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

No annotations are provided, so the description carries the full burden. It discloses only the payment model (5 free calls per signed wallet), which is genuinely useful, but says nothing about whether all three inputs are optional, what defaults apply when omitted, or what the computation produces.

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?

It is short and front-loaded, but the brevity comes from under-specification rather than economy — the one clause about the ratio itself conveys no information, so the sentence does not earn 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 three-parameter financial calculation with no annotations, no output schema, and fully undocumented inputs, the description omits everything an agent needs to call it 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?

Schema description coverage is 0% and all three parameters (return, stddev, riskFree) are typed as strings with no explanation. The description adds nothing, leaving it unclear whether "return" is a series of returns or a single mean, or what units riskFree expects.

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?

"Sharpe Ratio: Ratio of sharpe" restates the tool name in circular form without stating what is computed, from what kind of input, or what the result represents. The only distinguishing content is the pricing note, not the purpose.

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 guidance on when to use this versus the near-identical sibling x402-sharpe, x402-stddev, x402-returns, or x402-risk-related tools. The agent is left to infer usage from the name alone.

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