Add one or more Magic: The Gathering cards to your inventory. Specify card ID, quantity, and foil finish to batch-add items to your collection.
Add one or more cards to the authenticated user's inventory. Accepts a batch - pass a single-item array for one card. This is a real write. Use update_inventory to change quantities, remove_inventory to delete a row. Requires IWMM_API_KEY.
| Name | Required | Description | Default |
|---|---|---|---|
| items | Yes |
Changes observed during successful MCP inspections.
v0.6.2Input schema / $schemaAdded value: +"http://json-schema.org/draft-07/schema#"v0.0.1Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Declares 'real write' to indicate mutation, but lacks details on side effects, idempotency, or rate limits. With empty annotations, more context would help.
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 succinct sentences: purpose, batch usage note, alternatives and auth. No filler.
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?
Covers all essential information for a write tool with clear schema. Missing return value description, but not critical for basic usage.
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 already provides descriptions for all parameters. Description adds minor clarity (e.g., single-item array for one card) but doesn't significantly extend understanding.
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?
Clear verb (add) and resource (cards to inventory). Distinguishes from siblings by explicitly naming update_inventory and remove_inventory.
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 states when to use this tool (adding cards) vs alternatives (update_inventory, remove_inventory). Also specifies authentication requirement (IWMM_API_KEY).
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.