diff --git a/ext/integrations/exec_integration.c b/ext/integrations/exec_integration.c
index f195e9e6e5a..8e53ef36c96 100644
--- a/ext/integrations/exec_integration.c
+++ b/ext/integrations/exec_integration.c
@@ -7,9 +7,10 @@
 #include <ext/standard/file.h>
 #include <ext/standard/proc_open.h>
 
-#include "compatibility.h"
-#include "ddtrace.h"
-#include "span.h"
+#include "../compatibility.h"
+#include "../ddtrace.h"
+#include "../span.h"
+#include "exec_integration_arginfo.h"
 
 #define NS "DDTrace\\Integrations\\Exec\\"
 
@@ -262,33 +263,16 @@ static PHP_FUNCTION(DDTrace_integrations_exec_test_rshutdown) {
 
     ddtrace_exec_handlers_rshutdown();
     dd_exec_init_track_streams();
-    (void)return_value;
+    RETURN_TRUE;
 }
 
 // clang-format off
-ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(register_stream, 0, 2, _IS_BOOL, 0)
-    ZEND_ARG_TYPE_INFO(0, stream, IS_RESOURCE, 0)
-    ZEND_ARG_OBJ_INFO(0, span, DDTrace\\SpanData, 0)
-ZEND_END_ARG_INFO()
-ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(proc_assoc_span, 0, 2, _IS_BOOL, 1)
-    ZEND_ARG_TYPE_INFO(0, proc_res, IS_RESOURCE, 0)
-    ZEND_ARG_OBJ_INFO(0, span, DDTrace\\SpanData, 0)
-ZEND_END_ARG_INFO()
-ZEND_BEGIN_ARG_WITH_RETURN_OBJ_INFO_EX(proc_get_span, 0, 1, DDTrace\\SpanData, 0)
-    ZEND_ARG_TYPE_INFO(0, proc_res, IS_RESOURCE, 0)
-ZEND_END_ARG_INFO()
-ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(proc_get_pid, 0, 1, IS_LONG, 1)
-    ZEND_ARG_TYPE_INFO(0, proc_res, IS_RESOURCE, 0)
-ZEND_END_ARG_INFO()
-ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(test_rshutdown, 0, 0, IS_NULL, 1)
-ZEND_END_ARG_INFO()
-
 static const zend_function_entry functions[] = {
-    ZEND_RAW_FENTRY(NS "register_stream", PHP_FN(DDTrace_integrations_exec_register_stream), register_stream, 0)
-    ZEND_RAW_FENTRY(NS "proc_assoc_span", PHP_FN(DDTrace_integrations_exec_proc_assoc_span), proc_assoc_span, 0)
-    ZEND_RAW_FENTRY(NS "proc_get_span", PHP_FN(DDTrace_integrations_exec_proc_get_span), proc_get_span, 0)
-    ZEND_RAW_FENTRY(NS "proc_get_pid", PHP_FN(DDTrace_integrations_exec_proc_get_pid), proc_get_pid, 0)
-    ZEND_RAW_FENTRY(NS "test_rshutdown", PHP_FN(DDTrace_integrations_exec_test_rshutdown), test_rshutdown, 0)
+    ZEND_RAW_FENTRY(NS "register_stream", PHP_FN(DDTrace_integrations_exec_register_stream), arginfo_DDTrace_Integrations_Exec_register_stream, 0)
+    ZEND_RAW_FENTRY(NS "proc_assoc_span", PHP_FN(DDTrace_integrations_exec_proc_assoc_span), arginfo_DDTrace_Integrations_Exec_proc_assoc_span, 0)
+    ZEND_RAW_FENTRY(NS "proc_get_span", PHP_FN(DDTrace_integrations_exec_proc_get_span), arginfo_DDTrace_Integrations_Exec_proc_get_span, 0)
+    ZEND_RAW_FENTRY(NS "proc_get_pid", PHP_FN(DDTrace_integrations_exec_proc_get_pid), arginfo_DDTrace_Integrations_Exec_proc_get_pid, 0)
+    ZEND_RAW_FENTRY(NS "test_rshutdown", PHP_FN(DDTrace_integrations_exec_test_rshutdown), arginfo_DDTrace_Integrations_Exec_test_rshutdown, 0)
     PHP_FE_END
 };
 // clang-format on
diff --git a/ext/integrations/exec_integration.stub.php b/ext/integrations/exec_integration.stub.php
new file mode 100644
index 00000000000..92d935f681f
--- /dev/null
+++ b/ext/integrations/exec_integration.stub.php
@@ -0,0 +1,60 @@
+<?php
+
+namespace DDTrace\Integrations\Exec {
+
+    /**
+     * Associates a popen() stream resource with a span so that when the resource is destroyed, the span is updated
+     * with the exit code and closed.
+     *
+     * It is not validated that the stream is actually a popen() stream resource.
+     *
+     * Only one span can be associated with a stream resource. A subsequent call replaces the first span.
+     *
+     * @internal for use by the exec integration only
+     * @param resource $stream A stream resource
+     * @param \DDTrace\SpanData $span The command_execution span to associate
+     * @return bool true on success or false if the resource is not a stream
+     */
+    function register_stream($stream, \DDTrace\SpanData $span): bool {}
+
+    /**
+     * Associates a proc_open() process handle with a span so that when the handle is closed, there is a waitpid()
+     * call on the child, and the span is updated with the exit code and closed.
+     *
+     * Only one call to this function can be made per process handle. A subsequent call has undefined behavior.
+     *
+     * @internal for use by the exec integration only
+     * @param resource $proc_h A process handle
+     * @param \DDTrace\SpanData $span The command_execution span to associate
+     * @return bool true on success or false if the resource is not a process handle
+     */
+    function proc_assoc_span($proc_h, \DDTrace\SpanData $span) : bool {}
+
+    /**
+     * Retrieves a span previously associated with a process handle by proc_assoc_span(), or
+     * null if there's none.
+     *
+     * @internal for use by the exec integration only
+     * @param resource $proc_h A process handle
+     * @return \DDTrace\SpanData|null The associated span, if any.
+     */
+    function proc_get_span($proc_h) : ?\DDTrace\SpanData {}
+
+    /**
+     * Retrieves the pid associated with a process handle.
+     *
+     * @internal for use by the testes of the exec integration only
+     * @param resource $proc_h A process handle
+     * @return int|null The associated span, if any.
+     */
+    function proc_get_pid($proc_h) : ?int {}
+
+    /**
+     * Closes the spans associated with live resources opened by popen() and proc_open()
+     *
+     * @internal for use by the testes of the exec integration only
+     * @return bool
+     */
+    function test_rshutdown() : bool {}
+}
+
diff --git a/ext/integrations/exec_integration_arginfo.h b/ext/integrations/exec_integration_arginfo.h
new file mode 100644
index 00000000000..e1764294cc5
--- /dev/null
+++ b/ext/integrations/exec_integration_arginfo.h
@@ -0,0 +1,23 @@
+/* This is a generated file, edit the .stub.php file instead.
+ * Stub hash: 97cc0e5375b6d1d07fa0db5a4dba3e102709674f */
+
+ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(arginfo_DDTrace_Integrations_Exec_register_stream, 0, 2, _IS_BOOL, 0)
+	ZEND_ARG_INFO(0, stream)
+	ZEND_ARG_OBJ_INFO(0, span, DDTrace\\SpanData, 0)
+ZEND_END_ARG_INFO()
+
+ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(arginfo_DDTrace_Integrations_Exec_proc_assoc_span, 0, 2, _IS_BOOL, 0)
+	ZEND_ARG_INFO(0, proc_h)
+	ZEND_ARG_OBJ_INFO(0, span, DDTrace\\SpanData, 0)
+ZEND_END_ARG_INFO()
+
+ZEND_BEGIN_ARG_WITH_RETURN_OBJ_INFO_EX(arginfo_DDTrace_Integrations_Exec_proc_get_span, 0, 1, DDTrace\\SpanData, 1)
+	ZEND_ARG_INFO(0, proc_h)
+ZEND_END_ARG_INFO()
+
+ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(arginfo_DDTrace_Integrations_Exec_proc_get_pid, 0, 1, IS_LONG, 1)
+	ZEND_ARG_INFO(0, proc_h)
+ZEND_END_ARG_INFO()
+
+ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(arginfo_DDTrace_Integrations_Exec_test_rshutdown, 0, 0, _IS_BOOL, 0)
+ZEND_END_ARG_INFO()