MapleStory MCP Server

get_union_info

Retrieve union information for a MapleStory character including level, grade, and artifact details by providing the character name and optional date.

Instructions

Retrieve union information for a MapleStory character including level, grade, and artifact details

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": {
      "characterName": "<characterName>"
    },
    "name": "get_union_info"
  }
}

Input Schema

Name	Required	Description	Default
`characterName`	Yes	The name of the character to look up union info for
`date`	No	Date for union info in YYYY-MM-DD format (optional, defaults to yesterday)

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.2Mar 14, 2026

TDQS

C2.9/5.0

Behavior2/5

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 mentions what data is retrieved but omits critical details such as rate limits, authentication requirements, error handling, or data freshness (e.g., if it fetches live or cached data). This is inadequate for a tool with potential external dependencies.

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?

The description is a single, efficient sentence that front-loads the core purpose without unnecessary words. Every part earns its place by specifying the action, target, and key data points, making it easy to scan and understand quickly.

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

Completeness2/5

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

Given no annotations and no output schema, the description is incomplete for a tool that likely interacts with an external game API. It lacks details on return format (e.g., structure of union info), error cases, or behavioral constraints, which are essential for reliable agent use in this context.

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

Parameters3/5

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

Schema description coverage is 100%, so the input schema fully documents both parameters (characterName and date). The description adds no additional parameter semantics beyond implying union info retrieval, aligning with the baseline score when schema handles the heavy lifting.

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?

The description clearly states the action ('retrieve') and resource ('union information for a MapleStory character'), specifying the included details (level, grade, artifact details). It distinguishes from siblings like get_character_basic_info or get_union_raider by focusing on union-specific data, though it doesn't explicitly contrast them.

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?

No guidance is provided on when to use this tool versus alternatives like get_character_full_info or get_union_raider. The description implies usage for union-related data but lacks explicit context, prerequisites, or exclusions, leaving the agent to infer based on tool names alone.

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

Deploy Server