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. It only says 'current time' which implies a read, but it does not disclose any side effects, authentication requirements, rate limits, or output format. The presence of nine parameters with 'discarded' notes in the schema is not reflected in the description, so behavioral context is minimal.

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 with no filler. It is front-loaded with the core purpose, which is efficient. However, its brevity borders on under-specification, though it is appropriately sized for the minimal stated purpose.

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, none required, and no output schema. The description does not explain how to invoke it (which parameter to use) or what the response looks like. It also does not address why unrelated parameters exist in the schema, leaving significant gaps for an agent trying to use it correctly.

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%, but the tool description adds no meaning beyond what the schema already states. Moreover, the schema includes many unrelated parameters (ref, url, city, etc.) with descriptions like 'discarded', and the description does not clarify that only the 'zone' parameter is relevant for this tool. This ambiguity hinders correct parameter selection.

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 states the action (providing current time) and the resource (a named IANA timezone). It implicitly distinguishes from sibling tools like utc-time (likely gives UTC) and iana-zones (likely lists zones), though it does not explicitly name alternatives.

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 provides no guidance on when to use this tool versus alternatives such as utc-time or iana-zones. There is no mention of context, prerequisites, or exclusion conditions, leaving the agent to infer usage.

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