Current time

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

The description discloses the output format (ISO 8601) and the optional timezone behavior, which goes beyond the readOnlyHint annotation. While the read-only nature is already declared, the description adds useful behavioral details about the response, such as format and timezone handling.

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 that conveys all essential information without unnecessary wording. It is well-structured and directly states the tool's purpose and optional parameter.

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 tool that returns the current time, the description, combined with the schema, covers all necessary context: what the tool does, the output format, and the parameter's meaning and default. No additional information is needed for a user to invoke it 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 schema already provides a clear description for the timeZone parameter, including an example and default behavior. The tool description adds no new information about the parameter beyond what is already in the schema, so it does not enhance the parameter semantics beyond the baseline.

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's function: returning the current date and time in ISO 8601 format, with an optional timezone parameter. It is specific about the resource (current time) and the action (return), leaving no ambiguity about what the tool does.

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?

The description implicitly distinguishes this tool from the sibling knowledge-base tools (kb.search, kb.get, kb.add) by focusing on time retrieval. However, it does not explicitly state when to prefer this over alternatives, though the distinct purpose makes the use case obvious. A minor lack of explicit guidance prevents a perfect score.

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