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

With no annotations, the description must carry the behavioral burden. It only states the tool provides 'names for clock calls,' with no disclosure of whether the tool returns a list, validates input, performs a read-only lookup, or has side effects. The actual behavior is left entirely to inference.

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 extremely short and contains no filler, but it is under-specified relative to the tool's eight parameters and unclear purpose. It is concise but not appropriately proportioned to the tool's apparent complexity, preventing a higher score.

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?

There is no output schema and the description does not explain what the tool does with the diverse parameter set or what form the timezone names take. An agent would struggle to know how to call this tool correctly or interpret its results, so the description is materially incomplete.

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?

The input schema provides descriptions for every parameter, so the baseline is 3 even though the description adds no parameter-level meaning. The description does not connect the listed parameters (ref, url, city, etc.) to timezone names, leaving an unexplained gap, but the schema itself covers the mechanics.

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 identifies the resource as 'Common IANA timezone names for clock calls,' which conveys the subject matter but lacks a verb or explicit action (e.g., returns, lists, validates). It also doesn't distinguish this tool from sibling tools like 'timezone' or 'utc-time' that also relate to timezones.

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 hint about when the tool might be used, but there is no explicit guidance on when to choose this tool over alternatives, when not to use it, or any prerequisites. The description offers no exclusion or comparison to sibling tools.

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