rivet-dev · jog1t · Aug 28, 2026 · Aug 28, 2026
diff --git a/.claude/reference/feature-flags.md b/.claude/reference/feature-flags.md
@@ -33,6 +33,7 @@ if (features.platform) {
 | `branding` | Rivet branding chrome. |
 | `datacenter` | Datacenter-related UI. |
 | `danger-zone` | Destructive settings actions (`features.dangerZone`). |
+| `mcp` | MCP connection settings card on the namespace settings drawer. Flavor-dependent content: `platform` renders the hosted `mcp.rivet.dev` endpoint pinned to this namespace, everything else renders the local stdio (`npx @rivet-dev/mcp`) config. |
 
 Deployment flavors map to flag sets roughly as: **cloud** = all on; **OSS** = `auth`/`platform`/`acl` off; **enterprise** = `acl` on, `auth`/`platform` off (engine enforces auth without a login UI). Do not treat `platform`/`auth` as "engine requires credentials" — that is `acl`. **`compute` is opt-in even on cloud** — each Railway service adds it to `VITE_FEATURE_FLAGS` per-environment (e.g. staging on, prod off) rather than inheriting the cloud default-on set.
 
@@ -48,15 +49,18 @@ Switch flavors in dev without restarting the server by setting the `localStorage
 // OSS self-host: everything off
 localStorage.setItem("FEATURE_FLAGS", ""); location.reload();
 
+// OSS self-host with the local MCP snippet shown
+localStorage.setItem("FEATURE_FLAGS", "mcp"); location.reload();
+
 // Full cloud: all flags on (see the commented canonical list in frontend/.env.local)
 localStorage.setItem(
   "FEATURE_FLAGS",
-  "compute,platform,acl,auth,captcha,branding,support,billing,datacenter,danger-zone,multitenancy",
+  "compute,platform,acl,auth,captcha,branding,support,billing,datacenter,danger-zone,multitenancy,mcp",
 );
 location.reload();
 
 // Enterprise: acl on, no login UI
-localStorage.setItem("FEATURE_FLAGS", "acl,branding,support,datacenter,danger-zone"); location.reload();
+localStorage.setItem("FEATURE_FLAGS", "acl,branding,support,datacenter,danger-zone,mcp"); location.reload();
 ```
 
 In an agent-browser / DevTools session, paste those into the page console. `localStorage` persists across reloads, so run `localStorage.removeItem("FEATURE_FLAGS")` to return to the env default when finished. Confirm the active flavor with `JSON.stringify(features)` after importing, or just observe whether auth/cloud chrome is present.

diff --git a/frontend/apps/inspector-ui/mcp-index.html b/frontend/apps/inspector-ui/mcp-index.html
@@ -0,0 +1,57 @@
+<!doctype html>
+<html lang="en" class="dark">
+	<head>
+		<meta charset="UTF-8" />
+		<meta name="viewport" content="width=device-width, initial-scale=1.0" />
+		<title>Rivet Actor Inspector</title>
+		<script>
+			// MCP hosts may frame this app with `sandbox="allow-scripts"` and no
+			// `allow-same-origin`, which makes every `Window.localStorage` read throw
+			// a SecurityError. Shadow the accessors with in-memory stores before any
+			// module runs so storage reads degrade to per-session state.
+			(() => {
+				const memory = () => {
+					const entries = new Map();
+					return {
+						get length() {
+							return entries.size;
+						},
+						key(index) {
+							return [...entries.keys()][index] ?? null;
+						},
+						getItem(key) {
+							return entries.has(String(key))
+								? entries.get(String(key))
+								: null;
+						},
+						setItem(key, value) {
+							entries.set(String(key), String(value));
+						},
+						removeItem(key) {
+							entries.delete(String(key));
+						},
+						clear() {
+							entries.clear();
+						},
+					};
+				};
+				for (const name of ["localStorage", "sessionStorage"]) {
+					try {
+						const probe = "__rivet_storage_probe__";
+						window[name].setItem(probe, "1");
+						window[name].removeItem(probe);
+					} catch {
+						Object.defineProperty(window, name, {
+							configurable: true,
+							value: memory(),
+						});
+					}
+				}
+			})();
+		</script>
+	</head>
+	<body>
+		<div id="root"></div>
+		<script type="module" src="/src/mcp-main.tsx"></script>
+	</body>
+</html>
diff --git a/frontend/apps/inspector-ui/src/main.tsx b/frontend/apps/inspector-ui/src/main.tsx
diff --git a/frontend/apps/inspector-ui/src/mcp-main.tsx b/frontend/apps/inspector-ui/src/mcp-main.tsx