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

No annotations are provided, so the description carries the full burden of disclosing behavior. It discloses nothing: no side effects, no required context, no return value, and critically no how the tool receives input given the empty schema. The tool's observable sedanior is entirely opaque.

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, but it is under-specified, not concise - every word is merely a repetition of the tool name. There is no informative content to structure or front-load. This mirrors the 'Process' calibration case where brevity without substance scores 2.

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?

With no annotations, no output schema, an empty input schema, and a tautological description, the tool is entirely unusable for an agent. There is no way to know what inputs to pass, what the tool returns, or how it differs from x402-is-same-day and x402-is-same-month among hundreds of siblings. The definition is completely inadequate.

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?

Per baseline rule for 0-parameter tools, there is nothing for the description to document about parameters. However, the empty schema is itself puzzling for a tool named 'is-same-year' which presumably compares two values - the description does not clarify whether inputs come from conversation context or an alternative mechanism, so I deduct some credit from the baseline.

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 is a pure tautology - 'Is Same Year: Is Same Year' restates the tool's name and title without adding a single new fact. It fails to state the verb, the ressource, or what comparison is being performed. An agent learns nothing from it beyond what the tool name already conveys.

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?

There is no guidance whatsoever on when to use this tool. The context shows dozens of date-related sibling tools (x402-is-same-day, x402-is-same-month, x402-date-diff, x402-days-beween), yet the description offers no differentiation or selection criteria - not even a hint that it compares two dates/years or takes inputs.

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