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, and it reveals nothing. It does not state what the tool returns, whether it uses the current year, how leap years are handled, or what the output format is.

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 only six words, but this is under-specification rather than genuine conciseness. The repetition 'Days In Year: Days In Year' wastes its short length on a tautology instead of substantive content.

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 date utility with no annotations, no output schema, and a large field of confusable siblings, the description provides essentially no information. An agent cannot determine what input the tool expects, what it outputs, or which of the many date tools it competes with.

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 schema has 0 parameters with 100% coverage, so per the rubric the baseline is 4 since there is nothing for the description to document. However, the tool name implies a year input is needed, and the description does nothing to clarify how the year is determined without parameters, which is a notable gap.

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 'Days In Year: Days In Year' is a pure tautology that merely restates the tool name with no verb and no resource clarification. It fails to distinguish this tool from many date-related siblings like x402-day-of-year, x402-days-in-month, and x402-weeks-in-year.

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?

The description provides zero guidance on when to use this tool versus the dozens of closely related date tools in the sibling list. No context, alternatives, or exclusions are mentioned, leaving an agent to guess how this differs from x402-days-in-month, x402-day-of-year, or x402-days-between.

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