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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds genuine context beyond that: data is fetched live from the spot feed and changes every minute, so results should not be cached or treated as stable — useful for an open-world, time-sensitive read.

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?

Two short sentences, front-loaded with what the tool returns and followed by freshness behavior. "Live" and "Read now from the spot feed" overlap slightly, but the second sentence still earns its place by explaining the minute-level volatility.

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 single optional parameter, read-only tool with no output schema, the description does the necessary work: it defines the ratio, enumerates the returned price forms, and notes live sourcing. It lacks only explicit sibling routing, which is the one gap an agent might still need.

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% with a single well-documented currency parameter including examples and a default, so the baseline of 3 applies. The description's "in any currency" weakly confirms the parameter's breadth and that it applies to both per-ounce and per-gram outputs, but adds no format or validation detail beyond the schema.

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 names the specific resource and even defines the metric ("ounces of silver one ounce of gold buys") and what else is returned (spot prices per troy ounce and per gram). It does not explicitly route away from the silver-focused siblings like get_silver_price_per_gram or calculate_silver_value, so the differentiation is implicit rather than stated.

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?

"Read now from the spot feed; the ratio moves every minute" conveys that this is a live, non-cached lookup, which implies real-time use cases. However, there is no explicit statement of when to prefer this over get_silver_price_per_gram or the value calculators, and no exclusions or preconditions are given.

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