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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered. The description adds genuinely useful context beyond that: the 50-year range limit, the credit cost (10 credits, Tier 1), and the endpoint. It stops short of describing failure behavior for out-of-range requests, so not a 5.

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?

Front-loads the purpose sentence, then uses a compact bracketed metadata block for group, endpoint, required fields, and cost. No wasted prose. Slightly fragmentary but every element earns 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?

With an output schema present, return values need no explanation, and annotations cover the safety profile. The description supplies purpose, cost, range constraint, and required inputs, leaving only year-input semantics unstated. Complete enough for correct invocation of a simple two-parameter range calculator.

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 50%: fields and precision are documented in the schema, while startYear/endYear carry no field-level description. The description names them as required and ties them to the 50-year range cap, but adds no format or boundary semantics (accepted year range, BC handling, ordering). Adequate but does not fully compensate for the coverage gap.

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?

States a specific verb ("Calculate") and resource ("Rave New Year dates"), then pins the concept precisely as "the exact moment Sun enters Gate 41". That definition clearly distinguishes it from sibling design-date and transit tools without needing to name them.

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 "Max range: 50 years" constraint gives a usable boundary, but there is no explicit when-to-use or when-not-to-use guidance relative to siblings like astroway_hd_design_date or astroway_hd_dream_rave. Usage is only implied by the distinctive purpose statement.

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