diff --git a/dsl/attribute.go b/dsl/attribute.go
index 2f904b59d8..a6bc780fc4 100644
--- a/dsl/attribute.go
+++ b/dsl/attribute.go
@@ -301,7 +301,7 @@ func Example(args ...any) {
 		return
 	}
 	if len(args) > 2 {
-		eval.ReportError("too many arguments")
+		eval.TooManyArgError()
 		return
 	}
 	var (
@@ -400,7 +400,7 @@ func parseAttributeArgs(baseAttr *expr.AttributeExpr, args ...any) (expr.DataTyp
 		parseDescription("string", 1)
 		parseDSL(2, success, func() { eval.InvalidArgError("func()", args[2]) })
 	default:
-		eval.ReportError("too many arguments in call to Attribute")
+		eval.TooManyArgError()
 	}
 
 	return dataType, description, fn
diff --git a/dsl/http.go b/dsl/http.go
index e2b53c91a6..2266e4b4e2 100644
--- a/dsl/http.go
+++ b/dsl/http.go
@@ -743,7 +743,7 @@ func Param(name string, args ...any) {
 //	})
 func MapParams(args ...any) {
 	if len(args) > 1 {
-		eval.ReportError("too many arguments")
+		eval.TooManyArgError()
 	}
 	e, ok := eval.Current().(*expr.HTTPEndpointExpr)
 	if !ok {
diff --git a/dsl/http_file_server.go b/dsl/http_file_server.go
index e360104765..611bbf0057 100644
--- a/dsl/http_file_server.go
+++ b/dsl/http_file_server.go
@@ -49,7 +49,7 @@ import (
 //	})
 func Files(path, filename string, fns ...func()) {
 	if len(fns) > 1 {
-		eval.ReportError("too many arguments given to Files")
+		eval.TooManyArgError()
 		return
 	}
 	// Make sure request path starts with a "/" so codegen can rely on it.
diff --git a/dsl/payload.go b/dsl/payload.go
index a4adf2682c..dded16e9d4 100644
--- a/dsl/payload.go
+++ b/dsl/payload.go
@@ -70,7 +70,7 @@ import (
 //	})
 func Payload(val any, args ...any) {
 	if len(args) > 2 {
-		eval.ReportError("too many arguments")
+		eval.TooManyArgError()
 	}
 	e, ok := eval.Current().(*expr.MethodExpr)
 	if !ok {
@@ -124,7 +124,7 @@ func Payload(val any, args ...any) {
 //	})
 func StreamingPayload(val any, args ...any) {
 	if len(args) > 2 {
-		eval.ReportError("too many arguments")
+		eval.TooManyArgError()
 	}
 	e, ok := eval.Current().(*expr.MethodExpr)
 	if !ok {
diff --git a/dsl/response.go b/dsl/response.go
index fcd85cd3d6..fc00f266ca 100644
--- a/dsl/response.go
+++ b/dsl/response.go
@@ -234,7 +234,7 @@ func parseResponseArgs(val any, args ...any) (code int, fn func()) {
 	case int:
 		code = t
 		if len(args) > 1 {
-			eval.ReportError("too many arguments given to Response (%d)", len(args)+1)
+			eval.TooManyArgError()
 			return
 		}
 		if len(args) == 1 {
diff --git a/dsl/result.go b/dsl/result.go
index 3c987cbf3d..845e40f758 100644
--- a/dsl/result.go
+++ b/dsl/result.go
@@ -72,7 +72,7 @@ import (
 //	})
 func Result(val any, args ...any) {
 	if len(args) > 2 {
-		eval.ReportError("too many arguments")
+		eval.TooManyArgError()
 		return
 	}
 	e, ok := eval.Current().(*expr.MethodExpr)
@@ -130,7 +130,7 @@ func Result(val any, args ...any) {
 //	})
 func StreamingResult(val any, args ...any) {
 	if len(args) > 2 {
-		eval.ReportError("too many arguments")
+		eval.TooManyArgError()
 		return
 	}
 	e, ok := eval.Current().(*expr.MethodExpr)
diff --git a/dsl/result_type.go b/dsl/result_type.go
index 5fab7eabab..de883d2864 100644
--- a/dsl/result_type.go
+++ b/dsl/result_type.go
@@ -98,7 +98,7 @@ func ResultType(identifier string, args ...any) *expr.ResultTypeExpr {
 					eval.InvalidArgError("function", args[1])
 				}
 				if len(args) > 2 {
-					eval.ReportError("too many arguments")
+					eval.TooManyArgError()
 				}
 			}
 		}
diff --git a/dsl/security.go b/dsl/security.go
index 0a31738e79..224f2f31e4 100644
--- a/dsl/security.go
+++ b/dsl/security.go
@@ -524,13 +524,13 @@ func Scope(name string, desc ...string) {
 	switch current := eval.Current().(type) {
 	case *expr.SecurityExpr:
 		if len(desc) >= 1 {
-			eval.ReportError("too many arguments")
+			eval.TooManyArgError()
 			return
 		}
 		current.Scopes = append(current.Scopes, name)
 	case *expr.SchemeExpr:
 		if len(desc) > 1 {
-			eval.ReportError("too many arguments")
+			eval.TooManyArgError()
 			return
 		}
 		d := "no description"
diff --git a/dsl/server.go b/dsl/server.go
index d529717874..f230c71af0 100644
--- a/dsl/server.go
+++ b/dsl/server.go
@@ -58,7 +58,7 @@ import (
 //	})
 func Server(name string, fn ...func()) *expr.ServerExpr {
 	if len(fn) > 1 {
-		eval.ReportError("too many arguments given to Server")
+		eval.TooManyArgError()
 	}
 	api, ok := eval.Current().(*expr.APIExpr)
 	if !ok {
diff --git a/dsl/user_type.go b/dsl/user_type.go
index 2aa733c4cd..7659ea7e4b 100644
--- a/dsl/user_type.go
+++ b/dsl/user_type.go
@@ -58,7 +58,7 @@ var (
 //	})
 func Type(name string, args ...any) expr.UserType {
 	if len(args) > 2 {
-		eval.ReportError("too many arguments")
+		eval.TooManyArgError()
 		return nil
 	}
 	if t := expr.Root.UserType(name); t != nil {
@@ -149,7 +149,7 @@ func ArrayOf(v any, fn ...func()) *expr.Array {
 		return &expr.Array{ElemType: &expr.AttributeExpr{Type: expr.String}}
 	}
 	if len(fn) > 1 {
-		eval.ReportError("ArrayOf: too many arguments")
+		eval.TooManyArgError()
 		return &expr.Array{ElemType: &expr.AttributeExpr{Type: expr.String}}
 	}
 	at := expr.AttributeExpr{Type: t}
@@ -203,7 +203,7 @@ func MapOf(k, v any, fn ...func()) *expr.Map {
 		return &expr.Map{KeyType: &expr.AttributeExpr{Type: expr.String}, ElemType: &expr.AttributeExpr{Type: expr.String}}
 	}
 	if len(fn) > 1 {
-		eval.ReportError("MapOf: too many arguments")
+		eval.TooManyArgError()
 		return &expr.Map{KeyType: &expr.AttributeExpr{Type: expr.String}, ElemType: &expr.AttributeExpr{Type: expr.String}}
 	}
 	kat := expr.AttributeExpr{Type: tk}
diff --git a/eval/eval.go b/eval/eval.go
index 34cb8f03cd..a3e622baca 100644
--- a/eval/eval.go
+++ b/eval/eval.go
@@ -125,6 +125,12 @@ func InvalidArgError(expected string, actual any) {
 	ReportError("cannot use %#v (type %s) as type %s", actual, reflect.TypeOf(actual), expected)
 }
 
+// TooManyArgError records a too many arguments error. It is used by DSL
+// functions that take dynamic arguments.
+func TooManyArgError() {
+	ReportError("too many arguments given to %s", caller())
+}
+
 // ValidationErrors records the errors encountered when running Validate.
 type ValidationErrors struct {
 	Errors      []error
@@ -234,7 +240,7 @@ func finalizeSet(set ExpressionSet) {
 
 // caller returns the name of calling function.
 func caller() string {
-	for skip := 2; skip <= 3; skip++ {
+	for skip := 2; skip <= 4; skip++ {
 		pc, _, _, ok := runtime.Caller(skip)
 		if !ok {
 			break
diff --git a/expr/http_file_server_test.go b/expr/http_file_server_test.go
index fdee36c0de..15e289df34 100644
--- a/expr/http_file_server_test.go
+++ b/expr/http_file_server_test.go
@@ -16,6 +16,7 @@ func TestFilesDSL(t *testing.T) {
 	}{
 		{Name: "valid", DSL: testdata.FilesValidDSL},
 		{Name: "incompatible", DSL: testdata.FilesIncompatibleDSL, Error: "invalid use of Files in API files-incompatile"},
+		{Name: "too many arg error", DSL: testdata.FilesTooManyArgErrorDSL, Error: "too many arguments given to Files in API files-too-many-arg-error"},
 	}
 	for _, c := range cases {
 		t.Run(c.Name, func(t *testing.T) {
diff --git a/expr/testdata/http_file_server.go b/expr/testdata/http_file_server.go
index 1e3950d5c1..f822d43dae 100644
--- a/expr/testdata/http_file_server.go
+++ b/expr/testdata/http_file_server.go
@@ -15,3 +15,9 @@ var FilesIncompatibleDSL = func() {
 		Files("path", "filename")
 	})
 }
+
+var FilesTooManyArgErrorDSL = func() {
+	API("files-too-many-arg-error", func() {
+		Files("path", "filename", func() {}, func() {})
+	})
+}