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

With no annotations, the description carries the full burden of behavioral disclosure, but it only says 'Current UTC timestamp.' It does not state that the tool performs no side effects, requires no meaningful arguments, or that the listed parameters are ignored or discarded. The parameter descriptions hint at discarding, but the tool-level description leaves this behavior opaque.

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 short, front-loaded phrase with no wasted words. It is appropriately concise for a trivial tool, though it is so terse that it misses important behavioral 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 a surprisingly complex schema with 9 optional parameters, no annotations, and no output schema, the description is incomplete. It does not explain whether the parameters affect behavior, how the output is formatted, or why such a simple tool accepts these inputs. An agent would likely be confused about whether to pass 'city' or 'json' even though neither is needed.

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% description coverage, so the baseline is 3. The tool description adds nothing about parameters, but because each parameter already has a meaningful, if odd, description, the schema itself carries the semantic load. The description could have clarified why parameters like 'feed' and 'json' appear for a UTC timestamp tool.

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 indicates the tool's purpose: returning the current UTC timestamp. It is specific enough to be distinguished from most sibling tools by the resource and value it exposes, though it lacks an explicit verb and does not explicitly differentiate itself from the sibling 'timezone'.

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 also does not mention that all 9 input parameters are optional and irrelevant to the timestamp output, leaving the agent without direction on how to invoke it appropriately.

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