diff --git a/mrun/mrun.go b/mrun/mrun.go
index 2d2b84c..6f60e3b 100644
--- a/mrun/mrun.go
+++ b/mrun/mrun.go
@@ -40,7 +40,7 @@ type ctxKey int
 // be canceled as well.
 //
 // See Wait for accompanying functionality.
-func Thread(ctx mctx.Context, fn func(mctx.Context) error) {
+func Thread(ctx mctx.Context, fn func() error) {
 	futErr := newFutureErr()
 	mctx.GetSetMutableValue(ctx, false, ctxKey(0), func(i interface{}) interface{} {
 		futErrs, ok := i.([]*futureErr)
@@ -51,7 +51,7 @@ func Thread(ctx mctx.Context, fn func(mctx.Context) error) {
 	})
 
 	go func() {
-		futErr.set(fn(ctx))
+		futErr.set(fn())
 	}()
 }
 
diff --git a/mrun/mrun_test.go b/mrun/mrun_test.go
index 70981e3..372089b 100644
--- a/mrun/mrun_test.go
+++ b/mrun/mrun_test.go
@@ -29,7 +29,7 @@ func TestThreadWait(t *T) {
 		t.Run("noBlock", func(t *T) {
 			t.Run("noErr", func(t *T) {
 				ctx := mctx.New()
-				Thread(ctx, func(mctx.Context) error { return nil })
+				Thread(ctx, func() error { return nil })
 				if err := Wait(ctx, nil); err != nil {
 					t.Fatal(err)
 				}
@@ -37,7 +37,7 @@ func TestThreadWait(t *T) {
 
 			t.Run("err", func(t *T) {
 				ctx := mctx.New()
-				Thread(ctx, func(mctx.Context) error { return testErr })
+				Thread(ctx, func() error { return testErr })
 				if err := Wait(ctx, nil); err != testErr {
 					t.Fatalf("should have got test error, got: %v", err)
 				}
@@ -47,7 +47,7 @@ func TestThreadWait(t *T) {
 		t.Run("block", func(t *T) {
 			t.Run("noErr", func(t *T) {
 				ctx := mctx.New()
-				Thread(ctx, func(mctx.Context) error {
+				Thread(ctx, func() error {
 					time.Sleep(1 * time.Second)
 					return nil
 				})
@@ -58,7 +58,7 @@ func TestThreadWait(t *T) {
 
 			t.Run("err", func(t *T) {
 				ctx := mctx.New()
-				Thread(ctx, func(mctx.Context) error {
+				Thread(ctx, func() error {
 					time.Sleep(1 * time.Second)
 					return testErr
 				})
@@ -69,7 +69,7 @@ func TestThreadWait(t *T) {
 
 			t.Run("canceled", func(t *T) {
 				ctx := mctx.New()
-				Thread(ctx, func(mctx.Context) error {
+				Thread(ctx, func() error {
 					time.Sleep(5 * time.Second)
 					return testErr
 				})
@@ -89,7 +89,7 @@ func TestThreadWait(t *T) {
 		t.Run("noBlock", func(t *T) {
 			t.Run("noErr", func(t *T) {
 				ctx, childCtx := ctxWithChild()
-				Thread(childCtx, func(mctx.Context) error { return nil })
+				Thread(childCtx, func() error { return nil })
 				if err := Wait(ctx, nil); err != nil {
 					t.Fatal(err)
 				}
@@ -97,7 +97,7 @@ func TestThreadWait(t *T) {
 
 			t.Run("err", func(t *T) {
 				ctx, childCtx := ctxWithChild()
-				Thread(childCtx, func(mctx.Context) error { return testErr })
+				Thread(childCtx, func() error { return testErr })
 				if err := Wait(ctx, nil); err != testErr {
 					t.Fatalf("should have got test error, got: %v", err)
 				}
@@ -107,7 +107,7 @@ func TestThreadWait(t *T) {
 		t.Run("block", func(t *T) {
 			t.Run("noErr", func(t *T) {
 				ctx, childCtx := ctxWithChild()
-				Thread(childCtx, func(mctx.Context) error {
+				Thread(childCtx, func() error {
 					time.Sleep(1 * time.Second)
 					return nil
 				})
@@ -118,7 +118,7 @@ func TestThreadWait(t *T) {
 
 			t.Run("err", func(t *T) {
 				ctx, childCtx := ctxWithChild()
-				Thread(childCtx, func(mctx.Context) error {
+				Thread(childCtx, func() error {
 					time.Sleep(1 * time.Second)
 					return testErr
 				})
@@ -129,7 +129,7 @@ func TestThreadWait(t *T) {
 
 			t.Run("canceled", func(t *T) {
 				ctx, childCtx := ctxWithChild()
-				Thread(childCtx, func(mctx.Context) error {
+				Thread(childCtx, func() error {
 					time.Sleep(5 * time.Second)
 					return testErr
 				})