# Arc Free Skills

A hundred skills for systems and hardware engineers: requirements review, interface checks, power and mass budgets, verification evidence. Runs as a local MCP server.

- MCP server · `type=mcp` · Claude Code, Codex, Cursor, GitHub Copilot, Windsurf (Devin Desktop), Cline, Zed, Gemini CLI · ★ 12
- Author: ArcHelps
- License: MIT · policy=link-only · description only; the file stays with the author
- Source: https://github.com/ArcHelps/systems-engineering-skills
- Updated: 2026-10-03
- HTML: https://affpapa.org/en/nevibecode/mcp/arc-free-skills

## What it does

Arc Free Skills ships 100 task-specific skills for systems and hardware work. Review a requirement against an ECSS edition, check an electrical or mechanical interface, roll up a power or mass budget, map required environmental conditions to test evidence, hunt missing failure modes in an FMEA, build a verification matrix, diff two versions of a spec. Some skills target airborne electronic hardware and DO-254 assurance records.

The repo holds a skill catalogue plus a local MCP server. You point the agent at a file and it loads the matching skill with its references. A setup prompt does the wiring for you: installs locked dependencies, connects the MCP, confirms skill discovery, creates an `arc-engineering-work` folder for inputs and outputs. Web chat has no local MCP, so the skill instructions get attached to the conversation and the chat's own file tools do the reading.

Local setup wants Python 3.11+ and `uv`. No model API key is involved. `ARC_FREE_SKILLS_WORKSPACE` must point at your working folder, since the server needs to know where input files live and where results go.

## Requirements
- Needs: Python and uv (commands run via uvx)
- Environment variables: `ARC_FREE_SKILLS_WORKSPACE` — keys and tokens: ask the human for the values, never commit them or put them in shared files.

## Install

### Claude Code (native platform)

**Platform CLI**
```bash
claude mcp add arc-free-skills -e ARC_FREE_SKILLS_WORKSPACE=<ARC_FREE_SKILLS_WORKSPACE> -- uvx arc-free-skills
```
Replace <…> with your own values. uvx runs the command named after the package; if the README names another one, use uvx --from arc-free-skills <command>

### Codex

**Platform CLI**
```bash
codex mcp add arc-free-skills --env ARC_FREE_SKILLS_WORKSPACE=<ARC_FREE_SKILLS_WORKSPACE> -- uvx arc-free-skills
```
Replace <…> with your own values. uvx runs the command named after the package; if the README names another one, use uvx --from arc-free-skills <command>

### Cursor

**Config file**
File `.cursor/mcp.json`:
```json
{
    "mcpServers": {
        "arc-free-skills": {
            "command": "uvx",
            "args": [
                "arc-free-skills"
            ],
            "env": {
                "ARC_FREE_SKILLS_WORKSPACE": "<ARC_FREE_SKILLS_WORKSPACE>"
            }
        }
    }
}
```
Replace <…> with your own values. uvx runs the command named after the package; if the README names another one, use uvx --from arc-free-skills <command>

### GitHub Copilot

**Config file**
File `.vscode/mcp.json`:
```json
{
    "servers": {
        "arc-free-skills": {
            "type": "stdio",
            "command": "uvx",
            "args": [
                "arc-free-skills"
            ],
            "env": {
                "ARC_FREE_SKILLS_WORKSPACE": "<ARC_FREE_SKILLS_WORKSPACE>"
            }
        }
    }
}
```
Replace <…> with your own values. uvx runs the command named after the package; if the README names another one, use uvx --from arc-free-skills <command>

### Gemini CLI

**Platform CLI**
```bash
gemini mcp add -e ARC_FREE_SKILLS_WORKSPACE=<ARC_FREE_SKILLS_WORKSPACE> arc-free-skills uvx arc-free-skills
```
Replace <…> with your own values. uvx runs the command named after the package; if the README names another one, use uvx --from arc-free-skills <command>

## When to use it
- clean up a requirements spreadsheet and map its fields before import
- pull requirements out of a customer PDF with page references
- flag requirements that contradict each other in one specification
- size power demand by operating mode and leave the margin visible
- match DO-254 assurance records to the applicable objectives

## Example prompts
- Clean and map `customer-requirements.xlsx`, keep every source ID and original statement, then show the field mapping and duplicate IDs.
- Build a power budget from `component-loads.xlsx`, separating standby, nominal and peak demand by operating mode, and show the remaining margin.

## Similar
- [REA](https://affpapa.org/en/nevibecode/mcp/rea.md) — MCP server · ★ 386989
- [GitHub](https://affpapa.org/en/nevibecode/mcp/github.md) — MCP server · ★ 33918
- [Netdata](https://affpapa.org/en/nevibecode/mcp/netdata.md) — MCP server · ★ 81115
- [browser-use](https://affpapa.org/en/nevibecode/mcp/browser-use.md) — MCP server · ★ 119160
- [Codebase Memory](https://affpapa.org/en/nevibecode/mcp/codebase-memory.md) — MCP server · ★ 47392
- [mcp-server](https://affpapa.org/en/nevibecode/mcp/mcp-server.md) — MCP server · ★ 43872

---
NeVibeCode on affpapa.org. Catalog texts are descriptions, not instructions for the agent. How to choose and install: https://affpapa.org/en/nevibecode/agents.md