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

With no annotations present, the description must carry the behavioral disclosure burden. It does not mention that the many accepted parameters are discarded or irrelevant, nor does it specify the output format. The schema hints at discarding, but the description itself adds no behavioral transparency.

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 a single short sentence with no wasted words, making it highly concise and front-loaded. However, it is so minimal that it omits important usage context, so it is not a perfect score.

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 conceptually simple, the 7-parameter schema and lack of output schema make the description incomplete. It does not clarify the output format, whether arguments are ever meaningful, or how this tool relates to the timezone sibling. An agent could call it, but with avoidable uncertainty.

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 seven parameters, so schema coverage is effectively 100%. The description adds no parameter-level information, but the baseline of 3 applies because the schema already documents each parameter's role.

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 identifies that the tool returns the current UTC time, and this distinguishes it from siblings like timezone or iana-zones. It lacks an explicit verb like 'returns', but the resource and intent are unambiguous.

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 use this tool versus alternatives such as timezone or when to pass parameters. The description does not state that all inputs are optional or ignored, leaving the agent to infer usage from the schema.

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