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

The description lacks any mention of side effects, return values, or error handling. It does not disclose how the parameters are used or whether any of them are optional, which is critical given the mismatch between the description and the parameter 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 extremely concise, which avoids verbosity, but it omits essential information about the parameters. It is not well-structured for an agent to understand the tool's contract.

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 sibling tools (e.g., 'timezone', 'iana-zones', 'validate-json'), the description is incomplete because it does not clarify how 'utc-time' differs or interact with them. The presence of unrelated parameters further exacerbates the incompleteness.

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 parameter descriptions are individually clear (e.g., 'URL to normalize or cite') but they have no apparent connection to the tool's stated purpose of returning a UTC timestamp. This leaves the agent unable to infer how to set these parameters correctly.

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 states the tool's purpose as returning the current UTC timestamp, but the associated parameters (url, host, json, zone) are unrelated to this purpose, creating confusion about what the tool actually does.

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?

No guidance is provided on when to use this tool or how it should be called. There is no mention of contexts where it is preferable over sibling tools like 'timezone' or 'iana-zones'.

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