missing_from_set

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

With no annotations, the description carries the burden of explaining behavior. It discloses the core computation ('hasn't completed a playset (4)') and output shape ('needed count per card'), but it does not mention ordering, inclusion of zero-count cards, or behavior when the set is fully completed. These gaps leave some behavioral context unspecified.

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 concise sentences convey purpose, output, and filtering capability. The description is front-loaded and every word adds value—no filler or redundancy.

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 simple filtered-query tool with an output schema (which covers return details), the description is mostly sufficient: it communicates the main operation, the output count, and the optional filter. It lacks explicit usage guidance and parameter format details, but given the low complexity, the coverage is good.

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 adds meaning to 'rarity' by calling it an 'Optional rarity filter', but it does not explain the format or allowed values for rarity, nor does it explicitly connect 'set_code' to the set identifier beyond the schema's property name. Partial compensation 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 clearly identifies what the tool does: 'Cards in a set the player hasn't completed a playset (4) of' names the resource (set) and the specific filtering logic. It also states the output ('Returns a 'needed' count per card'), which distinguishes it from siblings like deck_gap (deck-focused) and search_cards (general card search).

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 description implies usage context—finding cards needed to complete playsets in a given set—but does not explicitly state when to use this tool versus alternatives, nor does it provide exclusions or alternate tool recommendations. It is functional but lacks direct guidance.

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