Western Moon Phase

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

Annotations already declare readOnly, idempotent, and non-destructive hints, and the description adds behavioral context beyond those: it specifies the computation engine, clarifies that this is the tropical system rather than Vedic, and enumerates the exact returned values. The docs link additionally references the output and error contract, although the description itself could have said a little more about error handling.

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 front-loaded with a concise summary, then organized into labeled sections for workflow, input contract, sibling differentiation, and full documentation. Every section serves a distinct purpose with no filler or redundant restatement.

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 annotations, output schema, input schema, and sibling list, the description is complete: it covers what the tool returns, how to call it, what to call instead, what to call next, and where to find the full contract. Nothing an agent needs to invoke this safely is missing.

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 coverage is already 100%, and the description adds a concrete example value ('2026-05-01') and reinforces that the date is optional and defaults to today. The response_format parameter is not echoed in the prose, but the schema describes it fully with an enum and default.

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 opens with a specific verb ('Calculates'), a clear resource ('tropical lunar phase'), a date scope ('for any date'), and the return fields. It also explicitly distinguishes itself from its closest siblings in the 'DO NOT CONFUSE WITH' section, so an agent can identify this tool without ambiguity.

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?

It states standalone usage ('BEFORE: None — standalone'), suggests the natural next step for full-month data, and explicitly warns against confusing this tool with the calendar and Vedic panchanga tools. This gives clear when-to-use and when-not-to-use guidance.

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