Coin Flip MCP Server
コインフリップMCPサーバー
random.orgの乱数APIを用いて、真にランダムなコイン投げを提供するMCPサーバーです。このサーバーは、設定可能なサイドを持つランダムな結果を生成するツールを提供することで、モデルコンテキストプロトコル(MCP)のデモンストレーションを行います。
特徴
ツール
flip_coin- 設定可能な面数でコインを投げるオプションの
sidesパラメータ(デフォルト: 2)random.org の真のランダム性を使用
エッジケース(0、1、または負の側)の特別な処理
2面の場合:「表」または「裏」を返します
3面の場合:「表」、「裏」、または「_」を返します
n>3 面の場合: 「X 面に着地しました」を返します。
Related MCP server: MCP Lottery Demo
発達
依存関係をインストールします:
npm installサーバーを構築します。
npm run build自動リビルドを使用した開発の場合:
npm run watchインストール
Claude Desktop で使用するには、サーバー設定を追加します。
MacOSの場合: ~/Library/Application Support/Claude/claude_desktop_config.json
Windows の場合: %APPDATA%/Claude/claude_desktop_config.json
{
"mcpServers": {
"coin-flip": {
"command": "npx",
"args": ["-y", "@modelcontextprotocol/server-coin-flip"]
}
}
}使用例
Claude DesktopなどのMCPクライアントに接続すると、自然言語を使ってコイントスツールを操作できるようになります。例えば:
「コインを投げる」
「6面サイコロを振る」
「1から20までのランダムな数字をください」
サーバーは random.org からの真のランダム性を使用して結果を生成します。
デバッグ
MCPサーバーはstdio経由で通信するため、デバッグが困難になる場合があります。MCP Inspectorの使用をお勧めします。
npx @modelcontextprotocol/inspector node build/index.js貢献
貢献を歓迎します!お気軽にプルリクエストを送信してください。
ライセンス
マサチューセッツ工科大学
Available Tools
1 toolflip_coinB
Flip a coin with n sides using true randomness from random.org. For 3-sided coins, try creative side names like:
past/present/future (temporal analysis)
true/unknown/false (epistemic states)
win/draw/lose (outcome evaluation)
rock/paper/scissors (cyclic relationships)
less/same/more (abstraction levels)
below/within/above (hierarchical positioning)
predecessor/current/successor (ordinal progression)
Meta-usage patterns:
Use less/same/more to guide abstraction level of discourse
Use past/present/future to determine temporal focus
Chain multiple flips to create decision trees
Use predecessor/current/successor for ordinal analysis
Ordinal Meta-patterns:
Use predecessor to refine previous concepts
Use current to stabilize existing patterns
Use successor to evolve into new forms
Default ternary values are -/0/+
| Name | Required | Description | Default |
|---|---|---|---|
| sideNames | No | Optional custom names for sides (must match number of sides) | |
| sides | No | Number of sides (default: 3) |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden. It discloses the randomness source ('true randomness from random.org') and default behavior ('Default ternary values are -/0/+'), but it doesn't cover potential rate limits, error conditions, or output format details. This provides some behavioral context but leaves gaps.
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 overly verbose and poorly structured, with extensive examples and meta-patterns that may not all be necessary. It's front-loaded with the core purpose but then diverges into lengthy lists and patterns, reducing clarity and efficiency. Some content could be trimmed without losing essential information.
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 tool's low complexity (2 parameters, no output schema, no annotations), the description is somewhat complete but excessive. It covers purpose and usage ideas but lacks output details and could be more focused. The richness in examples compensates partially but doesn't fully align with the tool's simplicity.
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?
The schema description coverage is 100%, so the baseline is 3. The description adds value by explaining creative uses for 3-sided coins and meta-patterns, which indirectly clarifies parameter semantics (e.g., how 'sideNames' might be applied). However, it doesn't explicitly detail parameter meanings beyond what the schema provides.
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 tool's purpose: 'Flip a coin with n sides using true randomness from random.org.' This specifies the verb ('Flip'), resource ('coin'), and randomness source. However, it doesn't distinguish from siblings since there are none, so it can't achieve a perfect 5.
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 provides implied usage through examples of 3-sided coins and meta-usage patterns, suggesting when to use specific configurations. However, it lacks explicit guidance on when to use this tool versus alternatives (none exist) or clear exclusions, keeping it at an intermediate level.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Tool Schema Changelog
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
1 tool update
v1.0.0- First observed
flip_coin
TDQS
Scored across 1 tool
With only one tool, there is no possibility of confusion or overlap between tools. The tool 'flip_coin' has a single, clearly defined purpose.
Since there is only one tool, naming consistency is inherently perfect. The tool name 'flip_coin' follows a clear verb_noun pattern.
A single tool is too few for a server's purpose, as it limits functionality and suggests an incomplete or overly narrow scope. While the tool is versatile, the server would benefit from additional tools to support more complex operations.
The server's domain appears to be random generation or decision-making, but with only one tool, there are significant gaps. For example, there are no tools for setting parameters, retrieving results, or managing multiple flips in a structured way, which limits agent workflows.
Maintenance
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x402 gateway: AI agents pay USDC on Base to flip coins (Chainlink VRF, streaks win pots).
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