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

With no annotations, the description carries the full burden of behavioral disclosure. It only states the basic function and offers no details on error handling (e.g., invalid zone), DST considerations, return format, or whether the time is server-side or client-side. The description is a bare statement.

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, consisting of a single, clear sentence. It wastes no words. However, it may be too terse, leaving out necessary context about parameters.

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 simple tool, the description is incomplete. It lacks information about return format, error behavior, and, critically, the fact that only the 'zone' parameter is used while others are irrelevant. The misleading schema adds complexity that the description fails to address.

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?

While the schema has 100% coverage (each parameter has a description), the description does not clarify that only 'zone' is actually used. The presence of 'url', 'host', and 'json' with unrelated descriptions (normalize, cite, validate) is confusing; an agent might wonder if the tool handles those as well. The description should explicitly state that only 'zone' is relevant, but it does not.

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 function: returning current time for a named IANA timezone. It implicitly differentiates from siblings like utc-time (which likely returns UTC) and iana-zones (which likely lists zones). However, it does not explicitly mention the 'zone' parameter or clarify that other schema fields are irrelevant, which slightly muddies the purpose.

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?

There is no guidance on when to use this tool versus alternatives like utc-time or iana-zones. No context is given for when a named timezone lookup is preferred over UTC or zone enumeration.

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