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

With no annotations, the description carries the burden of behavioral disclosure. It states that it computes from IANA at runtime, ensures correctness for any future date, and reports live DST status. This gives clear expectations about dynamic behavior and scope. It does not mention output format, but for a read-only informational tool this is sufficient.

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?

Two well-structured sentences front-load the core purpose and zone breakdown, then add the runtime behavior note. No wasted words; all information is relevant and quickly scannable.

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 tool with one optional parameter and no output schema, the description covers the essential context: what zones are included, the default behavior (both), and the dynamic nature of the data. The only minor omission is an explicit statement of the return value structure, but the phrase 'live DST status' implies the output includes DST indicators, and the tool's simplicity makes this acceptable.

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 schema already documents the parameter 'zone' with a description covering values and default. The description adds valuable semantic detail by mapping 'Mainland' to Pacific/Auckland and 'Chatham Islands' to Pacific/Chatham, providing contextual meaning beyond the raw schema. This enhances the agent's ability to pick correct values.

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 specific verb and resource: it provides New Zealand time zones with live DST status, explicitly naming the two zones (Mainland and Chatham Islands) and their IANA identifiers. This clearly distinguishes it from sibling tools like au-timezone (Australia) and nz-public-holidays.

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 implies usage: it is for New Zealand time zone information and any future date. However, it does not explicitly state when to prefer this over au-timezone or other related tools, nor does it mention any exclusions or fallback logic. The guidance is adequate but not explicit.

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