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

No annotations are provided, and the description gives no details about side effects, error handling, or output format. It only states the core function without any behavioral context (e.g., whether it is read-only, what happens with invalid zones, or whether it makes network calls).

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, succinct sentence with no redundant words. It is well-structured for a simple tool, conveying the essential purpose without elaboration.

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 description lacks any context about the output (e.g., time format, timezone offset, error behavior) or how to handle invalid zones. The presence of many seemingly irrelevant parameters in the schema further confuses the context, making the tool's complete behavior unclear.

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 the schema has descriptions for all 9 parameters, the tool description adds no clarification about which parameter is relevant. The schema itself is confusing, with many parameters marked as 'discarded after the shape check' that are unrelated to the timezone function. The description does not help the agent understand the role of each parameter, especially 'zone'.

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's function: 'Current time in a named IANA timezone.' It identifies a specific action (get current time) and a specific resource (named IANA timezone), making its purpose unambiguous and distinct from other time-related tools.

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 like utc-time or iana-zones. It does not mention any conditions, use cases, or exclusions, leaving the agent to infer when this tool is appropriate.

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