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

No annotations are provided, so the description carries full behavioral burden. It does disclose the payment/auth model ('5 free trial calls per signed wallet'), which is useful context, but it omits edge-case behavior such as what happens with an empty array or zero variance, and does not describe the response.

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?

Front-loaded with the operation and its definition in one compact sentence; nothing is padded. The trailing emoji/promo clause is slightly noisy but short.

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 simple single-parameter transform, the essentials are still missing: input encoding for the string parameter and the shape of the returned z-score array (no output schema exists to cover it). Combined with zero annotation coverage, the definition leaves an agent guessing on both ends of the call.

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 single parameter 'values' has 0% schema description coverage, so the description must compensate — but it only says 'an array.' It does not explain whether the value should be a JSON array literal, a comma-separated string, or something else, which is critical since the parameter is typed as a string.

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?

States a specific verb and transformation: converts an array to z-scores with zero mean and unit standard deviation, which is concrete and unambiguous. However, it offers no differentiation from the many near-identical siblings (x402-standardize, x402-standard-scale, x402-zscore, x402-zscore-array, x402-normalize-array), so an agent cannot tell which one to pick from the description alone.

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 z-score/standardize/normalize siblings, and no preconditions are stated. The only contextual line is a pricing note about free trial calls, which does not help tool selection.

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