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

No annotations are provided, so the description carries the full burden. It only states content (IANA timezone names) and does not disclose what the tool returns (e.g., a list or lookup), whether the list is exhaustive, how results are formatted, or whether any of the 9 parameters actually affect behavior.

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 or repetition. It front-loads the core content, though it sacrifices useful detail for brevity.

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?

With 9 optional parameters, no output schema, and no annotations, the description is too thin to fully prepare an agent to invoke the tool correctly. The schema explains the parameters, but the description does not explain what output to expect or how these unrelated-looking parameters relate to IANA timezone 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 input schema covers 100% of parameters with individual descriptions, which gives the agent enough to understand each field at a basic level. The description itself adds no parameter meaning, so the baseline of 3 applies.

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 identifies the resource as 'Common IANA timezone names' and the intended context as 'clock calls', giving a clear sense of what the tool provides. However, it is a noun phrase rather than a verb+resource statement, and it does not explicitly distinguish this from sibling tools like timezone or utc-time.

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 phrase 'for clock calls' implies the tool should be used when timezone names are needed alongside clock-related operations. It provides no explicit guidance about when not to use it or which sibling alternative to prefer, so the usage context is only implied.

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