PlayByKey Music Theory runs on your own machine — the client starts it, so there is no endpoint to ping. 390 installs a week from npm. Last commit 15 Sep 2026.
Chords, scales, progressions, transposition, and MIDI tools for music theory AI agents.
Today is the operative word: we check PlayByKey Music Theory every 15 minutes and re-read its code on every release. Watch it and you find out the day that stops being true.
This server runs on your own machine — install it with the package manager and the client starts it for you. Package name taken from the official registry entry.
claude mcp add theory-mcp -- npx -y @playbykey/theory-mcp
{
"mcpServers": {
"theory-mcp": {
"args": [
"-y",
"@playbykey/theory-mcp"
],
"command": "npx"
}
}
}
[mcp_servers.theory-mcp]
command = "npx"
args = ["-y", "@playbykey/theory-mcp"]
{
"mcpServers": {
"theory-mcp": {
"args": [
"-y",
"@playbykey/theory-mcp"
],
"command": "npx"
}
}
}
{
"mcpServers": {
"theory-mcp": {
"args": [
"-y",
"@playbykey/theory-mcp"
],
"command": "npx"
}
}
}
Scales, chords, progressions, key detection, and genre intelligence for your AI. No API keys needed.
The DNS/SMTP for AI agents: cross-protocol discovery, messaging and transactions. No middleman fees.
PostgreSQL, MySQL, and SQL Server in one session. 26 read-only MCP tools for AI agents.
Cross-platform music and game resolution for AI agents across 15+ platforms.
Identity, authorization, audit trails, and revocable permissions for AI agents accessing MCP tools.
Zero-false-positive tripwires for AI agents — decoy tools + canary tokens catch prompt injection.
x402-paid Upload and Flight Search tools for AI agents.
The project tracker for teams of humans and AI agents — in plain files. MCP server + CLI.
Answers built from our own checks of this server.