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

With no annotations provided, the description must carry the burden of behavioral disclosure. It only states that the tool returns the current time, giving no detail about expected input validation, output format, network dependency, or error behavior. The description also does not address the notable mismatch between its mention of an IANA timezone and the schema, which lacks such a parameter.

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 short sentence that is front-loaded and easy to read. It wastes no words, but its brevity omits essential usage and parameter details, so it is concise yet incomplete.

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 no annotations, no output schema, and a schema with nine unrelated optional parameters, the description is far from sufficient. It does not explain how to provide the required IANA timezone, what the response looks like, or the role of the other parameters. The tool cannot be reliably selected or invoked based on this description alone.

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?

Although schema description coverage is 100%, the schema contains no parameter for an IANA timezone, making the description's promise impossible to fulfill based on the provided input fields. The description does not clarify how to specify the timezone nor why the nine listed parameters such as 'ref' and 'query' are relevant. This is a critical semantic gap that prevents correct invocation.

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 the tool's function and distinguishes it from sibling tools like utc-time and iana-zones. However, it uses a noun phrase rather than an explicit verb and does not name its sibling alternatives. Overall the purpose is specific and understandable.

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 gives no guidance on when to use this tool versus alternatives such as utc-time or iana-zones. It neither states the conditions for selection nor excludes cases where another tool would be better. The 'named IANA timezone' phrasing implies a usage context, but no explicit guidance is provided.

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