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

No annotations are provided and the description discloses nothing about tool behavior, output format, side effects, or assumptions. Since there are no annotations to rely on, the description carries the full burden and fails entirely.

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?

Two short sentences appear concise, but they convey zero information; this is under-specification rather than effective conciseness. No useful detail is front-loaded or provided.

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 tool with no annotations and no output schema, the description should at least state what is measured, what reference point is used, and what kind of result is returned. The description is completely inadequate for an agent to decide when or how to use it.

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 input schema is empty with zero parameters and schema description coverage is 100%, so the schema already fully documents that no parameters are needed. The description adds nothing, but with zero parameters the baseline for parameter semantics is 4.

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 'Time Until: Time Until', which simply restates the tool name and provides no verb, resource, or behavior. It is a pure tautology and gives no indication of what computing 'time until' means or what input it relies on.

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 offers no guidance on when to use this tool or how it differs from related siblings such as x402-time-ago, x402-days-until, x402-relative-time, or x402-countdown. There is no implied usage context and no mention of alternatives.

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