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

With no annotations, the description carries the behavioral burden. It states the core read-only lookup behavior, and 'current time' implies no mutation, but it does not mention output format, handling of invalid timezone names, or whether this is a network call. The behavior is simple, but some detail is missing.

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 one short, front-loaded sentence with no filler. Every word earns its place, and it is easy to scan.

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 definition is adequate for a simple tool, but with no output schema and several seemingly unrelated parameters in the input schema, the description does not clarify what the return value looks like or confirm that 'zone' is the operative parameter. The schema helps, but the description leaves some context to inference.

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 parameter meanings are already documented, especially the 'zone' parameter described as 'IANA timezone name.' The description reinforces the IANA concept but does not add syntax, format, or usage details beyond the schema.

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 identifies the resource and result: current time for an IANA timezone. It is easy to distinguish from related tools like utc-time or iana-zones, though it lacks an explicit verb such as 'returns' and does not explicitly name sibling alternatives.

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 like utc-time or iana-zones. The intended use is only implied by the phrase 'current time in a named IANA timezone,' with no exclusions, prerequisites, or alternative routing.

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