AgentSync

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

Why AgentSync?

Different AI coding tools expect configuration files in various locations:

Tool	Instructions	Commands	Skills
Claude Code	CLAUDE.md	.claude/commands/	.claude/skills/
GitHub Copilot	.github/copilot-instructions.md	.github/agents/	-
Gemini CLI	GEMINI.md	.gemini/commands/	.gemini/skills/
Cursor	AGENTS.md	.cursor/commands/	.cursor/skills/
VS Code	AGENTS.md (or .vscode/*)	.vscode/	-
OpenCode	AGENTS.md	.opencode/command/	.opencode/skill/
OpenAI Codex	-	-	.codex/skills/

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
• 🛡️ Safe - Automatically backs up existing files before replacing them
• 🖥️ Cross-platform - Linux, macOS, Windows
• 🚀 CI-friendly - Gracefully skips when binary unavailable
• ⚡ Fast - Single static binary, no runtime dependencies

Installation

Node.js Package Managers (Recommended)

If you have Node.js (>=18) installed, the easiest way to install AgentSync is through a package manager.

Global Installation

# Using npm
npm install -g @dallay/agentsync

# Using pnpm
pnpm add -g @dallay/agentsync

# Using yarn (Classic v1)
yarn global add @dallay/agentsync

# Using bun
bun i -g @dallay/agentsync

One-off Execution

If you want to run AgentSync without a permanent global installation:

# Using npx (npm)
npx @dallay/agentsync apply

# Using dlx (pnpm)
pnpm dlx @dallay/agentsync apply

# Using dlx (yarn v2+)
yarn dlx @dallay/agentsync apply

# Using bunx (bun)
bunx @dallay/agentsync apply

Local Installation (Dev Dependency)

# Using npm
npm install --save-dev @dallay/agentsync

# Using pnpm
pnpm add -D @dallay/agentsync

# Using yarn
yarn add -D @dallay/agentsync

# Using bun
bun add -d @dallay/agentsync

From crates.io (Rust)

If you have Rust installed, you can install AgentSync directly from crates.io:

cargo install agentsync

From GitHub Releases (Pre-built Binaries)

Download the latest release for your platform from the GitHub Releases page.

To install via terminal, you can use the following script (replace VERSION with the latest version number, e.g., 1.28.0):

# Define version and platform
VERSION="1.28.0"
PLATFORM="x86_64-apple-darwin" # e.g., aarch64-apple-darwin, x86_64-unknown-linux-gnu
TARBALL="agentsync-${VERSION}-${PLATFORM}.tar.gz"

# Download binary and checksum
curl -LO "https://github.com/dallay/agentsync/releases/download/v${VERSION}/${TARBALL}"
curl -LO "https://github.com/dallay/agentsync/releases/download/v${VERSION}/${TARBALL}.sha256"

# Verify integrity
if command -v sha256sum >/dev/null; then
  sha256sum --check "${TARBALL}.sha256"
else
  shasum -a 256 --check "${TARBALL}.sha256"
fi

if [ $? -ne 0 ]; then
  echo "Error: Checksum verification failed!"
  exit 1
fi

# Extract and install
tar xzf "${TARBALL}"
sudo mv agentsync-*/agentsync /usr/local/bin/

From Source (Requires Rust 1.89+)

Install directly from the GitHub repository:

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

Or clone and build manually:

git clone https://github.com/dallay/agentsync
cd agentsync
cargo build --release

# The binary will be available at ./target/release/agentsync

Quick Start

New Projects

1. Initialize configuration in your project:

cd your-project
agentsync init

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

Existing Projects with Agent Files

If you already have agent configuration files scattered across your project (like CLAUDE.md, .cursor/, or .github/copilot-instructions.md), use the interactive wizard:

cd your-project
agentsync init --wizard

The wizard will scan for existing files, let you select which to migrate, and set up everything automatically.

---

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

# Initialize with interactive wizard (for existing projects with agent files)
agentsync init --wizard

# 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

# Filter by agent
agentsync apply --agents claude,copilot

# Disable gitignore updates
agentsync apply --no-gitignore

# Verbose output
agentsync apply --verbose

# Show status of managed symlinks
agentsync status

# Run diagnostic and health check
agentsync doctor [--project-root <path>]

# Manage skills
agentsync skill install <skill-id>
agentsync skill update <skill-id>
agentsync skill uninstall <skill-id>

Status

Verify the state of symlinks managed by AgentSync. Useful for local verification and CI.

agentsync status [--project-root <path>] [--json]

• --project-root <path>: Optional. Path to the project root to locate the agentsync config.
• --json: Output machine-readable JSON (pretty-printed).

Exit codes: 0 = no problems, 1 = problems detected (CI-friendly)

Configuration

Configuration is stored in .agents/agentsync.toml:

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

# Optional: compress AGENTS.md and point symlinks to the compressed file
# compress_agents_md = false

# Default agents to run when --agents is not specified.
# If empty, all enabled agents will be processed.
default_agents = ["claude", "copilot"]

# Gitignore management
[gitignore]
enabled = true
marker = "AI Agent Symlinks"
# Additional entries to add to .gitignore (target destinations are added automatically)
entries = []

# 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, OpenAI Codex CLI, Gemini CLI, Cursor, VS Code, OpenCode).

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 (canonical)

AgentSync supports the following agents and will synchronize corresponding files/locations. This list is canonical — keep it in sync with src/mcp.rs (authoritative).

• Claude Code — .mcp.json (agent id: claude)
• GitHub Copilot — .vscode/mcp.json (agent id: copilot)
• OpenAI Codex CLI — .codex/config.toml (agent id: codex) — TOML format with [mcp_servers.<name>] tables. AgentSync maps headers to Codex http_headers.
• Gemini CLI — .gemini/settings.json (agent id: gemini) — AgentSync will add trust: true when generating Gemini configs.
• Cursor — .cursor/mcp.json (agent id: cursor)
• VS Code — .vscode/mcp.json (agent id: vscode)
• OpenCode — opencode.json (agent id: opencode)

See website/docs/src/content/docs/guides/mcp.mdx for formatter details and merge behavior.

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

Type	Description
symlink	Create a symlink to the source file/directory
symlink-contents	Create symlinks for each file in the source directory

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 (source of truth for MCP)
├── AGENTS.md           # Main agent instructions (single source)
├── 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           (Generated from agentsync.toml)
├── .claude/
│   ├── commands/       → symlinks to .agents/command/*.agent.md
│   └── skills/         → symlinks to .agents/skills/*
├── .gemini/
│   ├── settings.json   (Generated from agentsync.toml)
│   ├── commands/       → symlinks to .agents/command/*.agent.md
│   └── skills/         → symlinks to .agents/skills/*
└── .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": "pnpm exec agentsync apply",
    "prepare": "lefthook install && pnpm 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, you can download the latest version automatically using jq for robust parsing:

- name: Install agentsync
  env:
    GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
  run: |
    # Fetch latest version using GitHub API and jq
    LATEST_TAG=$(curl -s -H "Authorization: Bearer $GH_TOKEN" \
      https://api.github.com/repos/dallay/agentsync/releases/latest | jq -r '.tag_name')
    
    if [ "$LATEST_TAG" == "null" ] || [ -z "$LATEST_TAG" ]; then
      echo "Error: Failed to fetch latest release tag"
      exit 1
    fi
    
    VERSION=${LATEST_TAG#v}
    PLATFORM="x86_64-unknown-linux-gnu"
    
    curl -LO "https://github.com/dallay/agentsync/releases/download/${LATEST_TAG}/agentsync-${VERSION}-${PLATFORM}.tar.gz"
    tar xzf agentsync-${VERSION}-${PLATFORM}.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.

Repository Structure

• src/: Core logic and CLI implementation in Rust.
• npm/agentsync/: TypeScript wrapper used for NPM distribution.
• website/docs/: Documentation site built with Starlight.
• tests/: Integration tests for the CLI.

Prerequisites

• Rust (1.89+ recommended)
• Node.js (v24.13.0+ recommended for development)
• 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

Troubleshooting

PNPM_NO_MATURE_MATCHING_VERSION

If pnpm install fails with this error, it's likely due to a strict package release age policy. You can try installing with --ignore-scripts or wait for the package to "mature" in the registry.

Lefthook installation failure

If pnpm install fails during the lefthook setup, you can try:

pnpm install --ignore-scripts

Symlink creation fails on Windows

Ensure you have Developer Mode enabled or run your terminal as Administrator, as Windows requires special permissions for creating symbolic links.

Inspiration

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

Contributing

Contributions are welcome! Please see CONTRIBUTING.md for guidelines on how to get started.

License

MIT License - see LICENSE for details.