Scryfall MCP Server

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

No annotations are provided, so the description carries the full burden. It mentions the tool 'Get[s] a random... card' with filters, but does not disclose behavioral traits such as rate limits, authentication needs, whether it returns a single card or multiple, error handling, or data sources (e.g., Scryfall). For a tool with no annotations, this leaves significant gaps in understanding its 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?

The description is a single, efficient sentence that is front-loaded with the core purpose ('Get a random Magic: The Gathering card') and adds necessary qualification ('optionally filtered by format or search criteria'). There is zero waste, and every word 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?

Given the complexity (7 parameters, no annotations, no output schema), the description is insufficient. It does not explain what the tool returns (e.g., card details, image, pricing), how randomness is implemented, or any limitations. For a tool with rich input options but no structured output or behavioral annotations, more context is needed to guide effective use.

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 all 7 parameters thoroughly. The description adds minimal value beyond the schema by mentioning 'filtered by format or search criteria', which loosely maps to 'format' and 'query' parameters but does not provide additional syntax or meaning. Baseline 3 is appropriate as the schema does the heavy lifting.

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 verb ('Get') and resource ('a random Magic: The Gathering card'), and specifies the optional filtering capabilities ('optionally filtered by format or search criteria'). It distinguishes itself from siblings like 'get_card' (likely for specific cards) and 'search_cards' (likely for broader searches) by focusing on random selection with filters.

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 for obtaining random cards with optional filters, but does not explicitly state when to use this tool versus alternatives like 'search_cards' or 'get_card'. It provides some context ('optionally filtered') but lacks explicit guidance on exclusions or comparisons with sibling tools.

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