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

With no annotations and a minimal description, the tool's behavior is entirely opaque. It does not disclose whether it is read-only, what it returns, or any side effects. The description mentions 'discarded after the call' for some parameters, implying side effects or transformations, but this is unexplained and inconsistent.

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 succinct, consisting of a single sentence, which is appropriately brief for a simple tool. However, it is so terse that it lacks necessary detail. The structure is straightforward, but the brevity compromises usefulness.

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 apparent simplicity, the description is grossly incomplete. It fails to explain the tool's return value, the purpose of the unrelated parameters, or how it fits among sibling timezone tools. The mismatched parameter descriptions raise more questions than they answer, leaving the agent without enough context to use the tool correctly.

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 schema includes nine optional parameters, but their descriptions are largely irrelevant to a timezone-name tool. For example, 'ref' is described as 'Git ref name; discarded after the shape check' and 'city' as 'City name for a public weather hint; discarded after the call'. Only 'zone' aligns with the tool's purpose, but even that is ambiguous. The descriptions confuse rather than clarify, providing no meaningful semantics for the agent.

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' suggests it provides a list of timezone names, but it does not explicitly state that it returns a list or how it relates to the input schema. It also fails to distinguish itself from sibling tools like 'timezone' and 'tz-africa-dakar', leaving the agent guessing about its exact function.

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?

No usage instructions are provided. The description does not indicate when this tool should be invoked over alternatives, nor does it explain how to use the parameters. The agent is left without any guidance on selecting or calling this tool.

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