get_metal_prices

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

No annotations are provided, so the description carries the full behavioral disclosure burden. It adds the useful constraint that a Pro plan is required, and clarifies the unit of measurement (per troy ounce in USD). However, it does not disclose potential error behavior (e.g., invalid symbols), rate limits, or the exact response structure. Given the tool's simplicity, this is acceptable but not rich.

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 a single, front-loaded sentence that delivers the core purpose and the critical plan requirement immediately. There is zero wasted wording; every element earns its place.

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 simple read operation with one optional parameter and no output schema, the description covers the essential aspects: what the tool does, the unit of measurement, the metals included, and the plan constraint. It does not mention error handling or return format, but given the low complexity and lack of an output schema, those are minor omissions. The description is sufficiently complete for an agent to call the tool correctly.

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?

The schema already describes the 'symbols' parameter fully (comma-separated codes, omit for all four), and schema coverage is 100%. The tool description does not add any parameter-specific information beyond what the schema provides, so it meets the baseline for high coverage without adding extra semantic detail.

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?

States a specific verb ('Get') and resource ('precious-metal prices per troy ounce in USD'), and enumerates the exact metals and codes. This clearly distinguishes it from the sibling currency, stock, and crypto tools, so an agent can immediately recognize its domain.

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 makes the domain obvious and mentions the Pro plan requirement, which sets an explicit condition for use. However, it does not explicitly name alternatives or say 'use this for metals, use get_crypto_rates for crypto', but given the clear resource scope, the usage context is effectively unambiguous. The main gap is no guidance on when to omit the symbols parameter vs. specifying it, though that is covered by the schema.

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