nearly complete. It covers purpose, usage guidance, behavioral details, and an example. Missing explicit return type but that is inferred from the example.

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 0%, so the description must add meaning. It explains how parameters (amount, currency, locale) affect output via the example and mention of locale rules. It adds value beyond the schema by illustrating behavior, though each parameter is not individually described.

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 formats a money amount per locale expectations, with a specific verb ('format') and resource ('money amount'). The example and context distinguish it from sibling tools (holidays, address, date, tax, phone), which are unrelated.

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?

Explicitly says 'USE THIS whenever you show a price/total to a user or put one in an email, invoice, or report.' It defines when to use but does not mention alternatives or when not to use, though the context makes it clear.

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