Riot Games

Account By Puuid

account_by_puuid

Read-onlyIdempotent

Look up a Riot account (game_name, tag_line, puuid) by puuid via the regional Riot Account API (americas | europe | asia).

Input Schema

Name	Required	Description	Default
`puuid`	Yes
`region`	Yes

Output Schema

Name	Required	Description
`puuid`	No	Player UUID
`tagLine`	No	Riot tag line
`gameName`	No	Riot game name

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedMay 27, 2026

addedInput schema / examples

Added value: +[
+  {
+    "puuid": "player-puuid-123456",
+    "region": "americas"
+  }
+]

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "properties": {
+    "gameName": {
+      "description": "Riot game name",
+      "type": "string"
+    },
+    "puuid": {
+      "description": "Player UUID",
+      "type": "string"
+    },
+    "tagLine": {
+      "description": "Riot tag line",
+      "type": "string"
+    }
+  },
+  "type": "object"
+}

First observedMay 20, 2026

TDQS

A3.8/5.0

Behavior3/5

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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, destructiveHint=false; description adds regional API detail but no additional behavioral traits like rate limits or error handling.

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

Conciseness4/5

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

Single sentence, front-loaded with essential info, but could be more structured (e.g., separating purpose and parameters).

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

Completeness4/5

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

Given simple tool with output schema and annotations, description covers purpose, key fields, and regional limitation; no missing critical information for typical use.

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?

Schema coverage 0% with no parameter descriptions; description mentions 'by puuid' and lists regions but does not detail parameter formats or constraints (e.g., puuid string format), partially compensating.

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

Purpose5/5

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

Clearly states 'Look up a Riot account' with specific fields (game_name, tag_line, puuid) and distinguishes from sibling account_by_riot_id by specifying lookup key (puuid) and regional API.

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

Usage Guidelines4/5

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

Specifies regional scope (americas, europe, asia) and key (puuid), implying alternative account_by_riot_id for riot_id lookups, but lacks explicit when-not guidance.

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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