Antigravity 2.0 context/notebooks/visualization MCP servers fail with ENOENT socket when the IDE is not running

[stupidity-ai]

Title: Antigravity 2.0 context/notebooks/visualization MCP servers fail with ENOENT socket when the IDE is not running

Product/versions:

• Antigravity 2.0 (hub): v2.4.3, macOS arm64
• Antigravity IDE: latest, macOS arm64
• googlecloudtools.datacloud extension: 0.7.2-universal

Error (seen in the hub MCP connection error panel, servers: context, notebooks, visualization):

Error: [MCP Proxy] Socket connection error: connect ENOENT /var/folders/.../T/datacloud-mcp-context-antigravityide.sock : connection closed: calling "initialize": client is closing: EOF

Root cause (reproduced):

The hub's context, notebooks, visualization MCP servers are thin proxies (mcp_proxy_bundle.cjs, 5 attempts / 1s retry) that connect to Unix sockets named datacloud-mcp-{context,notebooks,visualization}-antigravityide.sock. Those sockets are bound only by the datacloud extension running inside the Antigravity IDE (exthost log: [MCP Registry] Listening on socket: .../datacloud-mcp-context-antigravityide.sock). The hub itself never binds these sockets.

Verified:

1. IDE running + window open → all 3 sockets exist and answer MCP initialize (serverInfo: context-mcp-server).
2. IDE quit → sockets disappear; hub proxies retry 5 times then die with the ENOENT error above. No sockets are ever created by the hub alone.
3. Hub alone (IDE closed) → hub spawns proxy node processes but sockets are never bound.
4. Closing the IDE window (even while the IDE app process stays alive) disposes the exthost and kills the sockets.

So Antigravity 2.0 silently depends on the Antigravity IDE being open for three of its default MCP servers to function, with no fallback (e.g., the hub hosting/binding its own datacloud backend, or gracefully disabling the servers).

Secondary trigger (auth race at startup):

At IDE launch without an active gcloud account, the datacloud extension fails to initialize and its MCP servers die mid-initialize (EOF), leaving no working sockets:

[error] Failed to get gcloud config: Error: Command gcloud failed with code 1: ERROR: (gcloud.config.config-helper) You do not currently have an active account selected.

This was resolved by gcloud auth login + ADC, but the extension did not recover until both apps were fully restarted.

Expected behavior:

• Hub MCP servers should either be self-contained (bind their own sockets) or start/stop gracefully (e.g., disable the servers with a clear message when the IDE isn't running), instead of surfacing connect ENOENT ... client is closing: EOF errors.