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

With no annotations, the description carries the full burden of behavioral disclosure. It states the output but does not mention that all seven input parameters are effectively discarded or irrelevant, nor does it clarify side effects or return format. The unrelated schema makes this omission more confusing.

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, front-loaded sentence with no fluff. It earns its place, though it is arguably too terse to address the confusing schema.

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 tool is simple, but the description fails to reconcile the seven unrelated input parameters with its stated purpose. There is no output schema and no explanation of how parameters factor into invocation, leaving an agent uncertain about what arguments, if any, to pass.

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 already documents all seven parameters with descriptions, including their 'discarded' behavior, so the schema coverage is high. The description itself adds no additional parameter semantics, which is acceptable given the baseline of 3 for schema-covered parameters.

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 returns the current UTC time, so the core purpose is identifiable. However, it lacks a verb, does not distinguish this tool from sibling time-related tools like timezone or iana-zones, and the input schema contains seven unrelated parameters that muddy the apparent purpose.

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?

No guidance is provided about when to use this tool versus alternatives such as timezone or iana-zones. The description gives no context for selection, no exclusions, and no indication that the listed parameters are irrelevant for typical use.

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