diff --git a/docs/index.md b/docs/index.md
index 8845c90..47d3720 100644
--- a/docs/index.md
+++ b/docs/index.md
@@ -41,6 +41,7 @@ We model the LLM workflow as a **Nested Directed Graph**:
 
 - [LLM Wrapper](./llm.md)
 - [Tool](./tool.md)
+- [Visualization](./viz.md)
 - Chunking
 
 > We do not provide built-in implementations. 
diff --git a/docs/viz.md b/docs/viz.md
index d3235bf..956bef1 100644
--- a/docs/viz.md
+++ b/docs/viz.md
@@ -58,9 +58,9 @@ def build_mermaid(start):
             # Handle simple Nodes
             curr_id = get_id(node)
             if isinstance(node, BatchNode):
-                label = f"{curr_id}@{{shape: procs, label: \"{type(node).__name__}\"}}"
+                label = f'{curr_id}@{{shape: procs, label: "{type(node).__name__}"}}'
             else:
-                label = f"{curr_id}@{{label: \"{type(node).__name__}\"}}"
+                label = f'{curr_id}@{{label: "{type(node).__name__}"}}'
 
             if parent_id:
                 lines.append(f"    {label}")