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

The description discloses that the payloads are signed and include content_hash and MiCA Art.36 context, which is useful behavioral information beyond a simple price response. However, with no annotations provided, it does not mention whether the operation is read-only, potential rate limits, or any error handling, leaving some burden unmet.

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 two sentences. The first states the core function, and the second adds relevant output details (signed evidence, content_hash, MiCA context). Every word earns its place, and the 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 zero-parameter tool, the description covers the main purpose and key output characteristics: two metal prices, the ratio, and signed evidence with content_hash and MiCA context. While no output schema exists, the description provides enough about return values to be useful, though it could specify the exact response shape.

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 the schema fully covers any input needs. The description correctly omits parameter details, and the baseline for 0 params is 4. No additional parameter semantics are needed.

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 explicitly states the tool returns live gold (XAU) and silver (XAG) prices in a single call, and mentions the gold/silver ratio. This clearly distinguishes it from sibling tools like reserve_gold and reserve_silver, which likely return individual metals.

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 phrase 'in one call' implies using this tool when both gold and silver prices are needed together, but it does not explicitly compare to alternatives or state when not to use it. No exclusions or alternative tool names are given, leaving usage guidance implicit.

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