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

Annotations are empty, so the description carries the full disclosure burden. It discloses the monetary cost ($0.001 USDC), the output formats, and timezone/default behavior. The main non-obvious behavior—cost—is explicitly stated.

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. The primary purpose and output formats are front-loaded, and the cost note is appended clearly at the end.

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?

For a tool with one optional parameter and no output schema, the description provides the necessary invocation context: formats, default timezone, and cost. A minor gap is the absence of an example response, but the named formats sufficiently convey the expected output.

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%, and the schema already documents that timezone is an optional IANA timezone name defaulting to UTC. The description merely repeats 'optional timezone' without adding new parameter semantics, so the baseline 3 applies.

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 precise action and resource: 'Get the current time in multiple formats' and lists the specific formats (ISO 8601, Unix seconds, Unix milliseconds). This clearly distinguishes it from unrelated siblings like health, text.structure, and uuid.

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 usage context is clear: it returns the current time, optionally in a specified timezone, defaulting to UTC. It does not explicitly name when not to use it, but the sibling tools are unrelated, so no alternative routing is necessary.

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