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

With no annotations provided, the description carries the full burden of disclosing behavior. It states what is returned but does not mention side effects (or lack thereof), error handling for invalid zone names, or that it is a read-only operation.

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 that is front-loaded with the core purpose. No wasted words or redundant detail.

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?

Despite the tool's apparent simplicity, the schema contains three irrelevant parameters that the description does not address. A complete description would clarify that url, host, and json are unused, and would note error behavior for invalid IANA zone names.

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 schema lists four parameters (url, host, json, zone) but only 'zone' is relevant to this tool; the other three appear to be copy-paste artifacts from sibling tools. The description adds no clarification about which parameters are actually used and which are ignored.

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 time in a named IANA timezone' clearly identifies the tool's function—returning the current time for a specified timezone—and distinguishes it from sibling tools like utc-time (UTC time) and iana-zones (zone listing). The verb is implicit but unambiguous.

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 given on when to use this tool versus closely related siblings such as utc-time or iana-zones. The description does not state conditions under which this tool is preferred or alternatives to consider.

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