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. It simply states the output but does not explain that the eight input parameters appear irrelevant or are discarded, nor does it clarify whether they affect the result. This is a significant transparency gap for a tool with a non-obvious input schema.

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 fragment with no wasted words, and the core output is front-loaded. It earns its place, though it is arguably under-specified given the complex input schema, which prevents a 5.

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?

A simple timestamp tool with no parameters would be complete with this description, but the presence of eight apparently irrelevant parameters makes the description inadequate. There is no output schema and no explanation of how the inputs relate to the tool, leaving the agent confused about whether to pass parameters and what effect they have.

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 already provides a description for every parameter, so the baseline is 3. The description itself adds no parameter information, but it does not contradict the schema. However, the schema descriptions reference behaviors like 'shape check' and 'discarded after the call' that are unexplained relative to the UTC timestamp purpose, so the description does not compensate for the confusion.

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 output and resource, distinguishing this from sibling tools like 'timezone' or 'iana-zones' by specifying UTC and timestamp. However, it lacks a verb and does not mention the existence of input parameters, so it is not a full 5.

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?

There is no guidance on when to use this tool versus alternatives such as 'timezone' or 'iana-zones'. No context, exclusions, or alternative routing is provided, leaving the agent to infer usage purely from the name.

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