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

With no annotations, the description carries full responsibility for behavioral disclosure. It simply says 'Current UTC timestamp' but fails to mention that all nine parameters are accepted and discarded. This is a significant hidden behavior that could mislead an agent into thinking the tool processes those inputs. The schema descriptions hint at discarding, but the tool description itself does not.

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, focused sentence with no fluff. It is front-loaded with the core purpose. This is exemplary conciseness, though it may be too minimal given the tool's complexity.

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 9 parameters but no required ones, and the description does not explain why they exist or that they are ignored. It also does not specify the output format (e.g., ISO 8601, Unix epoch). Given the simplicity of the tool, this is incomplete—an agent might wonder whether to pass a parameter and what the returned timestamp looks like.

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% coverage, with each parameter described (e.g., 'discarded after the shape check', 'no disk access'). The tool description adds no additional meaning about parameters, so the baseline of 3 is appropriate. However, the parameter descriptions themselves are informative enough for an agent to understand they are not used for time computation.

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 states the tool returns the current UTC timestamp, which is a clear and specific purpose. It distinguishes from the sibling 'timezone' (which likely converts times) and 'iana-zones' (which lists zones). However, it does not explicitly mention that all input parameters are ignored, which could confuse an agent about the tool's actual scope.

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 like 'timezone' or 'iana-zones'. The description does not mention prerequisites, limitations, or use cases. An agent would have no idea whether to call this for time conversion or zone listing.

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