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

No annotations are provided, so the description alone must disclose behavior. It is only a noun phrase and gives no indication of side effects, read-only nature, returned values, or what happens with the many parameters.

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 with no filler words. However, it is overly terse and repeats the topic already implied by the name, so the economy is under-specification rather than effective clarity.

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 parameters, no output schema, and no annotations, a single uninformative sentence is far too sparse. The intended workflow, what the tool returns, which parameters are used, and what 'clock calls' actually means are all missing.

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 description coverage is 100%, so the parameters are individually documented. The tool description itself adds no parameter-level meaning, but the baseline of 3 is appropriate because the schema is already doing the heavy lifting.

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 essentially restates the tool name: 'iana-zones' becomes 'IANA timezone names', adding only the vague context 'for clock calls'. It never states the operation the tool performs, such as listing, validating, or returning zones.

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 some relationship to clock/time usage, but it gives no concrete condition for when to invoke this tool. It also does not compare against strong siblings like 'timezone' or 'utc-time', leaving the choice entirely to inference.

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