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

With no annotations, the description carries full burden. It only states the action and resource but does not disclose whether it returns a formatted string, whether it validates the zone, or if any side effects exist (e.g., network calls). The description adds no behavioral context beyond the literal purpose.

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?

One concise sentence that front-loads the core purpose. No wasted words, though it is so brief that it sacrifices useful 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?

The tool has nine parameters, only one of which (zone) is relevant, and no output schema. The description does not clarify that the other parameters are irrelevant or ignored, nor does it specify the return format. For a simple tool this is borderline, but the presence of many extraneous parameters makes the lack of clarification a notable gap.

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 coverage is 100%, so each parameter is documented individually. The description adds the clarification 'named' (implying a name like 'America/New_York' rather than an offset), but it does not explicitly point to the 'zone' parameter among the nine. This is a marginal addition over the schema.

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?

States a specific action ('Current time') and resource ('named IANA timezone'), clearly distinguishing it from siblings like utc-time (which likely returns UTC) and iana-zones (which lists zones). The wording is unambiguous but lacks detail on the output format.

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?

Provides no guidance on when to use this tool versus alternatives such as utc-time or iana-zones. The description implies it is for a specific zone but does not explicitly state exclusions or contexts, leaving the agent to infer from the name alone.

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