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

With no annotations supplied, the description carries the burden and does disclose useful context the schema cannot: it is a zero-side-effect constant lookup and it costs money after 5 free trial calls per signed wallet. It stops short of describing the response shape or what happens when the free quota is exhausted, which matters for an x402 paid endpoint.

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?

Three short sentences, front-loaded with what is returned, then the input requirement, then the pricing note. The 'Golden:' prefix merely restates the tool name and the emoji adds visual noise, but nothing is genuinely wasted.

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 trivial constant-returning tool with no parameters, no annotations and no output schema, the description covers what is returned, that nothing is required, and the payment model. The only gap is disambiguation from the duplicate sibling x402-golden-ratio.

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 tool takes zero parameters, so the baseline is 4. The sentence 'No input needed' confirms the empty schema and removes any doubt about whether a value must be supplied.

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 states a specific verb and resource ('Return the golden ratio') and even gives the value, so the agent knows exactly what comes back. It does not, however, distinguish this from the near-identical sibling x402-golden-ratio, leaving ambiguity about which constant tool to call.

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?

'No input needed' implies the tool can be called at any time for a constant, but there is no explicit when-to-use guidance, no mention of the overlapping sibling x402-golden-ratio, and no statement about when a computed ratio (e.g. from x402-golden-ratio) would be preferable.

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