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

No annotations are provided, so the description carries the full burden. It does not disclose whether the tool has side effects, requires any arguments, or ignores the supplied parameters. While a timestamp lookup is implicitly non-destructive, the description should state that all parameters are ignored and no arguments are needed.

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, concise sentence with no filler. It front-loads the essential information and is easy to parse.

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 timestamp tool, the description conveys the main purpose, but it omits the output format (e.g., ISO-8601 string, Unix seconds) and does not address the irrelevant parameters. Since there is no output schema, this missing format detail leaves some ambiguity for an agent.

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 schema has nine optional parameters with descriptions, but these descriptions are largely unrelated to returning a UTC timestamp. The tool description does not clarify that these parameters are irrelevant or that the tool can be called with no arguments. This risks an agent passing an unnecessary parameter such as 'zone'.

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' is precise and clearly states the tool's core function. The tool name reinforces this, leaving no ambiguity about what is returned.

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 given on when to use this tool versus sibling tools like timezone or iana-zones. It is clear from the description that it returns the current UTC time, but the description does not explicitly state the intended use case or contrast it with alternatives.

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