MusclesWorked

io.github.csjoblomPublished by GitHub account csjoblomv0.1.0Updated Oct 28, 2026

Exercise-to-muscle mapping: 856 exercises, 65 muscles, workout analysis & alternatives.

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Overview

AI-generated overview

Local MCP server that connects an assistant to the MusclesWorked exercise-to-muscle API for muscle activation data, exercise lookup and workout analysis.

What you can do
  • Look up primary, secondary and stabilizer muscles for a given exercise
  • Find exercises that target a specific muscle, with optional filters
  • Analyze a workout for muscle coverage, gaps and imbalances
  • Find alternative exercises ranked by muscle overlap
  • Search exercises and muscles by name to discover their IDs
When to use it
Useful when you want an assistant to answer training questions about which muscles an exercise works, to build or check a workout for coverage and imbalances, or to suggest substitute exercises. It fits fitness planning and coaching conversations rather than general development work.
Requirements
Runs locally via npx (Node.js) as a stdio process, desktop MCP clients only. Needs a MusclesWorked API key, supplied through the MUSCLESWORKED_API_KEY environment variable or the --api-key argument; keys are obtained from the provider's dashboard. Network access to the MusclesWorked API is required, and the base URL can be overridden with MUSCLESWORKED_API_URL.
Before you install
The API key is a secret: it is passed in plain text in client configuration and command-line arguments, so keep it out of shared config files and repositories. Requests, including the exercises and workouts you describe, are sent to the third-party MusclesWorked service. The tools are read-only lookups and analysis; no data is written or deleted.

Installation

In SourceWeft

  1. Open MusclesWorked in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Desktop only via STDIO. STDIO servers start a local process, so they need the SourceWeft desktop host.

Other MCP clients

Follow the launch instructions in the repository.

README

musclesworked-mcp

MCP server for the musclesworked.com exercise-to-muscle mapping API.

Connects Claude Desktop, Claude Code, Cursor, and other MCP clients to 856 exercises and 65 muscles with detailed primary/secondary/stabilizer activation data across 14 muscle groups.

Setup

Get an API key at musclesworked.com/dashboard.

Claude Desktop

Add to your claude_desktop_config.json:

json
{  "mcpServers": {    "musclesworked": {      "command": "npx",      "args": ["-y", "musclesworked-mcp"],      "env": {        "MUSCLESWORKED_API_KEY": "mw_live_..."      }    }  }}

Claude Code

bash
claude mcp add musclesworked -- npx -y musclesworked-mcp --api-key mw_live_...

Or add to .mcp.json:

json
{  "mcpServers": {    "musclesworked": {      "command": "npx",      "args": ["-y", "musclesworked-mcp", "--api-key", "mw_live_..."]    }  }}

Cursor

Add to .cursor/mcp.json:

json
{  "mcpServers": {    "musclesworked": {      "command": "npx",      "args": ["-y", "musclesworked-mcp"],      "env": {        "MUSCLESWORKED_API_KEY": "mw_live_..."      }    }  }}

Tools

ToolDescription
get_muscles_workedGet primary, secondary, and stabilizer muscles for an exercise
find_exercisesFind exercises targeting a specific muscle with optional filters
analyze_workoutAnalyze a workout for coverage, gaps, and imbalances
get_alternativesFind alternative exercises ranked by muscle overlap
search_exercisesSearch exercises by name to discover IDs
search_musclesSearch muscles by name to discover IDs

Example Prompts

  • "What muscles does the barbell bench press work?"
  • "Find bodyweight exercises for my chest"
  • "Analyze my push day: bench press, overhead press, tricep pushdown, lateral raise"
  • "What are some alternatives to barbell squats?"
  • "Search for exercises that target the hamstrings"

Configuration

OptionDescription
--api-key <key>API key (or set MUSCLESWORKED_API_KEY env var)
MUSCLESWORKED_API_URLOverride base URL (default: https://musclesworked.com)

Development

bash
git clone https://github.com/csjoblom/musclesworked-mcp.gitcd musclesworked-mcpnpm installnpm run build
# Test with MCP InspectorMUSCLESWORKED_API_KEY=mw_live_... npx @modelcontextprotocol/inspector node dist/index.js

License

MIT

Source: README.md at commit 9f4422f

Tools

0
SourceWeft has not started this package in its sandbox yet, so its tools are not known.

Version history

1
  1. v0.1.0LatestSep 16, 2026

Score

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