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

No annotations are supplied, so the description carries the full behavioral burden, and it discloses nothing: not what the output format is, not how missing/invalid dates are handled, not whether it is a pure computation or a mutation.

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 it is not concise—it is under-specified. The duplicated 'Time Until: Time Until' consumes the entire body without conveying any information beyond the name.

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, and two ambiguously named parameters, the description should be doing heavy lifting. It provides nothing about behavior, inputs, or return shape, leaving an agent unable to call the tool confidently.

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 per the baseline the schema nominally documents both parameters. However, the schema text itself is thin ('Date to process', 'Value to process'), and the description adds nothing to disambiguate what 'value' means alongside 'date', so it sits at the baseline rather than above it.

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 the tool name repeated twice ('Time Until: Time Until'), which is a tautology rather than an explanation. It weakly hints at computing a remaining duration to a date, but states no verb, no input semantics, and does not distinguish it from siblings such as x402-days-until, x402-countdown, or x402-relative-time.

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 the many adjacent date/duration tools in the catalog. No prerequisites, no exclusions, no alternative named.

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