diff --git a/appinventor/schemekit/src/SCMProcedure.h b/appinventor/schemekit/src/SCMProcedure.h
index 2970090370..a30c41cbf9 100644
--- a/appinventor/schemekit/src/SCMProcedure.h
+++ b/appinventor/schemekit/src/SCMProcedure.h
@@ -16,6 +16,11 @@ NS_ASSUME_NONNULL_BEGIN
 - (instancetype)initWithProcedure:(pic_value)procedure interpreter:(SCMInterpreter *)interpreter;
 - (nullable id<SCMValue>)invoke;
 - (nullable id<SCMValue>)invokeWithArguments:(NSArray<id> * _Nonnull)arguments;
+- (NSInteger)numberOfArguments;
+- (BOOL)variadic;
+
+@property(readonly) NSInteger numberOfArguments;
+@property(readonly) BOOL variadic;
 
 @end
 
diff --git a/appinventor/schemekit/src/SCMProcedure.m b/appinventor/schemekit/src/SCMProcedure.m
index 70d4d20e26..d0a6e16eab 100644
--- a/appinventor/schemekit/src/SCMProcedure.m
+++ b/appinventor/schemekit/src/SCMProcedure.m
@@ -4,6 +4,9 @@
 // http://www.apache.org/licenses/LICENSE-2.0
 
 #import "SCMProcedure.h"
+#import "picrin.h"
+#include "picrin/private/object.h"
+#include "picrin/private/vm.h"
 #import "SCMInterpreter-Private.h"
 
 @interface SCMProcedure () {
@@ -90,4 +93,20 @@ - (nonnull id)copyWithZone:(nullable NSZone *)zone {
   return [interpreter_ apply:self.value to:arguments];
 }
 
+- (NSInteger)numberOfArguments {
+  if (pic_type(interpreter_.state, value_) == PIC_TYPE_IREP) {
+    struct proc *proc = pic_proc_ptr(interpreter_.state, value_);
+    return (NSInteger) proc->u.i.irep->argc - 1;
+  }
+  return 0;
+}
+
+- (BOOL)variadic {
+  if (pic_type(interpreter_.state, value_) == PIC_TYPE_IREP) {
+    struct proc *proc = pic_proc_ptr(interpreter_.state, value_);
+    return proc->u.i.irep->varg;
+  }
+  return NO;
+}
+
 @end
diff --git a/appinventor/schemekit/tests/SCMProcedureTests.m b/appinventor/schemekit/tests/SCMProcedureTests.m
index f60ef5c84b..72bc0d0604 100644
--- a/appinventor/schemekit/tests/SCMProcedureTests.m
+++ b/appinventor/schemekit/tests/SCMProcedureTests.m
@@ -40,4 +40,22 @@ - (void)testApplyWithArgs {
   XCTAssertEqual(4, result.intValue);
 }
 
+- (void)testNumArgs {
+  [interpreter evalForm:@"(yail:invoke *test-environment* 'setObject:forKey: (lambda (x y) (+ x y)) \"proc3\")"];
+  XCTAssertNil(interpreter.exception);
+  SCMProcedure *proc = (SCMProcedure *) env[@"proc3"];
+  XCTAssertNotNil(proc);
+  XCTAssertEqual(2, proc.numberOfArguments);
+  XCTAssertFalse(proc.variadic);
+}
+
+- (void)testVariadic {
+  [interpreter evalForm:@"(yail:invoke *test-environment* 'setObject:forKey: (lambda (x y . z) #f) \"proc4\")"];
+  XCTAssertNil(interpreter.exception);
+  SCMProcedure *proc = (SCMProcedure *) env[@"proc4"];
+  XCTAssertNotNil(proc);
+  XCTAssertEqual(2, proc.numberOfArguments);
+  XCTAssertTrue([proc variadic]);
+}
+
 @end