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

With no annotations provided, the description carries full responsibility for behavioral disclosure. It specifies the output format (ISO 8601) and timezone (UTC), which are the key behavioral traits. It does not mention error behavior, but with zero parameters, there are no failure modes to disclose. The description is accurate and adds sufficient context.

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 front-loads the action and includes all necessary details (format and timezone) with zero waste. It is structured optimally for an agent to parse quickly.

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 the zero parameters, no output schema, and simple purpose, the description is fully complete. An agent can invoke the tool correctly without any additional information. The description covers what it does and what it returns.

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 tool has zero parameters, so the baseline score is 4 as per rubric. The description does not need to explain parameter semantics because there are none, and the schema is empty. The description correctly implies that no input is required.

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 a specific action ('Returns') and a specific resource ('current server time') with format and timezone. The siblings 'add' and 'echo' are completely unrelated, so there is no ambiguity or need for differentiation.

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 tool's purpose is self-evident, providing clear context for when to use it. There are no similar alternatives among siblings, so no exclusions or when-not guidance is required. However, it does not explicitly state conditions for use beyond what the description implies.

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