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

Annotations already establish read-only and idempotent behavior, lowering the burden on the description. The description adds valuable context: it uses Wesalna's daily cached metal price snapshot unless the caller overrides it. This makes the data source and default behavior explicit. There is no contradiction with the annotations.

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 with no filler and front-loads the core verb and the three calculation modes. The first sentence is dense with interrelated rules, but every clause carries information an agent needs. It remains appropriately sized for a 15-parameter tool.

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 has no output schema, and the description never states what the result contains – such as the amount due, whether nisab was met, or a breakdown by category. While inputs and calculation rules are covered thoroughly, the missing return-shape information is a significant gap given the absence of an output schema.

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 the baseline is 3. The description adds meaningful calculation semantics beyond the schema: the 2.5% rate above gold or silver nisab, conversion of karat weight to pure gold against the 85-gram threshold, and the sa' weight per person for fitr. This enriches parameters like nisabBasis, pieces, and staple.

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 opens with a specific verb and resource – 'Calculate zakat' – then enumerates the three distinct calculation modes: money, gold, and zakat al-Fitr. It is the only zakat-related tool among its siblings, so there is no ambiguity about which tool to pick.

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 clearly explains when each mode applies: money for cash/savings/debts, gold for karat-weighted pieces, and fitr for per-person staple food. It also tells the agent that cached prices are used unless it supplies its own, which is useful guidance for customizing calls. It does not explicitly state exclusions, but no sibling tool competes for this purpose.

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