Document the antigravity MCP config as stdio via mcp-remote

reference/mcp-server/clients/antigravity.mdx

@@ -3,11 +3,9 @@ title: "Google Antigravity"
 description: "Connect Google Antigravity to the Kernel MCP server"
 ---
 
-<Warning>
-Antigravity can complete the OAuth flow and still send `initialize` without the bearer token attached, which comes back as `401 Unauthorized` ([antigravity-cli#25](https://github.com/google-antigravity/antigravity-cli/issues/25)).
-
-If you hit that, [connect with an API key](#connect-with-an-api-key-workaround) instead of OAuth.
-</Warning>
+<Note>
+Kernel connects to Antigravity over stdio through `mcp-remote` rather than as a remote `serverUrl` server. Antigravity's remote-server client can complete the OAuth flow and still send `initialize` without the bearer token attached, which comes back as `401 Unauthorized` ([antigravity-cli#25](https://github.com/google-antigravity/antigravity-cli/issues/25)). `mcp-remote` runs the OAuth flow itself, so the token does not depend on that client.
+</Note>
 
 ## Install with the Kernel CLI
 
@@ -25,35 +23,60 @@ Alternatively, open the agent side panel, click the ellipsis (**…**) menu, and
 {
   "mcpServers": {
     "kernel": {
-      "serverUrl": "https://mcp.onkernel.com/mcp"
+      "command": "npx",
+      "args": [
+        "-y",
+        "mcp-remote",
+        "https://mcp.onkernel.com/mcp",
+        "--static-oauth-client-metadata",
+        "{\"client_name\":\"Antigravity\"}"
+      ]
     }
   }
 }
 ```
 
-Antigravity uses `serverUrl` for remote servers; `url` and `httpUrl` are ignored. Reload the window to pick up the change.
+If the entry previously used `serverUrl`, remove that key. Reload the window to pick up the change.
+
+`--static-oauth-client-metadata` names the OAuth client. Without it, `mcp-remote` registers as **MCP CLI Proxy** and the Kernel consent screen asks you to trust that name instead of Antigravity.
 
 ## Connect
 
-Press **⌘/Ctrl ,** to open agent settings, go to the **Customizations** tab, and click **Authenticate** next to **kernel**.
+Go to **Settings → Customizations**, scroll to **Installed MCP Servers**, and click the reload button.
+
+`mcp-remote` opens a browser window for you to authorize access. Once it completes, Kernel shows as connected in the **Installed MCP Servers** list. Tokens are cached under `~/.mcp-auth` and refreshed for you.
+
+## Connect with an API key
 
-Authorize access in the browser window that opens, then copy the authorization code, paste it back into the settings panel, and click **Submit**. Antigravity stores the tokens in `~/.gemini/antigravity/mcp_oauth_tokens.json` and refreshes them for you.
+For headless or scripted use, where no browser is available to complete the OAuth flow, authenticate with a project-scoped Kernel API key from the [Kernel Dashboard](https://dashboard.onkernel.com/api-keys) instead. `kernel mcp install --target antigravity` always writes the OAuth config, so wire this up by hand.
 
-## Connect with an API key (workaround)
+Put the key in a header file that only you can read:
 
-Get a project-scoped Kernel API key from the [Kernel Dashboard](https://dashboard.onkernel.com/api-keys) and pass it as a header instead of authenticating. `kernel mcp install --target antigravity` always writes the OAuth config, so add the `headers` block by hand:
+```bash
+mkdir -p ~/.kernel
+install -m 600 /dev/null ~/.kernel/mcp-headers.txt
+echo "Authorization: Bearer YOUR_KERNEL_API_KEY" > ~/.kernel/mcp-headers.txt
+```
+
+Then point `mcp-remote` at it:
 
 ```json
 {
   "mcpServers": {
     "kernel": {
-      "serverUrl": "https://mcp.onkernel.com/mcp",
-      "headers": {
-        "Authorization": "Bearer YOUR_KERNEL_API_KEY"
-      }
+      "command": "npx",
+      "args": [
+        "-y",
+        "mcp-remote",
+        "https://mcp.onkernel.com/mcp",
+        "--header-file",
+        "/Users/you/.kernel/mcp-headers.txt"
+      ]
     }
   }
 }
 ```
 
-Leave the **Authenticate** button alone when using this — Antigravity sends the header on every request, including `initialize`.
+Use an absolute path. `mcp-remote` opens the file directly, so a leading `~` isn't expanded and a relative path resolves against whatever directory Antigravity launched it from.
+
+`--header Authorization:...` takes the value inline instead, but the key then sits in the process arguments, where any other account on the machine can read it from the process list.