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

With no annotations available, the description carries the full burden of behavioral disclosure. It states the expected output but does not reveal output format, side effects, or the fact that the listed parameters are discarded and have no lasting effect; only the parameter descriptions hint at this.

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 extremely concise and front-loaded, with no filler or repetition. While it is minimal, it communicates the core function directly and is appropriately sized for a trivial utility.

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 simple time utility, the description is minimally adequate, but it omits the output format and does not explain the unusual set of seven parameters in the main text. The schema compensates for parameter details, yet the lack of output-schema information leaves the return value partially unspecified.

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?

All seven parameters have detailed descriptions in the input schema, including notes like 'discarded after the shape check' and 'no disk access', so schema coverage is high. The main description adds no parameter context, but it does not conflict with the schema, so the baseline score of 3 is appropriate.

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 clearly communicates that the tool returns the current UTC timestamp, which is a specific and identifiable purpose. However, it does not explicitly differentiate itself from the sibling `timezone` tool or mention when UTC is preferred, so it falls short of full sibling differentiation.

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 provides no guidance on when to use this tool versus alternatives like `timezone`. There is no mention of exclusions, prerequisites, or how this tool differs from related utilities, leaving the agent without explicit decision-making context.

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