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

With no annotations, the description must carry the full burden of behavioral disclosure. It only says 'current time' without indicating return format, error handling for invalid zones, whether it makes network calls, or if it's read-only. For a simple tool this is a minimal but insufficient disclosure.

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 short sentence, front-loaded with the core purpose. It is concise and to the point, though it might benefit from a few more words to cover essential behavior. No fluff or redundancy.

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 is simple but lacks an output schema. The description does not explain the return format, error behavior, or the fact that only 'zone' is used. The unrelated parameters in the schema are a significant gap that could mislead an agent. Given the potential for misuse, more context is needed.

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 has a description. However, the description does not clarify that only 'zone' is relevant; the schema includes url, host, and json with descriptions unrelated to timezone, creating confusion. The description adds no meaning beyond the schema and fails to resolve the mismatch.

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 states a clear, specific purpose: getting the current time in a named IANA timezone. It distinguishes from siblings like utc-time (which likely returns UTC) and iana-zones (which lists zones). The verb 'get' is implied, and the resource is 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 provided on when to use this tool versus alternatives like utc-time or iana-zones. There is no mention of prerequisites, fallback, or exclusions. An agent has no help in choosing this over similar siblings.

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