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

With no annotations, the description conveys that this is a read-only time lookup, which is the core behavioral trait. It does not disclose return format, error behavior, or how the zone parameter relates to the many other parameters that are described as discarded, so some behavioral context is left to the 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 sentence with no wasted words, and the key constraint 'named IANA timezone' is front-loaded. Every word contributes to understanding the tool's purpose.

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 minimally adequate for a simple time lookup, but with no output schema and nine optional parameters, it leaves out the return format and the relationship between the zone parameter and the other discarded parameters. A bit more operational detail would make it complete.

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?

Schema description coverage is 100%, so the schema already documents all nine parameters, including 'IANA timezone name' for zone. The description adds little beyond reinforcing that the timezone must be a named IANA zone and does not clarify which parameter is primary.

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 that the tool returns the current time for a named IANA timezone, clearly identifying both the resource and the operation. It is distinguishable from the sibling utc-time through the 'named IANA timezone' qualifier, though it does not explicitly contrast itself with siblings.

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 intended use is implied: call this when you need the current time for a specific IANA timezone. However, no alternatives, exclusions, or when-not-to-use conditions are provided, even though relevant siblings like utc-time, iana-zones, and geo-hint exist.

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