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

With no annotations provided, the description carries the full burden of behavioral disclosure, yet it only states that a 'calculation' occurs. It does not reveal the formula used (e.g., CAGR-style vs. compounded periodic returns), whether the result is returned as a decimal or percentage, how inputs are supplied given the empty schema, or how edge cases are handled.

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 short and the core phrase is front-loaded, but the 'Annualized Return:' prefix is redundant with the tool name and the body merely re-states it. It is compact without fluff, yet the content is so minimal that brevity reflects under-specification rather than disciplined editing.

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?

Despite the tool's simplicity (0 parameters, no nested objects), the description is a bare label with no output schema and no annotations to compensate. An agent cannot tell what inputs it must supply, what formula is applied, what the return format is, or how this differs from the many finance siblings, making correct invocation a matter of guesswork.

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 input schema has zero properties and 100% coverage, so there are no parameters for the description to document; per the rubric, 0 parameters earns a baseline of 4. The description adds nothing about how the agent should provide the values to be annualized, but this dimension concerns schema semantics, which are trivially complete.

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 'Annualized Return: Annualized return calculation.' is essentially a restatement of the tool name, adding only the generic verb 'calculation'. It identifies the financial concept but provides no specific method or formula, and it does nothing to distinguish this tool from closely related siblings like x402-cagr, x402-holding-period-return, or x402-returns, which all plausibly compute return measures.

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 whatsoever is given about when to use this tool versus alternatives. An agent facing the sibling cluster x402-cagr, x402-holding-period-return, x402-log-returns, x402-returns, and x402-monthly-to-annual receives no criteria to select this one, and no context about the intended input situation is provided.

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