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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It only says what the data is, not what the tool does with inputs, whether anything is discarded, what the response looks like, or how 'common' is determined. The schema reveals that several parameters are discarded after checks, but the description itself does not convey this.

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 has no filler, but it is under-specified rather than efficiently complete. A single clause may be concise, but it does not provide enough structure or detail to support correct tool selection and invocation.

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 nine optional parameters, no output schema, and no annotations, this description is inadequate. It does not explain why diverse parameters are accepted, what 'common' means, what the caller receives, or how this tool fits with timezone-related siblings. The lack of context makes the tool genuinely confusing.

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 each parameter has an individual description; therefore baseline is 3 even without parameter details in the tool description. However, the description adds no meaning about how these parameters relate to IANA timezone names, and the parameter set (ref, url, city, feed, host, json, path) appears disconnected from the stated purpose.

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.' It identifies the resource at a basic level and adds the qualifier 'common', but it lacks a verb such as 'list' or 'return', and it is close to restating the tool name. It also does not distinguish itself from timezone-related siblings like `timezone` or `utc-time`.

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 use context, but there is no explicit when-to-use guidance, no exclusions, and no comparison to sibling tools. An agent would have to infer when this tool is preferred over `timezone` or `utc-time`.

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