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

The description discloses a critical behavior not in annotations: a $0.01 USDC payment requirement and a payTo address. It also notes the absence of API keys and specifies the return values. This adds substantial context beyond the readOnlyHint annotation.

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 short but poorly organized: it leads with the payment, then describes functionality, and ends with a long wallet address. Each sentence contains information, but the fragmented structure and raw address reduce readability.

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?

Without an output schema, the description does mention return values (now, UTC offset, DST), which is helpful. However, it omits error handling, input validation, and the exact payment flow, leaving the paid nature of the tool underspecified.

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?

The schema already fully documents the 'name' parameter with a description and default. The tool description merely repeats the default (America/Denver) and adds no new semantic information, so it provides no value 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 states the tool is an 'IANA timezone clock' that 'Returns now, UTC offset, DST', giving a specific verb and output. It is distinct from sibling tools like bizdays or check, though the payment note adds noise.

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 is provided on when to use this tool versus alternatives or any exclusions. The only usage hint is the default timezone, implying the parameter is optional, but no context is given for selecting this over other tools.

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