List supported commodity symbols

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

With no annotations provided, the description carries the burden of behavioral disclosure. It indicates the operation is read-only ('Returns') and lists the returned fields, but does not describe response format, pagination, error behavior, or data freshness. This is adequate but not comprehensive.

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: one sentence for purpose and returned fields, one sentence for usage guidance. No wasted words, and the key information is front-loaded.

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 tool with no parameters and no output schema, the description adequately covers the return values (category, default currency, unit) and usage context. It could be slightly more explicit about the response format (e.g., array of objects) and whether any authentication is needed, but overall it is complete enough for simple tool invocation.

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?

There are zero parameters, so schema coverage is trivially 100%. The baseline for 0 params is 4, and no parameter explanations are needed. The description adds value by explaining what the response contains, which is beyond the empty 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 clearly states the tool returns all supported commodity symbols with specific fields (category, default currency, unit). It distinguishes itself from sibling rate tools by focusing on listing symbols rather than retrieving prices or rates.

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?

It explicitly says to use this tool to look up a symbol before calling rate tools, providing a clear usage context relative to its siblings. However, it does not explicitly state when not to use it or name alternatives, which would make it a 5.

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