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 discloses a paid-trial quota, which is genuinely useful context, but says nothing about input format, required permissions, accuracy assumptions, or response shape for a statistic tool.

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?

Short and front-loaded, but the emoji-annotated pricing clause pads a definition whose core ambiguity about the input is left unresolved.

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?

No annotations, no output schema, and one undocumented parameter with a name that conflicts with the description's stated input. For a computational tool this leaves the essential call contract unspecified.

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 coverage is 0% and the single parameter is named 'values', yet the description says the computation is 'from the sample standard deviation' — implying the caller supplies a standard deviation, not raw values. This mismatch leaves the agent unsure whether to pass raw data or a precomputed SD.

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 resource ('Computes the standard error of the mean') and even the input source ('from the sample standard deviation'). However, a near-identical sibling 'x402-standard-error-of-mean' exists and the description makes no attempt to distinguish between them.

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 when-to-use guidance, no alternatives named, no prerequisites. The only extra sentence concerns pricing ('5 free trial calls per signed wallet'), which is commercial info rather than usage guidance.

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