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

With no annotations, the description must disclose behavior, but it does not. It never states what executing the tool does, whether it returns a list, what side effects exist, or that many input parameters are discarded, despite the schema showing that several parameters are 'discarded after' checks.

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 front-loaded, but it is under-specified rather than concise. A single noun phrase does not earn its place because it fails to convey the tool's purpose or behavior.

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?

The tool has 9 optional parameters, no annotations, and no output schema, yet the description provides no information about return values, invocation behavior, or how it relates to the timezone/utc-time siblings. This is far too little context for an agent to select and call 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?

Schema description coverage is 100%, so each parameter is documented in the schema. The tool description adds no parameter-level meaning, but the schema already provides baseline clarity, so a 3 is appropriate.

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 fragment, 'Common IANA timezone names for clock calls,' rather than a statement of what the tool does. It identifies a resource and a loose context but lacks any verb or action, so an agent cannot tell whether this tool returns names, validates them, or does something else.

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 case involving timezone-related operations, but there is no explicit guidance on when to use this tool versus siblings like timezone or utc-time. No when/when-not conditions or alternatives are mentioned.

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