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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds useful non-schema context: the 10-credit Tier 1 cost and the Greer reduction formula, but it does not describe output format, permissions, or limits.

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 very compact and front-loads the computational formula before the group and cost metadata. There is no wasted text, though the abbreviated formula is terse enough to feel cryptic rather than fully explanatory.

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?

Because an output schema exists, return values need not be explained, and the annotations cover the safety profile. Still, the description leaves gaps around required date/year semantics and sibling routing, which are relevant for correct invocation in this large 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 50% (fields and precision are documented in the schema; date and year are not). The formula 'm+d+year reduced' adds some meaning for the required date and year inputs, implying month/day are taken from date and summed with year before reduction, but it never clarifies that date is a birth date or gives further usage detail.

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 the resource ('Year card') and the specific method ('per Greer (m+d+year reduced)'), so an agent can tell it computes a tarot year card. It does not explicitly differentiate from related siblings like astroway_tarot_marseille_year_card or astroway_tarot_rider_waite_birth_card, but the RWS-specific name and formula give a clear purpose.

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 when-to-use guidance, no exclusions, and no routing to alternatives. Sibling tools such as astroway_tarot_marseille_year_card and astroway_tarot_rider_waite_birth_card exist, but the description does not say when this one should be selected instead.

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