Vinkius

Key Finder MCP. Instantly map every harmonic relationship between keys.

The Relative & Parallel Key Finder instantly maps out every structural relationship between musical keys. Give it any key, and it returns all its related partners—relative, parallel, homonymous, and those separated by a third-distance interval. It's an essential reference tool for composers needing instant analysis of Western music theory.

Key Finder MCP is compatible with Claude Claude
Key Finder MCP is compatible with ChatGPT ChatGPT
Key Finder MCP is compatible with Cursor Cursor
Key Finder MCP is compatible with Gemini Gemini
Key Finder MCP is compatible with Windsurf Windsurf
Key Finder MCP is compatible with VS Code VS Code
Key Finder MCP is compatible with JetBrains JetBrains
Key Finder MCP is compatible with Vercel Vercel
See Vinkius in Action

Give Claude and any AI agent real-world access

Map key relationships

It determines relative, parallel, antiparallel, homonymous, and third-distance partners for any given key.

Detail key signatures

It provides a technical breakdown of any key's signature, detailing accidental count, type (sharps/flats), and mode.

Reference modulation guides

It pulls up a complete reference table listing all known key signatures for planning modulations.

Waiting for input…

AI Agent
MCP Server

What AI agents can do with Relative & Parallel Key Finder (3 Tools)

Use these specific tools to analyze the complex structural rules of Western music, finding every relationship between keys with simple commands.

Make your AI actually useful.

Add this MCP to Claude, Cursor, or Windsurf and your AI stops guessing. It gets real tools to look things up, take action, and handle the stuff you keep doing by hand.

Start using Relative & Parallel Key Finder MCP

Find Key Relationships

Finds all structural partners for a key, including relative, parallel, antiparallel, homonymous, and third-distance keys.

Get Signature Details

Describes the technical composition of a given key by reporting its accidental...

Lookup Modulation Guide

Accesses a complete reference table detailing all known musical key signatures for...

Security and governance baked right in.

Pick your AI client below to get set up. Just create a Vinkius account, subscribe, and you're instantly up and running. We handle the entire backend infrastructure, delivering out-of-the-box support for HTTPS Streamable, SSE, and OAuth2—zero messy routing required.

Key Finder MCP is compatible with Claude

Claude AI

1

Open Claude Settings

Go to claude.ai, click your profile icon, then navigate to Customize → Connectors.

2

Add Custom Connector

Click the "+" button and select Add custom connector. Paste your Vinkius endpoint URL:

https://edge.vinkius.com/[YOUR_TOKEN_HERE]/mcp

Replace [YOUR_TOKEN_HERE] with your token from cloud.vinkius.com. For OAuth-protected servers, expand Advanced settings to add credentials.

3

Start a conversation

Open a new chat. The Key Finder integration is available immediately — no restart needed.

Choose How to Get Started

Build a custom MCP for your own tools, or connect a ready-made integration from our catalog.

Build Your Own

Turn any API into an MCP. Import a spec, define Agent Skills, or deploy with MCPFusion.

  • Import from OpenAPI, Swagger, or YAML specs
  • Create Agent Skills with progressive disclosure
  • Deploy to edge with MCPFusion framework
  • Built in DLP, auth, and compliance on each call
  • Real time usage dashboard and cost metering
  • Publish to catalog or keep private
Start building

Make Your AI Do More

Start with Relative & Parallel Key Finder, then connect any of our 5,200+ other servers whenever your AI needs more. One click, no limits.

  • Use this MCP plus 5,200+ others, all in one place
  • Add new capabilities to your AI anytime you want
  • Connections are secured and governed automatically
  • Track usage and costs across all your servers
  • Works with Claude, ChatGPT, Cursor, and more
  • New servers added to the catalog weekly

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The Challenge of Key Mapping

Writing music requires more than just knowing which chords sound good together. You have to manage the theory behind it. Today, figuring out what keys are structurally related means flipping through dense textbooks or constantly cross-referencing complex harmonic charts. This process is slow and highly prone to human error; you can easily miss a relative key or misread the signature count for a difficult modulation.

With this MCP, that manual work disappears. Your agent performs the entire structural analysis instantly. You input one key, and it spits out an exhaustive list of every related partner—relative, parallel, homonymous, and more. It’s not just fast; it's comprehensive.

Mastering Key Relationships with find_key_relationships

Before, determining all the possible keys related to your main key required multiple steps: first checking for parallels, then relative minors, and finally referencing specific interval rules. This meant juggling three or four different data sources just to get a full picture of available tones.

Now, one command does it all. The `find_key_relationships` tool gives you the whole structural map in a single output. You see every possible key option immediately, allowing you to compose with complete confidence.

What Key Finder MCP does for your AI

Writing music often means knowing the rules first. This MCP connects your AI agent to complex Western music theory logic. Need to know every possible key related to C Major, or figure out exactly how many flats a specific key signature needs? This utility handles all that structural mapping for you.

It's perfect for composers and students who need fast, reliable answers about harmonic relationships. Instead of flipping through thick textbooks or cross-referencing multiple charts, your AI client pulls the data directly. Vinkius hosts this MCP as part of a massive catalog, so once you connect your preferred agent, you gain instant access to all these musical tools.

You just ask for the relationship between keys, and it provides a complete map.

Built · Hosted · Managed by Vinkius Key Finder - Map Music Theory Relationships
Server ID 019f010f-ac86-736b-a943-cfe5bb0f5edd
Vinkius Inspector
Compliance Grade A+
Score 100/100
Vinkius Inspector Badge — Score 100/100

Frequently asked questions about Key Finder MCP

How do I use find_key_relationships to find all related keys? +

You simply ask your agent for the relationships of a specific key. For example: 'What are the find_key_relationships for C Major?'. The tool returns every structurally linked partner in one list.

Does get_signature_details only count sharps? +

No, it reports on both sharps and flats. You can ask it to check the signature details of any key, and it will give you the total accidental count, type (sharps/flats), and mode.

What is lookup_modulation_guide used for? +

It provides a full reference chart showing all known keys. This guide is crucial when planning large-scale modulations across an entire piece of music.

Can I use find_key_relationships to compare multiple keys? +

Yes, you can ask the agent to compare two or more keys using this tool. It will then list all the structural relationships that exist between them.

Is this useful for simple chord theory? +

This MCP focuses on deep harmonic structure and key relationships, not simple chords. Use it when you need to know why certain keys are related, not just what chords they contain.