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

With no annotations, the description carries the behavioral burden. 'Current UTC timestamp' implies a read-only, side-effect-free call that returns a time value, but it does not clarify that all schema parameters are irrelevant or discarded, nor does it specify the timestamp format.

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 three words and contains no filler; the key information is front-loaded. For a trivial zero-required-parameter tool, this is appropriately concise.

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?

The description does not explain that the nine optional schema parameters can be ignored, and it leaves the output format unspecified. Given the unusually broad schema, an agent could reasonably wonder if one of those parameters changes the behavior.

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?

Because schema description coverage is 100%, the baseline is 3 even though the tool description adds no parameter-level meaning. The schema already documents every parameter, with several explicitly marked as discarded.

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 phrase 'Current UTC timestamp' clearly communicates that the tool returns the current UTC time, even though it is a noun phrase rather than an explicit action. It does not distinguish this from sibling time tools like timezone or iana-zones beyond the UTC qualifier.

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 about when to choose this tool over the other time-related siblings, and no note that it requires no meaningful arguments. It is not misleading, but it leaves the selection decision entirely to inference.

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