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

With no annotations at all, the description carries the full burden of disclosing behavior. It reveals nothing about side effects, return values, or access requirements. It does not even clearly say whether the tool only returns common names or can be called with a zone parameter for validation.

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 terse, a single sentence, but this is under-specification rather than concise efficiency. It front-loads nothing useful and lacks structural signposts for an agent.

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 9-parameter tool with no annotations and no output schema, this one-line description is wholly insufficient. It doesn't explain what the tool returns, what the intended use is, or how to properly choose parameters.

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 baseline is 3. The description adds no extra meaning beyond the schema, and its single-timezone hint doesn't explain how the 9 parameters connect to IANA zones. Still, because the schema names and describes every parameter, a 3 is warranted.

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 'Common IANA timezone names for clock calls' loosely restates the tool name ('iana-zones') and lacks an action verb. It doesn't clarify whether the tool lists names, validates a zone, or returns a constant. No comparison to sibling tools like 'timezone' or 'utc-time' helps an agent distinguish it.

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 gives no indication of when to use this tool versus the sibling 'timezone' or 'utc-time'. It provides no exclusions, prerequisites, or alternative routing, so an agent cannot decide between them.

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