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

With no annotations, the description must disclose behavior on its own, but it only states a noun phrase. It does not mention return values, side effects, ignored parameters, or any post-call behavior, despite several parameter descriptions referencing values being 'discarded.'

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 single sentence is concise, but it is under-specified rather than tightly structured. It provides no action, no key qualifier beyond 'common,' and no front-loaded operational detail.

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?

A 9-parameter tool with no output schema and no annotations needs a much richer description. The description leaves the return type, accepted input semantics, and relationship to the parameters completely unspecified.

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 its own description and the baseline is 3. The tool description adds no parameter-level meaning, but the schema's parameter descriptions are present and moderately informative, even though they seem unrelated to IANA timezone names.

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?

Names a concrete resource ('Common IANA timezone names') and the intended domain ('clock calls'), so an agent can infer the tool returns a timezone list. However, it lacks a verb/action such as retrieves or lists, and does not distinguish itself from 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?

No guidance on when to call this tool versus timezone, utc-time, or other siblings. The only hint is 'for clock calls,' which implies context but provides no exclusions or alternative routing.

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