format_currency

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

With no annotations, the description carries full burden. It discloses handling of the Unicode symbol transition and indicates input/output format but does not cover error behavior (e.g., invalid locale/currency), edge cases (negative amounts), or whether the operation is read-only. Some transparency is provided but gaps remain.

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 two sentences, tightly written with no redundancy. The key purpose and example are front-loaded, making it efficient for an agent to parse quickly.

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 4 parameters and no output schema, the description covers basic input/output and a notable behavioral detail (Unicode transition). However, it lacks explicit return type (string) and error scenarios, leaving some uncertainty. A more complete description would mention the string output and handle edge cases.

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 coverage is 100%, so baseline is 3. The description adds an example and mentions Unicode transition but does not elaborate on parameter semantics beyond what the schema provides. It confirms the output format but adds no new meaning per 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?

The description clearly states that the tool formats a number as an Arabic currency amount with correct symbol, grouping, and decimal precision. It provides a concrete example (1234.5 SAR -> '1,234.50 ر.س') and differentiates from siblings like format_number and spell_currency by specifying Arabic currency context.

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 Arabic currency formatting but does not explicitly state when to use this tool versus siblings like format_number (general formatting) or spell_currency (spelling out). No when-not or alternatives are mentioned, leaving the agent to infer context from the purpose.

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