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, but it only states that the result is a current UTC timestamp. It does not mention output format, side effects, or that the nine listed parameters are effectively ignored; the schema hints at this, but the description itself does not.

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 concise and front-loaded with no filler words. However, it is under-specified relative to the nine-parameter input schema, so the brevity limits its usefulness as a standalone explanation.

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?

For a tool with nine optional parameters, no annotations, and no output schema, a four-word description is not sufficient. It fails to clarify that no arguments are required, what the timestamp format is, or how this tool relates to the sibling timezone-related tools.

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 baseline of 3 applies even though the tool description adds no parameter-level meaning. The per-parameter descriptions in the schema, such as 'discarded after the shape check' and 'no disk access', already communicate that these parameters are optional or no-ops, though the tool description does not reinforce this.

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' is essentially a restatement of the tool name 'utc-time' as a noun phrase. It does not use a verb or specify an action, and it does not differentiate the tool from siblings such as timezone or iana-zones.

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 gives no guidance on when to use this tool versus alternatives like timezone or iana-zones. There are no context cues, exclusions, or alternative-referencing statements for an agent to act on.

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