diff --git a/include/amduat/pel/program_dag.h b/include/amduat/pel/program_dag.h
index f5f51cb..a690b54 100644
--- a/include/amduat/pel/program_dag.h
+++ b/include/amduat/pel/program_dag.h
@@ -78,25 +78,6 @@ typedef struct {
 
 bool amduat_pel_program_dag_validate(const amduat_pel_program_t *program);
 
-bool amduat_pel_program_dag_exec(
-    const amduat_pel_program_t *program,
-    const amduat_artifact_t *inputs,
-    size_t inputs_len,
-    const amduat_artifact_t *params,
-    amduat_artifact_t **out_outputs,
-    size_t *out_outputs_len,
-    amduat_pel_execution_result_value_t *out_result);
-
-bool amduat_pel_program_dag_exec_trace(
-    const amduat_pel_program_t *program,
-    const amduat_artifact_t *inputs,
-    size_t inputs_len,
-    const amduat_artifact_t *params,
-    amduat_artifact_t **out_outputs,
-    size_t *out_outputs_len,
-    amduat_pel_execution_result_value_t *out_result,
-    amduat_pel_program_dag_trace_t *out_trace);
-
 void amduat_pel_program_dag_free_outputs(amduat_artifact_t *outputs,
                                          size_t outputs_len);
 
diff --git a/src/internal/pel_program_dag_internal.h b/src/internal/pel_program_dag_internal.h
new file mode 100644
index 0000000..477dc55
--- /dev/null
+++ b/src/internal/pel_program_dag_internal.h
@@ -0,0 +1,33 @@
+#ifndef AMDUAT_INTERNAL_PEL_PROGRAM_DAG_INTERNAL_H
+#define AMDUAT_INTERNAL_PEL_PROGRAM_DAG_INTERNAL_H
+
+#include "amduat/pel/program_dag.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+bool amduat_pel_program_dag_exec(
+    const amduat_pel_program_t *program,
+    const amduat_artifact_t *inputs,
+    size_t inputs_len,
+    const amduat_artifact_t *params,
+    amduat_artifact_t **out_outputs,
+    size_t *out_outputs_len,
+    amduat_pel_execution_result_value_t *out_result);
+
+bool amduat_pel_program_dag_exec_trace(
+    const amduat_pel_program_t *program,
+    const amduat_artifact_t *inputs,
+    size_t inputs_len,
+    const amduat_artifact_t *params,
+    amduat_artifact_t **out_outputs,
+    size_t *out_outputs_len,
+    amduat_pel_execution_result_value_t *out_result,
+    amduat_pel_program_dag_trace_t *out_trace);
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif /* AMDUAT_INTERNAL_PEL_PROGRAM_DAG_INTERNAL_H */
diff --git a/src/pel_stack/run.c b/src/pel_stack/run.c
index 8209fa9..c4ca34a 100644
--- a/src/pel_stack/run.c
+++ b/src/pel_stack/run.c
@@ -3,7 +3,7 @@
 #include "amduat/asl/artifact_io.h"
 #include "amduat/enc/pel1_result.h"
 #include "amduat/enc/pel_program_dag.h"
-#include "amduat/pel/program_dag.h"
+#include "pel_program_dag_internal.h"
 #include "amduat/pel/program_dag_desc.h"
 
 #include <stdarg.h>
diff --git a/src/pel_stack/surf/surf.c b/src/pel_stack/surf/surf.c
index c983b4d..2678ada 100644
--- a/src/pel_stack/surf/surf.c
+++ b/src/pel_stack/surf/surf.c
@@ -3,7 +3,7 @@
 #include "amduat/enc/pel1_result.h"
 #include "amduat/enc/pel_program_dag.h"
 #include "amduat/enc/pel_trace_dag.h"
-#include "amduat/pel/program_dag.h"
+#include "pel_program_dag_internal.h"
 #include "amduat/pel/program_dag_desc.h"
 
 #include <stdarg.h>
diff --git a/tests/pel/test_pel_program_dag_exec.c b/tests/pel/test_pel_program_dag_exec.c
index 31332fb..bc8bc4e 100644
--- a/tests/pel/test_pel_program_dag_exec.c
+++ b/tests/pel/test_pel_program_dag_exec.c
@@ -1,4 +1,4 @@
-#include "amduat/pel/program_dag.h"
+#include "pel_program_dag_internal.h"
 #include <stdbool.h>
 #include <stdint.h>
 #include <stdio.h>