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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint=false and destructiveHint=false, so the safety profile is covered. The description adds genuinely useful operational context the annotations cannot: the POST endpoint, the required input set, and a 10-credit Tier 1 cost. It does not explain what a Greer year card represents or how the computation resolves, leaving some behavioral gaps.

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 one-line definition plus a compact bracketed metadata block is tightly front-loaded, with endpoint, requirements and cost immediately visible. No filler sentences. Slightly terse on substance but structurally efficient.

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, and the cost/endpoint/required metadata round out the call mechanics. However, for a specialized esoteric calculation keyed to a named method, the description gives no indication of what the caller should expect or how it differs meaningfully from the birth-card sibling.

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 60%, and the schema itself documents art, fields, and precision in reasonable detail. The description only restates the two required parameters (date, year), which are already visible in the schema's required array, so it adds little semantic value. Baseline 3 for a moderately documented schema is appropriate.

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 artifact (Year card) computed per a named method (Greer) within a specific deck tradition (Marseille). It is clearly separable from the Rider-Waite sibling astroway_tarot_rider_waite_year_card by the tradition named. It stops short of explicitly distinguishing itself from its sibling, so not a 5.

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 or when-not-to-use guidance and no alternative tool is named. The agent must infer from the title alone that this is the Marseille-specific variant of a year-card calculation.

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