Biorhythm Compatibility

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and closed-world, so the safety profile is covered. The description does add genuine value beyond that: the exact scoring formula, the fact that the offset is fixed at birth so the result never changes, and an explicit disclaimer that the model has no evidential support. It does not cover any auth or rate-limit behavior, but none is implied here.

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 prose is front-loaded with the core meaning and then the formula, followed by compact bracketed metadata for group, endpoint, required params and cost. The formula is dense but earns its place by pre-empting 'what does the number mean' questions; nothing is redundant.

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 not be explained, yet the description explains the score's construction anyway. Cost, endpoint and required fields are listed. The only gap is the absence of sibling routing guidance, which matters given the very crowded compatibility toolset.

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 0%, so the description must carry the load, and it partially does: 'the offset is set at birth' clarifies that the two dates are birth dates and that only dates (not times or places) matter. It does not state the date format, nor which parameter is person A versus B, both of which the schema pattern only partially supplies.

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 states a specific computation: per-cycle phase offset between two people across the 23/28/33-day cycles plus the resulting percentage and mean. This clearly distinguishes a two-person compatibility tool from the single-person sibling astroway_wellness_biorhythm, though it never names that sibling explicitly.

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?

There is no explicit when-to-use or when-not-to-use guidance, and no named alternative among the many compatibility tools (Vedic, Chinese zodiac, human design, etc.). The only hint is the phrase 'two people', which implies this is the pair variant, leaving routing to inference from the name.

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