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

No annotations are provided, so the description carries the full burden. It discloses the output format (ISO 8601, UTC) and that it is a read operation. It does not mention error cases or caching, but for a stateless time-return tool this is sufficient and fully truthful.

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, front-loaded sentence with zero filler. It says exactly what the tool does and the output format without redundant 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?

Given there are no parameters, no output schema, and no annotations, the description fully captures everything an agent needs to invoke the tool correctly: the resource, the return format, and the timezone. Nothing is missing.

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?

There are zero parameters, and the schema coverage is 100% (vacuously). The description adds no parameter-specific detail because none is needed; the baseline for a no-parameter tool is 4, and nothing is missing.

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 specific verb ('Returns'), a clearly identified resource ('server time'), and the exact format (ISO 8601, UTC). This fully distinguishes it from the sibling tools 'add' and 'echo' with no ambiguity.

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 makes the tool's purpose self-evident, so an agent knows when to call it (whenever server time is needed). It does not explicitly name alternatives or exclusions, but no alternatives exist among the trivial siblings, so the context is clear enough.

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