diff --git a/package-lock.json b/package-lock.json
index 924c847..2c709ad 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "@clawnify/clawflow",
-  "version": "1.6.4",
+  "version": "1.6.5",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@clawnify/clawflow",
-      "version": "1.6.4",
+      "version": "1.6.5",
       "license": "MIT",
       "dependencies": {
         "croner": "^10.0.1"
diff --git a/package.json b/package.json
index 5c41693..9ca0c20 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@clawnify/clawflow",
-  "version": "1.6.4",
+  "version": "1.6.5",
   "description": "The n8n for agents. A declarative, AI-native workflow format that agents can read, write, and run.",
   "type": "module",
   "main": "./dist/index.js",
diff --git a/src/core/custom-steps.ts b/src/core/custom-steps.ts
index a6a07f1..32bc586 100644
--- a/src/core/custom-steps.ts
+++ b/src/core/custom-steps.ts
@@ -141,8 +141,23 @@ export class StepRegistry {
   }
 }
 
-/** Module-level default registry shared by host applications. */
-export const defaultRegistry = new StepRegistry();
+/**
+ * Process-wide default registry shared by host applications.
+ *
+ * Held on `globalThis` under a registered symbol, not as a plain module
+ * singleton. Node caches ES modules by resolved path, so a plugin importing
+ * ClawFlow from `src/index.ts` and a gateway running `dist/index.js` used to
+ * get two registries: the plugin's steps landed in one the engine never
+ * read, and flows failed validation with "Unknown node type". House plugins
+ * flipped between the two paths more than once (agent-tools fixed in
+ * July, openclaw-email still wrong in September). With one registry per
+ * process the import path no longer matters, and neither does a second
+ * copy of the package on disk.
+ */
+const REGISTRY_KEY = Symbol.for("@clawnify/clawflow/step-registry");
+type RegistryHolder = { [REGISTRY_KEY]?: StepRegistry };
+const holder = globalThis as unknown as RegistryHolder;
+export const defaultRegistry: StepRegistry = holder[REGISTRY_KEY] ?? (holder[REGISTRY_KEY] = new StepRegistry());
 
 /**
  * Register a custom step type on the default registry. Call once at startup.
diff --git a/tests/registry-shared.test.ts b/tests/registry-shared.test.ts
new file mode 100644
index 0000000..e3187e8
--- /dev/null
+++ b/tests/registry-shared.test.ts
@@ -0,0 +1,19 @@
+import { describe, it } from "node:test";
+import assert from "node:assert/strict";
+
+// Two imports of the same module file under different specifiers are two
+// module instances in Node — exactly what a plugin importing clawflow from
+// src/ while the gateway runs dist/ produces. The default registry must be
+// the same object in both.
+describe("default step registry", () => {
+  it("is shared across separately loaded module instances", async () => {
+    const a = await import("../src/core/custom-steps.js?instance=a");
+    const b = await import("../src/core/custom-steps.js?instance=b");
+    assert.notEqual(a, b, "test setup: expected two module instances");
+    assert.equal(a.defaultRegistry, b.defaultRegistry);
+
+    a.registerStepType({ name: "shared_probe_step", allowedKeys: [], run: () => 1 });
+    assert.ok(b.defaultRegistry.has("shared_probe_step"), "a step registered through one instance is visible through the other");
+    a.defaultRegistry.clear();
+  });
+});