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

The description provides no behavioral details beyond the action itself. It does not disclose that only the 'zone' parameter matters, that other parameters are ignored, or that the operation is read-only and side-effect free. With no annotations, the description carries the full burden, and it fails to clarify the tool's actual behavior given the misleading schema.

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, focused sentence that directly states the tool's purpose. It is concise and front-loaded with the core action, containing no filler.

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 tool with nine parameters and no output schema, the description is grossly incomplete. It fails to clarify the role of the eight non-zone parameters, does not describe the return format or any side effects, and leaves the agent guessing about which parameters are actually used. This is a severe gap for effective tool selection and invocation.

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 already documents each parameter with descriptions, achieving 100% coverage, so the baseline is 3. The description adds no extra semantic meaning about the parameters; it only implies that 'zone' is the relevant one. It does not explain why the other parameters exist or that they are discarded.

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 states a clear purpose: returning the current time for a named IANA timezone. It identifies the resource (timezone) and the action (get current time), and it distinguishes from siblings like 'utc-time' and 'iana-zones'. However, the input schema contains many unrelated parameters (e.g., 'url', 'ref', 'city'), which are not mentioned and could confuse an agent about the tool's actual scope.

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' or 'iana-zones'. The description gives no context about use cases, prerequisites, or exclusions, leaving the agent to infer entirely.

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