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

With no annotations provided, the description carries the full burden of behavioral disclosure. It doesn't mention that the tool accepts 9 parameters that are mostly discarded, nor does it explain what the output format looks like. The description is too minimal to convey the tool's actual behavior beyond returning a timestamp.

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 at just three words. It's front-loaded and to the point, though it may be too sparse to be genuinely helpful. It earns points for efficiency but loses some for not adding context.

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 tool has 9 parameters, no output schema, and no annotations, the description is inadequate. An agent cannot tell why the tool accepts parameters like 'ref', 'url', 'city', etc., or what the return value looks like. The description needs to explain that these parameters are accepted but ignored, and what the output format is.

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?

Schema description coverage is 100%, so the schema already documents all 9 parameters. The description adds no parameter-specific meaning, but the baseline of 3 applies because the schema does the heavy lifting. However, the description doesn't clarify why a UTC timestamp tool accepts parameters like 'city' or 'feed', which could confuse an agent.

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's purpose with a specific verb and resource. It distinguishes itself from the sibling 'timezone' tool, which likely deals with timezone conversions, while this tool simply returns the current UTC 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?

The description provides no guidance on when to use this tool versus alternatives like 'timezone' or 'iana-zones'. It doesn't mention that the tool accepts various parameters that are discarded, nor does it clarify that it's a simple utility for getting the current time.

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