Lunar Calendar MCP Server

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

With no annotations provided, the description carries the full burden of behavioral disclosure. While it describes what the tool outputs (calendar with phases, illumination, events), it lacks critical behavioral details such as whether calculations are location-sensitive (implied but not explicit), data freshness, error handling, or format of the visual output. For a tool with computational aspects, this is a significant gap.

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 appropriately sized (four sentences) and front-loaded with the core functionality. Each sentence adds value: first defines the tool, second details outputs, third provides usage context, fourth clarifies data formats. There's minimal redundancy, though the final sentence could be integrated more tightly with the first.

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 tool's moderate complexity (computational, multiple outputs), no annotations, and no output schema, the description is adequate but incomplete. It covers purpose and usage well but lacks behavioral transparency about calculations, error cases, or output structure. For a tool that likely returns structured data, more detail on the return format would be helpful.

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%, so the schema already documents all three parameters (month, year, location) with their types and constraints. The description doesn't add any parameter-specific semantics beyond what's in the schema, such as explaining how location affects calculations or valid year ranges. Baseline 3 is appropriate when the schema does the heavy lifting.

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's purpose with specific verbs ('creates', 'shows', 'displays', 'highlights', 'provides') and resources ('monthly calendar', 'moon phases', 'daily moon phase names', 'illumination percentages', 'lunar events'). It distinguishes from siblings like 'get_moon_phase' (single phase) and 'predict_moon_phases' (future predictions) by emphasizing comprehensive monthly coverage with both visual and numerical data.

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 when to use this tool ('Perfect for gardening, fishing, photography planning, or any activities influenced by lunar cycles'), which helps differentiate it from siblings focused on compatibility, fortune, or festivals. However, it doesn't explicitly state when NOT to use it or name specific alternatives like 'get_moon_phase' for single-day data.

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