Chore: suggest to use either static or dynamic routing for a node (#3758)

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---------

Co-authored-by: open-swe[bot] <open-swe@users.noreply.github.com>

Author: longquanzheng

src/oss/langgraph/graph-api.mdx

@@ -873,6 +873,10 @@ Edges define how the logic is routed and how the graph decides to stop. This is
 
 A node can have multiple outgoing edges. If a node has multiple outgoing edges, **all** of those destination nodes will be executed in parallel as a part of the next superstep.
 
+<Warning>
+For each node, choose one routing mechanism: use normal edges for static routing, or use conditional edges / @[`Command`] for dynamic routing. Do not mix normal edges and dynamic routing from the same node, because both paths can execute and make graph behavior harder to reason about.
+</Warning>
+
 ### Normal edges
 
 :::python
@@ -1133,7 +1137,7 @@ builder.addNode("myNode", myNode, {
 
 <Warning>
 
-@[`Command`] only adds dynamic edges—static edges defined with `add_edge` / `addEdge` still execute. For example, if `node_a` returns `Command(goto="my_other_node")` and you also have `graph.add_edge("node_a", "node_b")`, both `node_b` and `my_other_node` will run.
+@[`Command`] only adds dynamic edges—static edges defined with `add_edge` / `addEdge` still execute. For example, if `node_a` returns `Command(goto="my_other_node")` and you also have `graph.add_edge("node_a", "node_b")`, both `node_b` and `my_other_node` will run. For each node, use either @[`Command`] or static edges to route to the next nodes, not both.
 
 </Warning>
 
@@ -1289,7 +1293,7 @@ You can return @[`Command`] from tools to update graph state and control flow. U
 
 <Warning>
 
-When used inside tools, `goto` adds a dynamic edge—any static edges already defined on the node that called the tool will still execute.
+When used inside tools, `goto` adds a dynamic edge—any static edges already defined on the node that called the tool will still execute. For each node, use either tool-driven dynamic routing or static edges to route to the next nodes, not both.
 
 </Warning>