list_timezones

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

No annotations are provided, so the description must convey safety and behavior. It mentions read-only operations ('list or search') and filtering, but does not detail output format, potential limits, or other behavioral traits. This is acceptable for a simple list tool but leaves room for more transparency, hence a 3.

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 two sentences, each adding value: the first explains the core action and filter, the second clarifies the purpose. There is no redundancy or filler, making it highly concise and well-structured.

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 simple tool with one optional parameter and no output schema, the description covers the essential context: what it does, what the filter does, and why to use it (to get identifiers for other tools). It could optionally mention the return format, but it is sufficiently complete for the tool's simplicity, so a 4 is appropriate.

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 describes the 'query' parameter as a case-insensitive substring filter, but the tool description adds concrete meaning by specifying it can be a city, region, or country and providing examples ('kolkata', 'america'). This enriches parameter understanding beyond the schema, so it earns a 4.

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 clearly states the tool's function: to list or search valid IANA timezone identifiers. It uses a specific verb ('list or search') and identifies the resource, but it does not explicitly contrast with sibling tools like lookup_timezone, so it earns a 4 rather than 5.

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 provides clear usage context: use this tool to discover the exact identifier to pass to other tools. It implies when to use it but does not list exclusions or alternative tools explicitly, which keeps it at a 4.

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