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

With no annotations provided, the description carries the full burden of disclosure. It discloses that results are 'approximate' and that it uses 'MVP solar math', which is important behavioral context. However, it does not mention potential limitations such as timezone handling, edge cases, or the exact output format, leaving some gaps.

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 concise sentence that front-loads the main action ('Compute') and resource ('sunrise/sunset/golden-hour windows'). It includes valuable qualifiers ('approximate', 'no API key', 'MVP solar math') without any redundant wording, making every word earn its place.

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 the absence of an output schema, the description should explain return values, but it only implies outputs through the phrase 'sunrise/sunset/golden-hour windows'. It does not mention timezone or time format, which is relevant for astronomical times. The inclusion of 'approximate' and 'MVP' gives some context, but overall the description is not fully complete for a complex calculation 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% with all three parameters described (lat, lon, date). The description adds no additional meaning beyond what the schema already provides, simply restating 'for lat/lon/date'. Thus, a baseline score of 3 is appropriate.

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 computes approximate sunrise, sunset, and golden-hour windows for lat/lon/date using specific verbs and a specific resource. It distinguishes itself from sibling tools by focusing on solar calculations, which none of the siblings address. The 'MVP solar math' note further clarifies the scope.

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 provides clear context for usage by mentioning 'no API key', indicating this is a self-contained alternative to API-based services. It also qualifies the tool as 'MVP solar math', suggesting it is for approximate estimates. However, it does not explicitly name alternatives or state when not to use the tool, so it falls short of a 5.

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