diff --git a/src/browser/profiles-service.test.ts b/src/browser/profiles-service.test.ts
index 13bbdf27c49..029488dd527 100644
--- a/src/browser/profiles-service.test.ts
+++ b/src/browser/profiles-service.test.ts
@@ -201,20 +201,27 @@ describe("BrowserProfilesService", () => {
     );
   });
 
-  it("rejects driver=existing-session when cdpUrl is provided", async () => {
+  it("allows driver=existing-session when cdpUrl is provided as an MCP target", async () => {
     const resolved = resolveBrowserConfig({});
-    const { ctx } = createCtx(resolved);
+    const { ctx, state } = createCtx(resolved);
     vi.mocked(loadConfig).mockReturnValue({ browser: { profiles: {} } });
 
     const service = createBrowserProfilesService(ctx);
+    const result = await service.createProfile({
+      name: "chrome-live",
+      driver: "existing-session",
+      cdpUrl: "http://127.0.0.1:9222",
+    });
 
-    await expect(
-      service.createProfile({
-        name: "chrome-live",
-        driver: "existing-session",
-        cdpUrl: "http://127.0.0.1:9222",
-      }),
-    ).rejects.toThrow(/does not accept cdpUrl/i);
+    expect(result.transport).toBe("chrome-mcp");
+    expect(result.cdpUrl).toBeNull();
+    expect(result.isRemote).toBe(false);
+    expect(state.resolved.profiles["chrome-live"]).toEqual({
+      cdpUrl: "http://127.0.0.1:9222",
+      driver: "existing-session",
+      attachOnly: true,
+      color: expect.any(String),
+    });
   });
 
   it("deletes remote profiles without stopping or removing local data", async () => {
diff --git a/src/browser/profiles-service.ts b/src/browser/profiles-service.ts
index 86321006e98..27ad1b75120 100644
--- a/src/browser/profiles-service.ts
+++ b/src/browser/profiles-service.ts
@@ -130,15 +130,19 @@ export function createBrowserProfilesService(ctx: BrowserRouteContext) {
         }
       }
       if (driver === "existing-session") {
-        throw new BrowserValidationError(
-          "driver=existing-session does not accept cdpUrl; it attaches via the Chrome MCP auto-connect flow",
-        );
+        profileConfig = {
+          cdpUrl: parsed.normalized,
+          driver,
+          attachOnly: true,
+          color: profileColor,
+        };
+      } else {
+        profileConfig = {
+          cdpUrl: parsed.normalized,
+          ...(driver ? { driver } : {}),
+          color: profileColor,
+        };
       }
-      profileConfig = {
-        cdpUrl: parsed.normalized,
-        ...(driver ? { driver } : {}),
-        color: profileColor,
-      };
     } else {
       if (driver === "extension") {
         throw new BrowserValidationError("driver=extension requires an explicit loopback cdpUrl");