swu_lookup_card

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

With no annotations, the description carries the burden of behavioral disclosure. It states it is a read operation and returns a CardDetail record, but does not disclose error/not-found behavior or the fact that prefix matching is allowed (schema provides that). Adequate but not rich.

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?

The description is a single, well-structured sentence that front-loads the verb and key criteria. No redundant or filler content.

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 lookup tool with a full output schema and complete parameter descriptions, the description covers the essential purpose and return type. It lacks only error/not-found behavior and explicit alternative tool guidance, which are minor for this complexity.

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 describes all three parameters at 100% coverage, including the OR constraint. The tool description restates this constraint without adding additional meaning or format details, so it does not exceed the schema's contribution.

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 uses the specific verb 'Look up' and identifies the resource as a specific Star Wars Unlimited card, distinguished by query criteria (name or set_code+card_number). This clearly differentiates it from sibling tools like swu_search_cards or swu_random_card.

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 when you have an exact or prefix card name or a set+number combination, but it does not explicitly contrast with swu_search_cards for broad searches or mention when not to use it. Sibling context exists, but the description itself offers no exclusion or alternative guidance.

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