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

With no annotations and no output schema, the description carries the full burden for behavioral transparency, but it discloses no behavior at all: no side effects, return format, error cases, or operational characteristics. The tool could return a list, check membership, or perform some other action.

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 and free of fluff, but it is too terse to be well-structured. It front-loads the name but omits the essential verb and parameter guidance, so brevity comes at the cost of 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?

Given the tool's ambiguous name, nine optional parameters, and lack of output schema, the description is far too incomplete. It does not explain what inputs are relevant, what the tool returns, what 'common' means, or how it relates to clock calls.

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?

Although the schema has 100% property description coverage, the tool description never connects any parameter to the tool's purpose. The 'zone' parameter is plausibly relevant, but the schema also includes eight unrelated optional parameters with 'discarded' notes, making it unclear which input iana-zones actually consumes.

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 names a resource ('common IANA timezone names') and a context ('clock calls'), but uses no verb, so it is unclear whether the tool returns, validates, or lists these names. It is not a tautology, but it does not clearly state the action.

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' gives a weak usage context, suggesting it is relevant when dealing with timezone names for clock-related tools. However, it does not explain when to prefer this over sibling tools like timezone or utc-time, nor does it provide any exclusions.

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