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

No annotations are provided, so the description must disclose behavioral traits. It only says 'Current UTC timestamp' and does not explain that the tool is read-only, that parameters are discarded or used only for shape checks, or that the output is unaffected by the parameters. This lack of disclosure could lead an agent to assume the parameters influence the result.

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 sentence with no wasted words. It states the core purpose directly and front-loads the primary function. While it is minimal, it earns its place by clearly identifying what the tool does without verbosity.

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?

Given that there are 9 parameters, no output schema, and no annotations, the description is severely incomplete. An agent does not know that all parameters are optional and discarded, that the tool is read-only, or what the return format is. The tool's behavior and the role of its parameters are not explained, making it difficult to call correctly.

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 has 100% description coverage, with each parameter described individually (e.g., 'discarded after the shape check'). The tool description itself adds no parameter semantics, but since the schema already documents them well, the baseline of 3 is appropriate. It does not compensate for the missing context about how parameters relate to the output.

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 states the tool returns the current UTC timestamp. It is specific and not a tautology, but it does not differentiate from sibling tools like 'timezone' or 'iana-zones' which may also return time-related data. It leaves the agent to infer which tool to pick based on the name alone.

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 on when to use this tool versus alternatives. The description does not mention any exclusions, prerequisites, or mention of the 9 parameters and their role in validation. An agent cannot determine when this tool is the right choice over siblings like 'timezone' or 'calc-eval'.

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