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, and it discloses nothing: not the reference point for 'since' (current date vs. another date), not the return unit, not timezone handling. This is a total absence of behavioral context.

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 text is extremely short with no wasted words, but this is under-specification rather than conciseness — the repetition of the title conveys zero information and there is no front-loaded explanation of the operation.

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 tool with no annotations and no output schema, the description should at minimum explain what is subtracted from what and what the output represents. It does none of this, leaving the agent unable to invoke the tool with confidence.

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?

With a single parameter and 100% schema description coverage, the baseline is 3 per the rubric. The schema's own label ('Date to process') is generic and does not specify format, but the description adds nothing on top of it, so no credit above baseline is warranted.

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 tautology: 'Days Since: Days Since' merely restates the tool name with no verb, resource, or scope. An agent cannot tell what is being computed (days since an event? since today? since a given date?) or how this differs from siblings like x402-days-between, x402-days-until, or x402-days-since variants.

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 when-to-use guidance, no mention of alternatives, and no conditions under which this tool should be preferred over the many date-difference siblings. The description provides no routing information at all.

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