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

Annotations already declare readOnly, idempotent, non-destructive and open-world; the description usefully adds that pricing is at the live spot price (dynamic, network-dependent results) and that the output carries a disclaimer about melt vs. retail/buyback. It stops short of covering failure modes such as unsupported currency codes or karat/unit mismatches.

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?

Three tight sentences with the core computation front-loaded and the disclaimer last. The opening sentence is densely packed with four input mentions, but no sentence is filler.

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?

For a read-only calculator with fully described parameters and no output schema, the description is sufficient: it names the computation, the optional branch (dealer spread), and even hints at result content (buyer offer, disclaimer). Only edge-case behavior on invalid currency/unit input is left unaddressed.

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 unit aliases, karat range, currency format and spread math are all already documented in the schema. The description only adds that dealer_spread_percent yields a 'likely buyer offer' and that any currency is supported, which is a modest increment over the structured fields.

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 states a specific computation (melt value) from named inputs (weight, unit, karat) against the live spot price in any currency, which an agent can easily separate from price-lookup or unit-conversion tasks. It never names a sibling tool, so explicit differentiation is absent, keeping it at 4 rather than 5.

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?

Usage context is clear: value a physical gold item (ring, chain, bracelet, scrap), optionally with a dealer spread to approximate a buyer offer. It also sets a scope boundary by noting the result clarifies melt value is not retail or buyback price, but it gives no explicit routing to get_gold_price_per_gram or convert_gold_units.

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