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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds one genuinely useful behavioral fact beyond that: 'Checkout confirms current prices', warning that displayed prices may not be final. It says nothing about result size, pagination, or whether the catalog is static vs. live.

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 short sentences with the resource list front-loaded and the price caveat trailing, so nothing is buried. The density is good, though the phrase 'free immediate Belgian decks' is cryptic enough to cost a bit of clarity per word.

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 parameters, no output schema, and clear annotations, the description covers the basic shape of the response (decks, spreads, prices, languages, links). However, it omits the crucial relationship to the sibling listing tools and gives no indication of scope or volume, leaving an agent unsure when this tool is the right call.

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?

The tool takes zero parameters, so there is no parameter semantics to explain; the baseline for a parameterless tool applies. The description does not need to compensate for any schema gap.

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 verb 'Discover' plus an enumeration of resources (decks, spreads, prices, languages, entry points) gives a rough sense of a catalogue/browse tool, but the phrasing 'free immediate Belgian decks' is opaque and the description never clarifies how this differs from siblings like marselia_list_decks or marselia_get_deck. An agent can guess it is a catalog overview but cannot confidently distinguish it from the listing tools.

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 statement of when to use this catalogue versus marselia_list_decks, marselia_get_deck, or marselia_site_content, and no prerequisites or exclusions are given. The only implicit signal is the word 'Discover', which is not enough to route an agent among ten siblings.

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