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

Without any annotations, the description must carry the behavioral disclosure. It states only that the tool returns current time in a named timezone but says nothing about invalid zone handling, return format, timezone edge cases (DST), or the meaning of the other eight schema parameters. The presence of many unrelated parameters without explanation leaves ambiguous 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?

A seven-word sentence states the core function with zero redundancy. The opening words 'Current time' instantly convey the result, and the rest specifies the scope. This is an appropriately sized description for a simple read-only tool.

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 tool is simple but the schema contains nine parameters, and the description does not clearly indicate that 'zone' is the only relevant parameter. There is no output schema, but the description's 'Current time' partially conveys the return. It lacks completeness by not clarifying the role of the other params or return format, but it is adequate for a minimal tool.

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 baseline is 3 even though the description adds no parameter-level detail. The schema already documents 'zone' as an IANA timezone name and marks the other parameters as discarded; the description provides no extra guidance on which parameter to supply or how the others interact with the tool.

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?

Description names a concrete verb and resource ('Current time in a named IANA timezone') and distinguishes the tool from siblings such as utc-time (UTC only) and iana-zones (zone list). The single-sentence statement fully conveys the tool's purpose.

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?

No guidance on when to choose this over alternatives like utc-time or iana-zones, nor any mention of restrictions or preferred contexts. The description implies use for a specific timezone but does not explain boundary cases or alternative tools.

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