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

With no annotations, the description carries the full burden, but it only describes the output. It does not disclose whether the tool has side effects, whether all parameters are ignored, or how the 9 unrelated input parameters relate to the tool's behavior.

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 with no filler. It is appropriately front-loaded, though it omits context that might be expected given the large schema.

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 optional parameters and no output schema or annotations, yet the description provides no guidance on what to pass or what return format to expect. The mismatch between the simple description and the broad input schema leaves an agent uncertain about 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?

Schema description coverage is 100%, so the schema already documents each parameter. The description adds no parameter-level meaning, but the high schema coverage establishes the baseline of 3.

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 output with a specific verb and resource. It is distinct from siblings like timezone or iana-zones, but it does not explicitly call out that 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 description implies use when a current UTC timestamp is needed, but it gives no explicit when-to-use or when-not-to-use guidance. It does not mention alternatives such as timezone for localized time or iana-zones for zone names.

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