AgentSync

A fast, portable CLI tool for synchronizing AI agent configurations across multiple AI coding assistants using symbolic links.

Why AgentSync?

Different AI coding tools expect configuration files in various locations:

AgentSync maintains a single source of truth in .agents/ and creates symlinks to all required locations.

Features

• 🔗 Symlinks over copies - Changes propagate instantly
• 📝 TOML configuration - Human-readable, easy to maintain
• 📋 Gitignore management - Automatically updates .gitignore
• 🖥️ Cross-platform - Linux, macOS, Windows
• 🚀 CI-friendly - Gracefully skips when binary unavailable
• ⚡ Fast - Single static binary, no runtime dependencies

Installation

From GitHub Releases (Recommended)

Download the latest release for your platform:

# macOS (Apple Silicon)
curl -LO https://github.com/dallay/agentsync/releases/latest/download/agentsync-aarch64-apple-darwin.tar.gz
tar xzf agentsync-aarch64-apple-darwin.tar.gz
sudo mv agentsync-*/agentsync /usr/local/bin/

# macOS (Intel)
curl -LO https://github.com/dallay/agentsync/releases/latest/download/agentsync-x86_64-apple-darwin.tar.gz
tar xzf agentsync-x86_64-apple-darwin.tar.gz
sudo mv agentsync-*/agentsync /usr/local/bin/

# Linux (x86_64)
curl -LO https://github.com/dallay/agentsync/releases/latest/download/agentsync-x86_64-unknown-linux-gnu.tar.gz
tar xzf agentsync-x86_64-unknown-linux-gnu.tar.gz
sudo mv agentsync-*/agentsync /usr/local/bin/

# Linux (ARM64)
curl -LO https://github.com/dallay/agentsync/releases/latest/download/agentsync-aarch64-unknown-linux-gnu.tar.gz
tar xzf agentsync-aarch64-unknown-linux-gnu.tar.gz
sudo mv agentsync-*/agentsync /usr/local/bin/

From Source (requires Rust 1.85+)

cargo install --git https://github.com/dallay/agentsync

Or clone and build:

git clone https://github.com/dallay/agentsync
cd agentsync
cargo build --release
# Binary at ./target/release/agentsync

From crates.io

cargo install agentsync

Quick Start

1. Initialize configuration in your project:

cd your-project
agentsync init

This creates .agents/agentsync.toml with a default configuration.

2. Edit the configuration to match your needs (see Configuration)

3. Apply the configuration:

agentsync apply

4. Add to your project setup (e.g., package.json):

{
  "scripts": {
    "prepare": "agentsync apply || true"
  }
}

Usage

# Initialize a new configuration
agentsync init

# Apply configuration (create symlinks)
agentsync apply

# Clean existing symlinks before applying
agentsync apply --clean

# Remove all managed symlinks
agentsync clean

# Use a custom config file
agentsync apply --config /path/to/config.toml

# Dry run (show what would be done without making changes)
agentsync apply --dry-run

# Show version
agentsync --version

Configuration

Configuration is stored in .agents/agentsync.toml:

# Source directory (relative to this config file)
source_dir = "."

# Gitignore management
[gitignore]
enabled = true
marker = "AI Agent Symlinks"
entries = [
    "CLAUDE.md",
    "GEMINI.md",
    ".github/copilot-instructions.md",
]

# Agent definitions
[agents.claude]
enabled = true
description = "Claude Code - Anthropic's AI coding assistant"

[agents.claude.targets.instructions]
source = "AGENTS.md"
destination = "CLAUDE.md"
type = "symlink"

[agents.claude.targets.commands]
source = "command"
destination = ".claude/commands"
type = "symlink-contents"
pattern = "*.agent.md"

MCP Support (Model Context Protocol)

AgentSync can automatically generate MCP configuration files for supported agents (Claude Code, GitHub Copilot, Gemini CLI, VS Code).

This allows you to define MCP servers once in agentsync.toml and have them synchronized to all agent-specific config files.

[mcp]
enabled = true
# Strategy for existing files: "merge" (default) or "overwrite"
# "merge" preserves existing servers but overwrites conflicts with TOML config
merge_strategy = "merge"

# Define servers once
[mcp_servers.filesystem]
command = "npx"
args = ["-y", "@modelcontextprotocol/server-filesystem", "."]

[mcp_servers.git]
command = "npx"
args = ["-y", "@modelcontextprotocol/server-git", "--repository", "."]
# Optional fields:
# env = { "KEY" = "VALUE" }
# disabled = false

Supported Agents & File Locations

• Claude Code: .mcp.json
• GitHub Copilot: .copilot/mcp-config.json
• Gemini CLI: .gemini/settings.json (automatically adds trust: true)
• VS Code: .vscode/mcp.json
• OpenCode: .opencode/mcp.json

Merge Behavior

When merge_strategy = "merge":

1. AgentSync reads the existing config file (if it exists).
2. It adds servers defined in agentsync.toml.
3. Conflict Resolution: If a server name exists in both, the definition in agentsync.toml wins and overwrites the existing one.
4. Existing servers NOT in agentsync.toml are preserved.

Target Types

The symlink-contents type optionally supports a pattern field (glob pattern like *.md) to filter which files to link.

Project Structure

.agents/
├── agentsync.toml      # Configuration file
├── AGENTS.md           # Main agent instructions (single source)
├── .mcp.json           # MCP server configurations
├── command/            # Agent commands
│   ├── review.agent.md
│   └── test.agent.md
├── skills/             # Shared knowledge/skills
│   └── kotlin/
│       └── SKILL.md
└── prompts/            # Reusable prompts
    └── code-review.prompt.md

After running agentsync apply:

project-root/
├── CLAUDE.md           → .agents/AGENTS.md
├── GEMINI.md           → .agents/AGENTS.md
├── AGENTS.md           → .agents/AGENTS.md
├── .mcp.json           → .agents/.mcp.json
├── .claude/
│   └── commands/       → symlinks to .agents/command/*.agent.md
├── .gemini/
│   └── commands/       → symlinks to .agents/command/*.agent.md
└── .github/
    ├── copilot-instructions.md → .agents/AGENTS.md
    └── agents/         → symlinks to .agents/command/*.agent.md

CI/CD Integration

AgentSync gracefully handles CI environments where the binary isn't available:

{
  "scripts": {
    "agents:sync": "agentsync apply || echo 'agentsync not installed, skipping'",
    "prepare": "lefthook install && npm run agents:sync"
  }
}

The symlinks are primarily for local development. CI builds typically don't need them.

Installing in CI

If you need agentsync in CI, add it to your workflow:

- name: Install agentsync
  run: |
    curl -LO https://github.com/dallay/agentsync/releases/latest/download/agentsync-x86_64-unknown-linux-gnu.tar.gz
    tar xzf agentsync-x86_64-unknown-linux-gnu.tar.gz
    sudo mv agentsync-*/agentsync /usr/local/bin/

Getting Started (Development)

This project is a monorepo containing a Rust core and a JavaScript/TypeScript wrapper.

Prerequisites

• Rust (1.85+ recommended)
• Node.js (v18+)
• pnpm

Setup

1. Install JavaScript dependencies:

   pnpm install
   

2. Build the Rust binary:

   cargo build
   

Common Commands

This project uses a Makefile to orchestrate common tasks.

• Run Rust tests:

  make rust-test
  

• Run JavaScript tests:

  make js-test
  

• Build all components:

  make all
  

• Format the code:

  make fmt
  

Inspiration

• Ruler - Similar concept but copies files instead of using symlinks

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

1. Fork the repository
2. Create your feature branch (git checkout -b feat/amazing-feature)
3. Commit your changes (git commit -m 'feat: add amazing feature')
4. Push to the branch (git push origin feat/amazing-feature)
5. Open a Pull Request

License

MIT License - see LICENSE for details.