docs: clarify agent prompt append behavior

Author: jonathanpopham

cli/quickstart.mdx

@@ -30,6 +30,8 @@ supermodel skill >> CLAUDE.md
 # or AGENTS.md, .cursorrules, etc.
 ```
 
+Use `>>` to append to existing instructions instead of replacing them. If the Supermodel block is already present, skip this step or remove the old block before running it again.
+
 The prompt explains the naming convention (`Foo.py` → `Foo.graph.py`) and tells your agent to read the graph file before the source file.
 
 ## 3. Use the live graph

index.mdx

@@ -43,6 +43,8 @@ supermodel skill >> CLAUDE.md
 # or AGENTS.md, .cursorrules, etc.
 ```
 
+Use `>>` to append to existing instructions instead of replacing them. If the Supermodel block is already present, skip this step or remove the old block before running it again.
+
 The prompt explains the naming convention (`Foo.py` → `Foo.graph.py`), the three sections inside each sidecar (`[deps]`, `[calls]`, `[impact]`), and tells the agent to read the sidecar before the source file.
 
 ### 4. What you get