diff --git a/.changeset/six-peas-make.md b/.changeset/six-peas-make.md
new file mode 100644
index 0000000000..23f2fe2756
--- /dev/null
+++ b/.changeset/six-peas-make.md
@@ -0,0 +1,5 @@
+---
+"@workflow/core": patch
+---
+
+Make registeredSteps a global singleton to protect against module duplication and caching issues
diff --git a/packages/core/src/private.ts b/packages/core/src/private.ts
index 97b028b018..3ccaadd1e0 100644
--- a/packages/core/src/private.ts
+++ b/packages/core/src/private.ts
@@ -15,8 +15,19 @@ export type StepFunction<
   stepId?: string;
 };
 
-const registeredSteps = new Map<string, StepFunction>();
-const BUILTIN_RESPONSE_STEP_NAMES = new Set([
+const RegisteredStepsKey = Symbol.for('@workflow/core//registeredSteps');
+
+const globalSymbols: typeof globalThis & {
+  [RegisteredStepsKey]?: Map<string, StepFunction>;
+} = globalThis;
+
+// biome-ignore lint/suspicious/noAssignInExpressions: /
+const registeredSteps = (globalSymbols[RegisteredStepsKey] ??= new Map<
+  string,
+  StepFunction
+>());
+
+const BUILTIN_STEP_NAMES = new Set([
   '__builtin_response_array_buffer',
   '__builtin_response_json',
   '__builtin_response_text',
@@ -59,7 +70,7 @@ function getStepIdAliasCandidates(stepId: string): string[] {
 }
 
 function getBuiltinResponseStepAlias(stepId: string): StepFunction | undefined {
-  if (!BUILTIN_RESPONSE_STEP_NAMES.has(stepId)) {
+  if (!BUILTIN_STEP_NAMES.has(stepId)) {
     return undefined;
   }