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

With no annotations present, the description carries the full burden of behavioral disclosure. It only says "Current time in a named IANA timezone," giving no information about output format, validation behavior, network access, or side effects. The schema's parameter notes like "discarded" and "no side effects" do not cover the tool's overall behavior.

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 extremely concise and front-loaded, with no filler words. Every word contributes to stating the tool's core function.

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 is far too incomplete for a tool with seven parameters and no output schema. It fails to identify the required timezone input, explain what the tool returns, or reconcile the obvious mismatch between the description and the input schema. An agent cannot confidently call this tool correctly.

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 all seven parameters have individual schema descriptions, none of them represents a timezone name. The description does not map "named IANA timezone" to any parameter, so an agent cannot determine which field to populate. The schema coverage is high but irrelevant to the tool's stated purpose, and the description adds no parameter-level guidance.

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 also distinguishes itself from siblings like utc-time and iana-zones by emphasizing "named IANA timezone." However, it lacks an explicit verb and the purpose is undermined by the input schema showing no timezone parameter.

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 about when to use this tool versus alternatives such as utc-time or iana-zones. The phrase "named IANA timezone" implies a use case, but no conditions, exclusions, or alternative routing are provided.

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