Claude Code Multiplayer — Security skill for Claude Code

Claude Code Multiplayer

**One shared workspace your team and your agents both read and write through, where every file has an owner, every agent has a scope, and a gate neither of them controls refuses a false "done".**

The companion repository to the book *Claude Code Multiplayer*. More at [youcanbuildthings.com](https://youcanbuildthings.com).

In plain words: this is a folder of short shell scripts that sit between your coding agents and your files and refuse the edits that would step on each other. Two words show up everywhere below. A *gate* is a script that can say no. A *contract file* is the markdown table it reads to decide. You don't need either of them yet, and the branch you want is the first one under Start here.

[](https://github.com/regardo911/claude-code-multiplayer/actions/workflows/ci.yml)  

**These are coordination gates, not a security boundary, and `check-proof.sh` runs a command it read out of a markdown file.** [DISCLAIMER.md](DISCLAIMER.md)

Start here

**I have a repo I work in and I want the first gate running in it.**

bash install-workspace.sh /path/to/a/repo/you/work/in

It writes `workspace/`, fills the index with your git name and today's date, copies the scripts into `workspace/bin/`, and prints the hook block for you to paste. It doesn't touch your `.claude/settings.json`. It ends by printing the four lines that make the gate refuse and then make it stay quiet.

**I want to see the collision first.**

bash chapters/01-the-collision/setup.sh

Builds the two-agent repro from Chapter 1 and prints the two prompts to type.

**I finished the book and just want the files.**

Take the copy table below, or `cp -R workspace-template/ /your/re