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

With no annotations, the description carries the full behavioral disclosure burden. It does not mention that all input parameters are ignored or discarded, what timestamp format is returned, or that the operation is read-only. The schema notes that some parameters are 'discarded,' but the tool description itself adds no behavioral context.

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 efficient phrase with no filler, earning a strong conciseness score. It is slightly too terse and lacks a verb, but it is not bloated.

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 tool with no output schema and no annotations, the description should clarify the return format and behavior, especially given an input schema with seven seemingly unrelated parameters. The phrase 'timestamp' is ambiguous (Unix vs. ISO 8601), and the tool description does not explain why such parameters exist or how they relate to the UTC time output.

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 descriptions in the input schema, so schema coverage is high. The tool description adds no parameter-level meaning, but the schema already documents each parameter's role and discard behavior, yielding the baseline score of 3.

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 the tool's output: the current UTC time. However, it uses a noun phrase rather than a verb phrase, and it does not explicitly distinguish itself from the sibling 'timezone' tool, so it is clear but not fully differentiated.

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 'iana-zones.' The description states only what the tool returns, not when it should be selected or when it should be avoided.

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