MTG Deckbuilder MCP

price_decklist

Calculates per-card USD prices and total cost for a Magic decklist, sorted most expensive first.

Instructions

Quick price check of a decklist: per-card USD price and total, most expensive first.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "decklist": "<decklist>"
    },
    "name": "price_decklist"
  }
}

Input Schema

Name	Required	Description	Default
`decklist`	Yes

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Sep 28, 2026

TDQS

B3.1/5.0

Behavior3/5

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

No annotations are provided, so the description carries the full behavioral burden. It discloses output ordering and USD pricing, but does not explicitly state read-only safety, authentication needs, rate limits, or error behavior. 'Price check' implies read-only, but that is inferential rather than stated.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

A single front-loaded sentence with no filler. Every phrase adds useful scope or output context.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The tool is simple and an output schema exists, so return values do not need full explanation in the description. However, the required decklist format is left unspecified and no usage alternatives are given, leaving an agent to guess for the one required input.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters2/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The required 'decklist' parameter has 0% schema description coverage. The description only says 'of a decklist' and does not define the expected format (e.g., plain text, Arena, MTGO), so it does not compensate for the missing schema documentation.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('price check of a decklist') and adds scope details: per-card USD price, total, and ordering. Clear what the tool does, but it does not distinguish itself from siblings such as analyze_deck or search_cards.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description names no explicit when-to-use, when-not-to-use, or alternative tools. 'Quick price check' implies a use case, but it does not help an agent choose this over analyze_deck or get_card.

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

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