diff --git a/docgen/docgen.go b/docgen/docgen.go
index 2fd9bf076..f4c78c8a1 100644
--- a/docgen/docgen.go
+++ b/docgen/docgen.go
@@ -32,6 +32,22 @@ type Type struct {
 	Return    *Type                `json:"return,omitempty"`
 }
 
+var (
+	Operators = []string{"matches", "contains", "startsWith", "endsWith"}
+	Builtins  = map[Identifier]*Type{
+		"true":   {Kind: "bool"},
+		"false":  {Kind: "bool"},
+		"len":    {Kind: "func", Arguments: []*Type{{Kind: "array", Type: &Type{Kind: "any"}}}, Return: &Type{Kind: "int"}},
+		"all":    {Kind: "func", Arguments: []*Type{{Kind: "array", Type: &Type{Kind: "any"}}, {Kind: "func"}}, Return: &Type{Kind: "bool"}},
+		"none":   {Kind: "func", Arguments: []*Type{{Kind: "array", Type: &Type{Kind: "any"}}, {Kind: "func"}}, Return: &Type{Kind: "bool"}},
+		"any":    {Kind: "func", Arguments: []*Type{{Kind: "array", Type: &Type{Kind: "any"}}, {Kind: "func"}}, Return: &Type{Kind: "bool"}},
+		"one":    {Kind: "func", Arguments: []*Type{{Kind: "array", Type: &Type{Kind: "any"}}, {Kind: "func"}}, Return: &Type{Kind: "bool"}},
+		"filter": {Kind: "func", Arguments: []*Type{{Kind: "array", Type: &Type{Kind: "any"}}, {Kind: "func"}}, Return: &Type{Kind: "array", Type: &Type{Kind: "any"}}},
+		"map":    {Kind: "func", Arguments: []*Type{{Kind: "array", Type: &Type{Kind: "any"}}, {Kind: "func"}}, Return: &Type{Kind: "array", Type: &Type{Kind: "any"}}},
+		"count":  {Kind: "func", Arguments: []*Type{{Kind: "array", Type: &Type{Kind: "any"}}, {Kind: "func"}}, Return: &Type{Kind: "int"}},
+	}
+)
+
 func CreateDoc(i interface{}) *Context {
 	c := &Context{
 		Variables: make(map[Identifier]*Type),
@@ -42,6 +58,16 @@ func CreateDoc(i interface{}) *Context {
 		c.Variables[Identifier(name)] = c.use(t.Type, fromMethod(t.Method))
 	}
 
+	for _, op := range Operators {
+		c.Variables[Identifier(op)] = &Type{
+			Kind: "operator",
+		}
+	}
+
+	for builtin, t := range Builtins {
+		c.Variables[builtin] = t
+	}
+
 	return c
 }
 
diff --git a/docgen/docgen_test.go b/docgen/docgen_test.go
index 00fe379ea..b3cc3ff34 100644
--- a/docgen/docgen_test.go
+++ b/docgen/docgen_test.go
@@ -33,6 +33,8 @@ func (*Env) Duration(s string) Duration {
 }
 
 func TestCreateDoc(t *testing.T) {
+	Operators = nil
+	Builtins = nil
 	doc := CreateDoc(&Env{})
 	expected := &Context{
 		Variables: map[Identifier]*Type{
@@ -96,6 +98,8 @@ func TestCreateDoc_FromMap(t *testing.T) {
 		}{},
 		"Max": math.Max,
 	}
+	Operators = nil
+	Builtins = nil
 	doc := CreateDoc(env)
 	expected := &Context{
 		Variables: map[Identifier]*Type{