card_named

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

With no annotations provided, the description carries the burden of behavioral disclosure. It states the miss behavior (error with Scryfall's details) and suggests using card_fuzzy as fallback, which is helpful. However, it doesn't describe edge cases like case-insensitivity (which is in schema), network behavior, or whether the tool handles partial matches. It also doesn't mention that legalities field exists but not detailed.

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 concise and front-loaded: it starts with the main purpose, then describes return on hit, miss behavior, and usage guidance. Each sentence adds value without redundancy. It's tightly written and easy to scan.

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 lookup tool with simple parameters (2, 1 required) and no output schema, the description is fairly complete. It covers the main use case, the error case, and suggests an alternative. However, it could be more complete by mentioning that the returned object includes many fields (which it does mention), so a 4 is justified. The lack of annotations is compensated reasonably well.

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 coverage is 100%, so the schema already documents both parameters. The description adds a bit of context (exact-name lookup implies the name parameter's role) but doesn't provide additional semantics beyond the schema, such as how set interacts with name or any formatting requirements. Baseline 3 is appropriate given the high schema coverage.

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 states the tool does an exact-name lookup of a Magic card, identifies the resource (Scryfall card object) and differentiates from the sibling card_fuzzy. It explicitly mentions the behavior on hit (returns full card object) and on miss (error with details), which is specific and distinguishes it from other lookup 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?

The description explicitly says to use when the caller has the exact card name, and mentions card_fuzzy as an alternative for when exact name is not available. However, it does not describe other siblings like card_search or card_collection, so the guidance is somewhat limited but clear.

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