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

With no annotations provided, the description carries the full burden of behavioral disclosure. It only states the output, but does not mention that many input parameters are ignored (as hinted by the schema's 'discarded' notes), whether it makes network calls, or its read-only nature. The schema itself suggests additional behaviors not reflected in the description.

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 single, efficient sentence with no unnecessary words. It is appropriately front-loaded and to the point, though it sacrifices detail for brevity.

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 nine optional parameters, no output schema, and no annotations. The one-sentence description is grossly insufficient to convey which parameters matter, what output format to expect, or how it interacts with the sibling tools. An agent would be unable to call this tool correctly based solely on the description.

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?

While the schema provides 100% description coverage for parameters, the tool description adds no parameter-specific meaning. It does not highlight that 'zone' is the primary parameter, and the presence of nine unrelated parameters (e.g., ref, url, city) without explanation in the description creates confusion about which ones are relevant to the timezone operation.

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 'Current time in a named IANA timezone' clearly states a specific action (get current time) and resource (named IANA timezone), distinguishing it from siblings like utc-time (no zone name) and iana-zones (list zones). It is concise and unambiguous.

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 no guidance on when to use this tool versus alternatives such as utc-time or tz-asia-manila. It does not mention exclusions or alternative selection criteria, leaving the agent to infer usage from the name alone.

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