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

There are no annotations, so the description must carry the behavioral disclosure burden. It does not say whether the tool returns a list, performs a lookup, mutates anything, or ignores parameters. The description provides no behavioral traits beyond the tool name itself.

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 short, but it is under-specified rather than concise. A six-word noun phrase is not appropriately sized for a tool with nine diverse parameters and no output schema; it does not earn its place by providing usable operational content.

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?

Given nine optional parameters, no annotations, and no output schema, this description is far from complete. It does not explain what the agent should expect as a result, how the parameters relate to IANA timezone names, or what 'clock calls' means in this context.

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 the schema's parameter descriptions carry the semantic weight. The tool description adds no parameter-level meaning, but the baseline of 3 applies because there is no gap in schema documentation to compensate for.

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 is a noun phrase 'Common IANA timezone names for clock calls' rather than a statement of what the tool does. It largely restates the tool name ('IANA timezone names' ≈ 'iana-zones') and adds only a vague reference to 'clock calls' without specifying an operation such as returning, listing, or validating.

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' hints at a context, but it does not explicitly say when to use this tool versus siblings like 'timezone' or 'utc-time'. No alternatives or exclusions are mentioned, so an agent receives almost no routing guidance.

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