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

No annotations are provided, so the description must carry the full behavioral disclosure burden. The schema reveals that all parameters are 'discarded after the shape check' and that 'path' involves 'no disk access', but the description itself gives no hint that inputs are ignored or that the tool performs any validation. This is a significant behavioral gap for a tool with side-effect-like parameter processing.

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, but that brevity becomes under-specification given the tool's unusual parameter list. It is front-loaded and wastes no words, yet it omits necessary context about parameter behavior, so it does not fully earn its place as a standalone explanation.

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?

The tool has seven parameters, no output schema, no annotations, and a description that fails to explain how parameters relate to the output or why they exist. An agent cannot determine what arguments to supply, whether validation is performed, or what format the timestamp takes, making the description inadequate for correct invocation.

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 description adds no parameter semantics, but the input schema provides detailed descriptions for all seven properties, including explicit statements that values are discarded. With high schema description coverage, the baseline of 3 is appropriate; the tool description itself contributes nothing beyond what the schema already states.

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 resource (UTC timestamp) and the operation (retrieving current time), making the tool's fundamental purpose obvious. However, it does not explain why the tool accepts seven unrelated-looking parameters, which creates ambiguity about whether the tool does more than just return the time.

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 siblings like 'timezone' or when the parameters are meant to be used. A sibling 'timezone' exists, implying utc-time is for the current UTC moment while timezone may handle conversions, but this is left entirely to inference.

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