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

With no annotations, the description carries the full burden, but it only states the output and says nothing about input validation, error behavior, or the fact that most schema parameters are discarded. The schema's 'discarded' notes hint at behavior the description itself does not disclose.

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 a concise, front-loaded phrase with no redundant words. It is slightly under-specified for the complex schema, but as a concise statement of purpose it earns a strong 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?

Given the nine-parameter schema, absent annotations, and no output schema, the description does not provide enough context for an agent to know exactly which parameter to set or what response to expect. The schema partially compensates, but the description itself is 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 has 100% description coverage for its parameters, so the baseline is 3. The tool description adds no extra parameter meaning beyond what the schema already provides, such as specifying that 'zone' is the key input.

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 returns the current time for a named IANA timezone, which is a specific resource and result. It is conceptually distinct from sibling tools like utc-time and iana-zones, though it does not explicitly name them.

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?

There is no guidance on when to use this tool versus alternatives such as utc-time, nor any hint that only the 'zone' parameter is relevant. The description alone does not help an agent choose among the many optional schema parameters.

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