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

No annotations are provided, so the description must disclose all behavioral traits. It only states the tool returns a timestamp, implying a read-only operation, but gives no detail on side effects, dependencies, or whether the parameters affect the output. The unrelated parameters are entirely unexplained, creating potential for misuse.

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 sentence, which is appropriately concise. However, it is under-specified to the point of being unhelpful; conciseness should not come at the expense of essential information. It does not front-load critical details like the return format or parameter relevance.

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?

With no output schema, no annotations, and four parameters that appear unrelated to the tool's purpose, the description is severely incomplete. An agent cannot determine what parameters to provide, what the output will look like, or how this tool differs from similar ones. This is inadequate for any realistic use case.

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?

While schema coverage is 100%, the parameter descriptions (e.g., 'HTTPS URL to normalize or cite') are completely disconnected from the tool's stated purpose of returning a UTC timestamp. The description adds no context about how these parameters are used, leaving the agent confused about what to pass. The baseline of 3 is not met because the description fails to integrate the parameters into the tool's function.

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 time in UTC. It is distinct from siblings like 'timezone' which likely deal with timezone conversions. However, it does not specify the return format (e.g., ISO 8601, Unix epoch), and the presence of unrelated parameters in the schema muddies the 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?

There is no guidance on when to use this tool versus alternatives such as 'timezone' or 'iana-zones'. The description does not mention exclusions or complementary tools, leaving the agent to guess from the name alone.

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