diff --git a/VERSION b/VERSION
index cea0e15..d8ba80f 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-v2.0.6
+v2.0.7
diff --git a/figs.go b/figs.go
index 53af31b..6e2be35 100644
--- a/figs.go
+++ b/figs.go
@@ -74,6 +74,8 @@ func With(opts Options) Plant {
 		problems:       make([]error, 0),
 		figs:           make(map[string]*figFruit),
 		withered:       make(map[string]witheredFig),
+		sources:        make(map[string]SourceConfig),
+		sourceLocker:   sync.RWMutex{},
 		mu:             sync.RWMutex{},
 		mutationsCh:    make(chan Mutation),
 		flagSet:        flag.NewFlagSet(os.Args[0], flag.ContinueOnError),
diff --git a/internals_test.go b/internals_test.go
index a879d41..e064697 100644
--- a/internals_test.go
+++ b/internals_test.go
@@ -17,14 +17,16 @@ func TestTree_checkAndSetFromEnv(t *testing.T) {
 	// create a new fig tree
 	var figs *figTree
 	figs = &figTree{
-		harvest:     1,
-		figs:        make(map[string]*figFruit),
-		tracking:    false,
-		withered:    make(map[string]witheredFig),
-		flagSet:     flag.NewFlagSet(os.Args[0], flag.ContinueOnError),
-		mu:          sync.RWMutex{},
-		mutationsCh: make(chan Mutation, 1),
-		filterTests: true,
+		harvest:      1,
+		figs:         make(map[string]*figFruit),
+		tracking:     false,
+		withered:     make(map[string]witheredFig),
+		sources:      make(map[string]SourceConfig),
+		sourceLocker: sync.RWMutex{},
+		flagSet:      flag.NewFlagSet(os.Args[0], flag.ContinueOnError),
+		mu:           sync.RWMutex{},
+		mutationsCh:  make(chan Mutation, 1),
+		filterTests:  true,
 	}
 
 	// assign an int to k
@@ -61,6 +63,8 @@ func TestTree_setValue(t *testing.T) {
 		ConfigFilePath string
 		figs           map[string]*figFruit
 		withered       map[string]witheredFig
+		sources        map[string]SourceConfig
+		sourceLocker   sync.RWMutex
 		mu             sync.RWMutex
 		tracking       bool
 		mutationsCh    chan Mutation
@@ -79,9 +83,11 @@ func TestTree_setValue(t *testing.T) {
 		{
 			name: "Set int value",
 			fields: fields{
-				figs:        make(map[string]*figFruit),
-				withered:    make(map[string]witheredFig),
-				mutationsCh: make(chan Mutation, 1),
+				figs:         make(map[string]*figFruit),
+				withered:     make(map[string]witheredFig),
+				mutationsCh:  make(chan Mutation, 1),
+				sources:      make(map[string]SourceConfig),
+				sourceLocker: sync.RWMutex{},
 			},
 			args: args{
 				flagVal: new(int),
@@ -93,9 +99,11 @@ func TestTree_setValue(t *testing.T) {
 		{
 			name: "Set string value",
 			fields: fields{
-				figs:        make(map[string]*figFruit),
-				withered:    make(map[string]witheredFig),
-				mutationsCh: make(chan Mutation, 1),
+				figs:         make(map[string]*figFruit),
+				withered:     make(map[string]witheredFig),
+				mutationsCh:  make(chan Mutation, 1),
+				sources:      make(map[string]SourceConfig),
+				sourceLocker: sync.RWMutex{},
 			},
 			args: args{
 				flagVal: new(string),
@@ -107,9 +115,11 @@ func TestTree_setValue(t *testing.T) {
 		{
 			name: "Invalid type",
 			fields: fields{
-				figs:        make(map[string]*figFruit),
-				withered:    make(map[string]witheredFig),
-				mutationsCh: make(chan Mutation, 1),
+				figs:         make(map[string]*figFruit),
+				withered:     make(map[string]witheredFig),
+				mutationsCh:  make(chan Mutation, 1),
+				sources:      make(map[string]SourceConfig),
+				sourceLocker: sync.RWMutex{},
 			},
 			args: args{
 				flagVal: new(float32), // Unsupported type
@@ -150,13 +160,15 @@ func TestTree_setValue(t *testing.T) {
 
 func TestTree_setValuesFromMap(t *testing.T) {
 	tree := &figTree{
-		figs:        make(map[string]*figFruit),
-		withered:    make(map[string]witheredFig),
-		mu:          sync.RWMutex{},
-		tracking:    false,
-		mutationsCh: make(chan Mutation, 1),
-		flagSet:     flag.NewFlagSet(os.Args[0], flag.ContinueOnError),
-		filterTests: true,
+		figs:         make(map[string]*figFruit),
+		withered:     make(map[string]witheredFig),
+		sources:      make(map[string]SourceConfig),
+		sourceLocker: sync.RWMutex{},
+		mu:           sync.RWMutex{},
+		tracking:     false,
+		mutationsCh:  make(chan Mutation, 1),
+		flagSet:      flag.NewFlagSet(os.Args[0], flag.ContinueOnError),
+		filterTests:  true,
 	}
 	m := map[string]interface{}{
 		"name": "yahuah",
diff --git a/list_flag.go b/list_flag.go
index 01231b6..c56344a 100644
--- a/list_flag.go
+++ b/list_flag.go
@@ -34,12 +34,17 @@ func (l *ListFlag) String() string {
 	return strings.Join(*l.values, ",")
 }
 
+// PolicyListAppend will apply ListFlag.Set to the list of values and not append to any existing values in the ListFlag
+var PolicyListAppend bool = false
+
 // Set unpacks a comma separated value argument and appends items to the list of []string
 func (l *ListFlag) Set(value string) error {
 	if l.values == nil {
 		l.values = &[]string{}
 	}
 	items := strings.Split(value, ",")
-	*l.values = append(*l.values, items...)
+	if PolicyListAppend {
+		*l.values = append(*l.values, items...)
+	}
 	return nil
 }
diff --git a/source.go b/source.go
new file mode 100644
index 0000000..24f8f18
--- /dev/null
+++ b/source.go
@@ -0,0 +1,42 @@
+package figtree
+
+type SourceKind int
+
+const (
+	SourceKindUnknown SourceKind = iota
+	SourceKindEnv
+	SourceKindFile
+	SourceKindFlag
+	SourceKindFlagEnv
+)
+
+type SourceConfig interface {
+	Fetch() (string, error)
+	Kind() SourceKind
+}
+
+func (tree *figTree) WithSource(source SourceConfig) error {
+	return nil
+}
+
+func (tree *figTree) Source(name string) error {
+	tree.mu.RLock()
+	source, exists := tree.sources[name]
+	tree.mu.RUnlock()
+	if !exists {
+		return ErrSourceNotFound{}
+	}
+	result, err := source.Fetch()
+	if err != nil {
+		return err
+	}
+	tree.StoreString(name, result)
+
+	return nil
+}
+
+type ErrSourceNotFound struct{}
+
+func (e ErrSourceNotFound) Error() string {
+	return "source not found"
+}
diff --git a/types.go b/types.go
index 4e2476a..e5d2610 100644
--- a/types.go
+++ b/types.go
@@ -26,6 +26,9 @@ type Plant interface {
 	// Fig returns a figFruit from the figTree by its name
 	Fig(name string) Flesh
 
+	// Source runs the attached WithSource against the SourceConfig
+	Source(name string) error
+
 	// WithValidator binds a figValidatorFunc to a figFruit that returns Plant
 	WithValidator(name string, validator func(interface{}) error) Plant
 
@@ -142,6 +145,8 @@ type figTree struct {
 	pollinate      bool
 	figs           map[string]*figFruit
 	withered       map[string]witheredFig
+	sources        map[string]SourceConfig
+	sourceLocker   sync.RWMutex
 	mu             sync.RWMutex
 	tracking       bool
 	problems       []error