diff --git a/src/plugins/http-registry.test.ts b/src/plugins/http-registry.test.ts
new file mode 100644
index 00000000000..fca12e4dc11
--- /dev/null
+++ b/src/plugins/http-registry.test.ts
@@ -0,0 +1,78 @@
+import { describe, expect, it, vi } from "vitest";
+import { registerPluginHttpRoute } from "./http-registry.js";
+import { createEmptyPluginRegistry } from "./registry.js";
+
+describe("registerPluginHttpRoute", () => {
+  it("registers route and unregisters it", () => {
+    const registry = createEmptyPluginRegistry();
+    const handler = vi.fn();
+
+    const unregister = registerPluginHttpRoute({
+      path: "/plugins/demo",
+      handler,
+      registry,
+    });
+
+    expect(registry.httpRoutes).toHaveLength(1);
+    expect(registry.httpRoutes[0]?.path).toBe("/plugins/demo");
+    expect(registry.httpRoutes[0]?.handler).toBe(handler);
+
+    unregister();
+    expect(registry.httpRoutes).toHaveLength(0);
+  });
+
+  it("returns noop unregister when path is missing", () => {
+    const registry = createEmptyPluginRegistry();
+    const logs: string[] = [];
+    const unregister = registerPluginHttpRoute({
+      path: "",
+      handler: vi.fn(),
+      registry,
+      accountId: "default",
+      log: (msg) => logs.push(msg),
+    });
+
+    expect(registry.httpRoutes).toHaveLength(0);
+    expect(logs).toEqual(['plugin: webhook path missing for account "default"']);
+    expect(() => unregister()).not.toThrow();
+  });
+
+  it("replaces stale route on same path and keeps latest registration", () => {
+    const registry = createEmptyPluginRegistry();
+    const logs: string[] = [];
+    const firstHandler = vi.fn();
+    const secondHandler = vi.fn();
+
+    const unregisterFirst = registerPluginHttpRoute({
+      path: "/plugins/synology",
+      handler: firstHandler,
+      registry,
+      accountId: "default",
+      pluginId: "synology-chat",
+      log: (msg) => logs.push(msg),
+    });
+
+    const unregisterSecond = registerPluginHttpRoute({
+      path: "/plugins/synology",
+      handler: secondHandler,
+      registry,
+      accountId: "default",
+      pluginId: "synology-chat",
+      log: (msg) => logs.push(msg),
+    });
+
+    expect(registry.httpRoutes).toHaveLength(1);
+    expect(registry.httpRoutes[0]?.handler).toBe(secondHandler);
+    expect(logs).toContain(
+      'plugin: replacing stale webhook path /plugins/synology for account "default" (synology-chat)',
+    );
+
+    // Old unregister must not remove the replacement route.
+    unregisterFirst();
+    expect(registry.httpRoutes).toHaveLength(1);
+    expect(registry.httpRoutes[0]?.handler).toBe(secondHandler);
+
+    unregisterSecond();
+    expect(registry.httpRoutes).toHaveLength(0);
+  });
+});
diff --git a/src/plugins/http-registry.ts b/src/plugins/http-registry.ts
index 5e2df3b522d..5987fd17370 100644
--- a/src/plugins/http-registry.ts
+++ b/src/plugins/http-registry.ts
@@ -29,10 +29,11 @@ export function registerPluginHttpRoute(params: {
     return () => {};
   }
 
-  if (routes.some((entry) => entry.path === normalizedPath)) {
+  const existingIndex = routes.findIndex((entry) => entry.path === normalizedPath);
+  if (existingIndex >= 0) {
     const pluginHint = params.pluginId ? ` (${params.pluginId})` : "";
-    params.log?.(`plugin: webhook path ${normalizedPath} already registered${suffix}${pluginHint}`);
-    return () => {};
+    params.log?.(`plugin: replacing stale webhook path ${normalizedPath}${suffix}${pluginHint}`);
+    routes.splice(existingIndex, 1);
   }
 
   const entry: PluginHttpRouteRegistration = {