Antigravity

Add Walrus Memory to Antigravity so the agent recalls context and saves durable facts. Install it as a plugin (adds automatic-memory hooks) or as MCP-only (just the tools).

Prerequisites

• Node.js 22.23.4+ (22.x), 24.22.1+ (24.x), or 26.12.1+ (26.x)
• A Walrus Memory account. The first memory tool call opens a browser sign-in (memwal_login).

How to install Walrus Memory in Antigravity

Plugin (recommended)

Deploy the plugin (MCP server + lifecycle hooks) into Antigravity's plugin directory:

npx degit MystenLabs/MemWal/packages/mcp/plugin ~/.gemini/config/plugins/memwal

Restart Antigravity, then ask the agent to run memwal_login on first use.

MCP-only

Add the Walrus Memory server to Antigravity's MCP configuration as a local stdio command:

{
  "mcpServers": {
    "memwal": {
      "command": "npx",
      "args": ["-y", "@mysten-incubation/memwal-mcp"],
      "env": { "MEMWAL_NAMESPACE": "default" }
    }
  }
}

Restart Antigravity, then ask the agent to run memwal_login on first use.

What the plugin includes

Component	Plugin	MCP-only
Walrus Memory MCP (memory tools)	✓	✓
Lifecycle hooks (automatic recall/save)	✓	✗

What lifecycle hooks does the plugin provide?

Hook	Event	What it does
Session start	SessionStart	Announces that memory is active and reminds the agent to use the memwal_* tools.
User prompt	UserPromptSubmit	Injects a decision rubric so the agent chooses recall vs save from meaning (any language or spelling).
Post-tool	PostToolUse (Bash)	When a command errors, reminds the agent to recall prior fixes and save the resolution.

Available tools

Tool	Description
memwal_remember	Save a durable fact (preference, decision, constraint, identity).
memwal_remember_bulk	Save several distinct facts in one call.
memwal_recall	Semantic search across stored memories for relevant context.
memwal_analyze	Extract and save multiple facts from a passage of text.
memwal_restore	Rebuild the search index from Walrus (recovery).
memwal_health	Fast connectivity check.
memwal_login / memwal_logout	Connect or disconnect this client.

The tool descriptions tell the agent to save and recall proactively. See Reference for full parameters.

How to verify the connection

Ask the agent what MCP tools it has available. You should see the memwal_* tools. State a durable fact and confirm the agent saves it with memwal_remember. To confirm that the fact persists, ask the agent to check the save with memwal_remember_status, then recall it and check that memwal_recall returns it. If the status never completes, ask the agent to run memwal_health to check connectivity.

Troubleshooting

• Tools missing: restart Antigravity after installation.
• Not signed in: ask the agent to run memwal_login, approve in the browser, then retry.
• memwal_recall returns nothing although you saved before: run memwal_restore <namespace> to rebuild the index from Walrus.

Choose a memory namespace

Every recall runs inside one account and namespace. The MEMWAL_NAMESPACE value in the MCP-only config sets the default namespace. The package injects it into memwal_remember, memwal_remember_bulk, memwal_recall, memwal_analyze, and memwal_restore calls that do not already carry one. To keep this client's memories in their own space, set a distinct name such as work or project-x. Avoid keeping everything in default after early testing.

You can also pass "--namespace", "<name>" in args. The CLI flag wins over the environment variable. An explicit namespace in a tool call always overrides the configured default. If you set neither, the relayer applies its own default namespace.