Zakat calculator

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

Annotations already cover the safety profile (readOnly, idempotent, closed-world), and the description adds genuinely useful behavior: no network fetch (so price inputs are mandatory in practice), the karat conversion rule, and that the output is an estimate rather than a ruling. It stops short of saying what happens when required prices are omitted 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?

Dense but every clause carries information — asset list, deduction, nisab, karat, price-input requirement, disclaimer. Front-loaded with the core formula. Minor deductions for being one unbroken block and for the trailing web-version URL, which does not help an agent invoke the 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?

With 13 parameters and no output schema, the description should indicate what comes back (zakat due, nisab applied, whether the threshold was met) and how missing prices are handled. It covers inputs and domain rules well but leaves the return contract and error behavior unstated, which is a meaningful gap for a zero-required-parameter tool.

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, but the description earns more: it explains the nisab thresholds (85 g pure gold default, or 595 g silver), how karat 24/22/21/18 converts gross grams to pure gold, and why goldPricePerGram/silverPricePerGram are required. That is real meaning beyond the per-field schema text.

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?

Opens with a precise verb-resource framing: 2.5% of net zakatable wealth, enumerating exactly which assets count (cash, bank, investments, trade goods, receivables, gold/silver) and which are deducted (debts due now). This is unmistakably distinct from every calc_* sibling, and an agent knows immediately what computation is being performed.

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?

States a critical usage constraint explicitly: the caller must supply today's gold/silver price per gram because 'nothing is fetched from the network' — this prevents an agent from calling it expecting live prices. It also frames the result as an estimate requiring scholarly consultation. It does not name when-not-to-use or an alternative tool, but no sibling overlaps this domain.

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