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

There are no annotations, so the description must carry the burden of behavioral disclosure. It does not state that all input parameters are discarded/ignored, nor does it confirm that this is a stateless, side-effect-free operation. The schema hints at 'discarded' behavior, but the description itself is silent.

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 exceptionally brief and front-loaded, with no filler or redundant wording. Every word contributes to the core meaning.

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?

Despite the tool being simple, the description ignores the substantial input schema and never explains that the parameters are irrelevant to the result. With no annotations and no output schema, an agent would be confused about how the nine inputs relate to 'Current UTC timestamp.'

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 provides descriptions for all nine parameters, so schema coverage is 100%. The description adds nothing about parameters, but the baseline of 3 applies because the schema already documents each parameter.

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 'Current UTC timestamp' clearly states the tool's core behavior: it returns the current time in UTC. It is specific about the resource (UTC timestamp) and sets it apart from timezone-related tools, though it doesn't explicitly name a sibling.

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 gives no guidance about when to use this tool versus alternatives like timezone or iana-zones. It also does not clarify why the input schema contains nine seemingly unrelated parameters or whether they should ever be provided.

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