How to use MemoFS with Google Antigravity

Connect MemoFS to Google AntiGravity agents for persistent project memory across multi-agent workflows.

Google Antigravity is Google's AI-first development platform, available as Antigravity IDE (in-editor AI experience) and Antigravity CLI (agy) (terminal interface).

Antigravity automatically discovers project-scoped rules, skills, and MCP configurations inside the .agents/ folder. This cookbook guides you through setting up MemoFS with Antigravity IDE and Antigravity CLI.

How Antigravity Handles Rules & MCP

Rules: Antigravity loads project rules from AGENTS.md and .agents/rules/ (legacy GEMINI.md files are also supported for backwards compatibility).
MCP Servers in Antigravity IDE: Workspace-local MCP servers are configured in .agents/mcp_settings.json.
MCP Servers in Antigravity CLI: Global or profile-based MCP servers are registered using the agy mcp add command or stored in ~/.gemini/antigravity-cli/settings.json.

Setup Instructions

Step 1: Initialize project memory

Run the initializer in your project root:

cd /path/to/your/project
npx @memofs/cli init

Step 2: Generate agent rules

Generate the rules file for your workspace:

npx @memofs/cli generate agent-rules gemini --project-name "Your project name"

Note: If AGENTS.md is present in your project root, Antigravity loads it automatically. You can also link or copy rules into AGENTS.md and .agents/rules/.

Step 3: Register the MCP Server

Why `--root` is required for Antigravity:

Unlike Claude Code or Codex (which spawn MCP processes with cwd set to the project workspace), Antigravity spawns background MCP servers from its central daemon directory (~/.gemini/antigravity).

Without --root <path> or the MEMOFS_ROOT environment variable, MemoFS defaults to process.cwd() (~/.gemini/antigravity), which fails with UNEXPECTED_ERROR: Failed to create memory file parent directory. because Antigravity protects its system app directory from process writes. Always pass --root /absolute/path/to/your/project (or --root . when launched from the project root) or set MEMOFS_ROOT.

Depending on whether you are using Antigravity IDE or Antigravity CLI, follow the appropriate method below:

Option A: Antigravity IDE (Project-Local Configuration)

Add the MemoFS MCP server definition to .agents/mcp_settings.json (or .agents/mcp_config.json) in your project root:

.agents/mcp_settings.json

{
  "mcpServers": {
    "memofs": {
      "command": "npx",
      "args": ["-y", "@memofs/mcp-server", "--root", "/absolute/path/to/your/project"]
    }
  }
}

Or pass the workspace root dynamically via env:

.agents/mcp_settings.json

{
  "mcpServers": {
    "memofs": {
      "command": "npx",
      "args": ["-y", "@memofs/mcp-server"],
      "env": {
        "MEMOFS_ROOT": "/absolute/path/to/your/project"
      }
    }
  }
}

If .agents/mcp_settings.json does not exist yet, create it with the above content.

Option B: Antigravity CLI (`agy`)

agy mcp add memofs -- npx -y @memofs/mcp-server --root /absolute/path/to/your/project

Alternatively, run agy config --edit to edit your global CLI MCP profile.

Step 4: Record Memory & Verify

First, record a test decision:

npx @memofs/cli remember "Project uses VitePress for documentation" --kind note

In Antigravity IDE:

Open the sidebar chat panel in your IDE.
Ask the agent: "Which docs framework does this project use?"
Verify that the agent invokes the memofs MCP tools and returns the recorded fact.

In Antigravity CLI (`agy`):

Run agy inspect to verify active MCP tools and skills.
Confirm memofs is listed under active MCP servers.