card_rulings

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It transparently describes the return format (list with data array containing published_at, comment, source), the meaning of empty data (no rulings), and the internal resolution step for names. This is thorough for a read-only lookup tool.

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 two sentences: the first states the purpose and distinguishes it from oracle text, the second explains input options and return structure. It is front-loaded with the core purpose, contains no filler, and every clause 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?

For a simple lookup tool with two optional parameters, no output schema, and no annotations, the description fully covers what an agent needs: input resolution, output format, and the edge case of no rulings. It is complete and self-sufficient.

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 100%, so the schema already documents both parameters clearly. The description adds minor redundancy by repeating the exact-name and skip-hop details, but does not provide additional semantic meaning beyond the schema. Baseline 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?

The description clearly states the tool returns official Wizards/Scryfall rulings for a single card, distinguishing it from oracle text. It names the resource (rulings), the verb (get/fetch implied), and specifies input requirements (exact name or card id). This differentiates it from sibling tools like card_named or card_search which serve different purposes.

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 explains how to invoke it: provide an exact name (which resolves via an exact lookup first) or a card id to skip that hop. This implies the correct usage context but does not explicitly mention when not to use it or name alternatives like card_named for fuzzy searches. Still, the usage context is clear enough for an agent to decide correctly.

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