diff --git a/dag/graph.go b/dag/graph.go
index 4906eb293..9d6ef2da4 100644
--- a/dag/graph.go
+++ b/dag/graph.go
@@ -343,13 +343,17 @@ func (g *Graph) SetDebugWriter(w io.Writer) {
 	g.debug.Encode(newMarshalGraph("root", g))
 }
 
-func (g *Graph) AnnotateVertex(v Vertex, info string) {
-	va := newVertexAnnotation(v, info)
+// DebugVertexInfo encodes arbitrary information about a vertex in the graph
+// debug logs.
+func (g *Graph) DebugVertexInfo(v Vertex, info string) {
+	va := newVertexDebugInfo(v, info)
 	g.debug.Encode(va)
 }
 
-func (g *Graph) AnnotateEdge(e Edge, info string) {
-	ea := newEdgeAnnotation(e, info)
+// DebugEdgeInfo encodes arbitrary information about an edge in the graph debug
+// logs.
+func (g *Graph) DebugEdgeInfo(e Edge, info string) {
+	ea := newEdgeDebugInfo(e, info)
 	g.debug.Encode(ea)
 }
 
diff --git a/dag/marshal.go b/dag/marshal.go
index 47daadcbc..7e18ed0fc 100644
--- a/dag/marshal.go
+++ b/dag/marshal.go
@@ -426,6 +426,7 @@ type marshalOperation struct {
 	Type  string
 	Begin *string `json:",omitempty"`
 	End   *string `json:",omitempty"`
+	Info  *string `json:".omitempty"`
 }
 
 func newBool(b bool) *bool { return &b }
@@ -468,31 +469,31 @@ func decodeGraph(r io.Reader) (*marshalGraph, error) {
 	return g, nil
 }
 
-// *Annotation structs allow encoding arbitrary information about the graph in
+// *DebugInfo structs allow encoding arbitrary information about the graph in
 // the logs.
-type vertexAnnotation struct {
+type vertexDebugInfo struct {
 	Type   string
 	Vertex *marshalVertex
 	Info   string
 }
 
-func newVertexAnnotation(v Vertex, info string) *vertexAnnotation {
-	return &vertexAnnotation{
-		Type:   "VertexAnnotation",
+func newVertexDebugInfo(v Vertex, info string) *vertexDebugInfo {
+	return &vertexDebugInfo{
+		Type:   "VertexDebugInfo",
 		Vertex: newMarshalVertex(v),
 		Info:   info,
 	}
 }
 
-type edgeAnnotation struct {
+type edgeDebugInfo struct {
 	Type string
 	Edge *marshalEdge
 	Info string
 }
 
-func newEdgeAnnotation(e Edge, info string) *edgeAnnotation {
-	return &edgeAnnotation{
-		Type: "EdgeAnnotation",
+func newEdgeDebugInfo(e Edge, info string) *edgeDebugInfo {
+	return &edgeDebugInfo{
+		Type: "EdgeDebugInfo",
 		Edge: newMarshalEdge(e),
 		Info: info,
 	}
diff --git a/dag/marshal_test.go b/dag/marshal_test.go
index 7c4fd4280..f9628e27a 100644
--- a/dag/marshal_test.go
+++ b/dag/marshal_test.go
@@ -130,7 +130,7 @@ func TestGraphJSON_basicRecord(t *testing.T) {
 }
 
 // Verify that Vertex and Edge annotations appear in the debug output
-func TestGraphJSON_annotations(t *testing.T) {
+func TestGraphJSON_debugInfo(t *testing.T) {
 	var g Graph
 	var buf bytes.Buffer
 	g.SetDebugWriter(&buf)
@@ -140,9 +140,9 @@ func TestGraphJSON_annotations(t *testing.T) {
 	g.Add(3)
 	g.Connect(BasicEdge(1, 2))
 
-	g.AnnotateVertex(2, "2")
-	g.AnnotateVertex(3, "3")
-	g.AnnotateEdge(BasicEdge(1, 2), "1|2")
+	g.DebugVertexInfo(2, "2")
+	g.DebugVertexInfo(3, "3")
+	g.DebugEdgeInfo(BasicEdge(1, 2), "1|2")
 
 	dec := json.NewDecoder(bytes.NewReader(buf.Bytes()))
 
@@ -156,8 +156,8 @@ func TestGraphJSON_annotations(t *testing.T) {
 		}
 
 		switch d.Type {
-		case "VertexAnnotation":
-			va := &vertexAnnotation{}
+		case "VertexDebugInfo":
+			va := &vertexDebugInfo{}
 			err := json.Unmarshal(d.JSON, va)
 			if err != nil {
 				t.Fatal(err)
@@ -177,8 +177,8 @@ func TestGraphJSON_annotations(t *testing.T) {
 			default:
 				t.Fatalf("unexpected annotation: %#v", va)
 			}
-		case "EdgeAnnotation":
-			ea := &edgeAnnotation{}
+		case "EdgeDebugInfo":
+			ea := &edgeDebugInfo{}
 			err := json.Unmarshal(d.JSON, ea)
 			if err != nil {
 				t.Fatal(err)
diff --git a/terraform/graph.go b/terraform/graph.go
index 369f01e4a..e4ff7a710 100644
--- a/terraform/graph.go
+++ b/terraform/graph.go
@@ -294,7 +294,7 @@ func (g *Graph) walk(walker GraphWalker) error {
 			// then callback with the output.
 			log.Printf("[DEBUG] vertex '%s.%s': evaluating", path, dag.VertexName(v))
 
-			g.AnnotateVertex(v, fmt.Sprintf("evaluating %T(%s)", v, path))
+			g.DebugVertexInfo(v, fmt.Sprintf("evaluating %T(%s)", v, path))
 
 			tree = walker.EnterEvalTree(v, tree)
 			output, err := Eval(tree, vertexCtx)
@@ -310,7 +310,7 @@ func (g *Graph) walk(walker GraphWalker) error {
 				path,
 				dag.VertexName(v))
 
-			g.AnnotateVertex(v, fmt.Sprintf("expanding %T(%s)", v, path))
+			g.DebugVertexInfo(v, fmt.Sprintf("expanding %T(%s)", v, path))
 
 			g, err := ev.DynamicExpand(vertexCtx)
 			if err != nil {
@@ -332,7 +332,7 @@ func (g *Graph) walk(walker GraphWalker) error {
 				path,
 				dag.VertexName(v))
 
-			g.AnnotateVertex(v, fmt.Sprintf("subgraph: %T(%s)", v, path))
+			g.DebugVertexInfo(v, fmt.Sprintf("subgraph: %T(%s)", v, path))
 
 			if rerr = sn.Subgraph().(*Graph).walk(walker); rerr != nil {
 				return