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

No annotations are provided, so the description carries the full behavioral burden. It usefully discloses the 1-credit cost and the formatting modes, but it does not describe error behavior, whether currency conversion is performed, or what the output looks like.

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 plus a short cost note. Every element is relevant and there is no unnecessary wording.

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 tool is simple and the schema covers all parameters, but with no output schema the description should ideally state what formatting result is returned. It also mentions compact form even though no such parameter exists in the schema, which leaves a small completeness gap.

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 amount, locale, currency, and words. The description adds a use case for words (cheques and contracts), but it also mentions a compact form that is not represented in the schema, leaving some ambiguity without adding deeper meaning to the documented parameters.

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 specific verb and resource: formatting a money amount with currency, locale, compact form, and optional words. It is clear what the tool does, but it does not distinguish itself from nearby siblings such as calculate, convert_units, or fx_rates by explaining why an agent should choose this formatter over those tools.

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 gives an implied use case for the words option, noting it is for cheques and contracts, and mentions compact form. However, it does not state when to use this tool rather than currency-conversion or calculation siblings, nor does it give explicit exclusions or prerequisites.

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