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

Annotations already declare readOnly/openWorld=false/idempotent, so the safety profile is covered; the description adds real value by disclosing the per-card payload (name, dominant word, key symbol, plate and page URLs, decoy cards, review intervals) and a mandatory attribution requirement. That citation obligation is behavioral context not available in any structured field.

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?

Two sentences, front-loaded with the tool's identity and scope, with the return-shape and citation requirements following. Dense but every clause carries information; only the phrasing is slightly run-on.

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 no output schema, the description correctly spends its space enumerating the returned fields and the citation contract, which is what an agent needs. Minor gap: it doesn't explain what review intervals represent or how decoys should be used in a review, but nothing essential to invoking the tool is missing.

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 compensate. It does so for 'set' by naming every scope including 'all (78 cards)' and the four suits plus courts, and 'in the language asked' confirms that 'locale' controls output language. Exact enum strings still come from the schema, but the semantics are clear.

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 and resource (Marselia Academy review deck of the Tarot de Marseille) and enumerates the exact set scopes, so the agent knows precisely what it retrieves. It does not explicitly contrast itself with the closest sibling, marselia_get_deck, leaving overlap to inference.

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 mention of 'close cards a review uses as decoys, plus the review intervals' implies the tool serves spaced-repetition review, and the citation instruction tells the agent how to present output. However, there is no explicit when-to-use/when-not guidance versus marselia_get_deck, marselia_draw_card or marselia_get_card.

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