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

The annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds useful behavior context: it accepts both printing ids and gameplay card ids, and it lists the exact fields returned. It does not mention pagination or locale effects, but these are minor for a read-only listing operation.

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?

Three sentences with no filler: purpose and output fields are front-loaded, then the dual-id behavior is stated, then the routing guidance to get_card is provided. Every sentence earns its place.

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?

The description lists the return fields and id formats, which is enough to call the tool correctly for typical reprint/alt-art questions. Since there is no output schema, describing the fields is helpful. A small gap is that it does not explicitly state pagination or what happens when no printings match, but the read-only nature and clear purpose keep this from being a serious omission.

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 schema already provides 100% parameter description coverage for both id and locale, including the same id format examples ('A1-001', 'PK_000010'). The description does not add meaning beyond the schema for either parameter, so the baseline of 3 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 verb and resource: 'List every printing of one card across all sets,' with concrete output fields. It also distinguishes itself from get_card, which is a sibling tool, by noting the get_card only returns the first printing.

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?

Explicitly tells the agent when to use this tool: when the question is about reprints, alt arts, or pull sources. It also names the alternative (get_card) and explains why that alternative is insufficient in this case.

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