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

The description is minimal and does not disclose behavioral traits such as read-only nature, failure modes, or output format. With empty annotations, the description carries full burden but provides only output content and timezone.

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 very concise at one sentence, front-loading the output items and scope. It earns its place but could usefully mention the date default and output structure.

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 low complexity (2 simple params, no output schema), the description is incomplete. It omits output format (e.g., time strings) and the default behavior of the date parameter. The agent lacks sufficient details to handle the response correctly.

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 description adds context that island parameter filters geographically and output is in HST, but does not explain the date parameter (defaults to today). Schema already describes date format and island enum, so description adds marginal value beyond 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 returns sunrise, sunset, and daylight duration by island, which aligns with the tool name. However, it does not explicitly differentiate from sibling tools like get_moon_phase or get_weather, though the distinct content makes the purpose clear.

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 explicit guidance on when to use this tool versus alternatives. The description lacks any 'when to use' or 'when not to use' instructions, and no alternatives are mentioned.

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