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

Annotations declare readOnlyHint: true, and the description aligns with that. It adds behavioral context by explaining the nullable premium_over_spot_bps and its null condition, and notes the tier requirement. It does not contradict annotations and provides useful extra detail beyond what annotations offer.

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 concise and well-structured: the first sentence states the core purpose and key distinction, the second covers parameter format, tier requirement, and documentation link. Every sentence carries necessary information with no fluff.

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 an output schema (though not shown) and the description covers the essential aspects: purpose, parameter format, tier requirement, and a docs link for sample responses. It also mentions a nullable field in the output. While it doesn't discuss error handling or unsupported countries, it is sufficiently complete for a simple read-only tool with one parameter.

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 input schema has only the 'country' parameter with zero description coverage, so the description fully compensates by specifying it is an ISO 3166-1 alpha-2 code and provides concrete examples (ID, IN, AE, JP). This adds meaningful semantic meaning beyond the bare schema definition.

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 clearly states the tool returns 'latest per-country physical dealer/retail gold prices' with a specific verb ('Return'), a resource ('physical dealer/retail gold prices'), and scope ('per-country'). It also distinguishes itself from spot-derived arithmetic, making it distinct from sibling tools like get_spot_price.

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 implies usage context by contrasting with 'NOT spot-derived arithmetic' and specifying per-country data. It mentions a tier requirement ('Requires the Physical tier or higher') but does not explicitly name alternative tools or state when not to use it. The context is clear but exclusions are not stated.

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