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

No annotations are provided, so the description carries the full behavioral burden, yet it discloses nothing about computation semantics (e.g., whether the result is signed, exclusive or inclusive of endpoints), error behavior, or output shape. Zero added value.

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?

It is short, but the repetition 'Days Until: Days Until' is padding rather than concision; the single sentence earns nothing and is not front-loaded with any useful information.

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 two-parameter date tool with no annotations, no output schema, and no required-parameter guidance, the description is completely inadequate. An agent cannot determine what the tool returns or how to correctly supply its ambiguous parameters.

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 description coverage is 100%, so the baseline is 3 per the rubric. However, the schema descriptions themselves are near-meaningless ('Date to process', 'Target to process'), and the tool description adds no clarification of how 'date' and 'target' relate or what format is expected.

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 Until: Days Until' merely restates the tool name with no verb, no explanation of what is computed, and no differentiation from the many sibling date tools such as x402-days-between, x402-days-since, or x402-countdown.

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 on when to use this tool versus alternatives like x402-days-between or x402-time-until, nor any mention of prerequisites or context. The agent is left to infer everything from the name alone.

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