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 cost ($0.003 per call) and payment rail (USDC on Base), which is real context an agent cannot get from structured fields, but says nothing about validation behavior, error cases, or what the response contains.

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?

A single compact sentence with the core purpose front-loaded and no filler. The trailing parenthetical mixes conversion rate, price, and payment network, which is slightly overloaded but still tight.

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?

With 0% schema coverage, no annotations, no output schema, and an undocumented 'number' parameter, the description leaves an agent unable to invoke this correctly beyond passing a bare amount. Direction of conversion and accepted unit values are the critical missing pieces.

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% across three parameters, and the description does not compensate: it never explains that 'unit' selects conversion direction, nor what 'number' is for, nor what type 'amount' takes. The rate constant is helpful domain knowledge but does not map to any parameter.

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?

States a specific verb and resource ('Convert an amount between Iranian rial and toman') and even supplies the conversion constant (1 toman = 10 rial). No sibling tool in the fa_* list performs currency conversion, so it is trivially distinguishable from the validators and text utilities around it.

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?

There is no when-to-use guidance, no statement of which direction the conversion runs, and no indication of what values the 'unit' parameter accepts. The only implied usage is the verb itself, with nothing about exclusions or prerequisites.

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