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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the safety profile is covered; the description still adds value by disclosing sort order ('oldest first') and the shape of each record (family, dates, maker, place, free scan count, localized URLs), which matters because there is no output schema. It does not say whether the list is exhaustive or paginated.

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?

A single front-loaded sentence with the purpose and ordering stated before the field list. The long parenthetical of deck names is somewhat heavy but earns its place as disambiguating scope.

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?

For a read-only, zero-required-parameter listing tool with full annotation coverage and no output schema, the description supplies ordering and per-record fields, which is close to what an agent needs. The only real gap is the locale behavior and whether results are truncated.

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?

There is one parameter (locale) with 0% schema description coverage, so the description must carry it. 'Localized page URLs' hints that locale changes the returned URLs, but it does not say whether deck names/descriptions are also translated or what happens with an unsupported locale (the enum list is only in the schema).

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 ('List') and a specific resource ('the historical and modern tarot decks of the Marselia encyclopedia'), plus ordering (oldest first) and returned fields. The parenthetical deck families make it unmistakably distinct from marselia_get_deck (single deck) and marselia_list_cards (cards within a deck).

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?

Usage is only implied: an agent can infer this is the browse-all-decks entry point, but the description never says when to prefer it over marselia_get_deck, marselia_search_* or marselia_catalog, nor any exclusions. No prerequisites or alternatives are named.

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