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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered structurally. The description adds only the 'Greer method' label and says nothing about determinism, required inputs' semantics, or what the computed card represents. With the annotation bar lowered, this still contributes almost no behavioral context.

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 text is short and front-loaded with no filler sentences, but it is under-specified rather than genuinely concise. Two of the three lines are bracketed metadata tags that consume space without informing invocation.

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?

An output schema exists, so return values need not be described. But for a tool with two required, undocumented parameters sitting among many near-duplicate siblings, the description omits what a year card is, when to prefer it over the Rider-Waite variant or the birth card, and what date/year should represent. It is not complete enough for reliable selection.

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 only 50%: 'date' and 'year' have no descriptions at all, and the description supplies no compensating meaning (e.g., whose birth date, or why both a date and a year are required). It does not explain how the two required parameters combine to produce a year card. The 'fields'/'precision' parameters are documented in-schema only.

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 names a specific resource and methodology ('Year card per Greer method'), which adds a differentiating detail beyond the title. However, it is a bare noun phrase with no verb, and it does nothing to distinguish this from near-identical siblings such as astroway_tarot_rider_waite_year_card or astroway_tarot_marseille_birth_card. An agent must infer that this is the Marseille-deck computation.

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 prerequisites, and no mention of alternatives. The bracketed group and cost tags are billing metadata, not usage guidance. Given the enormous sibling set with several overlapping 'year card' and 'birth card' variants, the absence of routing guidance is a real gap.

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