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

No annotations exist, so the description carries the full burden. It does add genuinely useful operational context — per-call cost of $0.005 in USDC on Base — which the schema cannot express. However it says nothing about the output format (string of words?), default unit behavior, or handling of non-numeric input.

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 front-loaded sentence with the core purpose first and the cost note as a parenthetical. No filler, though the parenthetical pricing could arguably live in a metadata field.

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, and no output schema, the description should explain the parameters and the return shape. It leaves the amount/number ambiguity and the output format entirely unexplained.

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% for 3 parameters with no types declared for amount or number. The description's mention of 'rial or toman' hints at the unit parameter, but it never explains the distinction between 'amount' and 'number', which is a real source of agent confusion.

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 plus resource ('write a rial or toman amount in Persian words') and includes the Persian phrase (مبلغ به حروف) which aids recognition. It implies a distinction from siblings like fa_numberToWords and fa_rialToman but never names them explicitly.

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 no when-to-use or when-not-to-use guidance, and does not explain how this differs from fa_numberToWords (generic number-to-words) or fa_rialToman (currency conversion). The agent must infer the choice from tool names alone.

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