update guide

docs/guide.md

@@ -53,6 +53,8 @@ Agentic Coding should be a collaboration between Human System Design and Agent I
       - *Input*: `str`
       - *Output*: a vector of 3072 floats
       - *Necessity:* Used by the second node to embed text
+    - > **Sometimes, design Utilies before Flow:**  For example, for an LLM project to automate a legacy system, the bottleneck will likely be the available interface to that system. Start by designing the hardest utilities for interfacing, and then build the flow around them.
+      {: .best-practice }
 
 4. **Node Design**: Plan how each node will read and write data, and use utility functions.
    - Start with the shared data design

docs/index.md

@@ -49,7 +49,7 @@ From there, it’s easy to implement popular design patterns:
 
 ## Utility Function
 
-We **do not** provide built-in utilities. Instead, we offer *examples*—please *implement your own*.
+We **do not** provide built-in utilities. Instead, we offer *examples*—please *implement your own*:
 
 - [LLM Wrapper](./utility_function/llm.md)
 - [Viz and Debug](./utility_function/viz.md)