docs: Update "model" inheritance for agents (#4894)

Co-authored-by: Aiden Cline <[email protected]>

packages/web/src/content/docs/agents.mdx

@@ -315,7 +315,12 @@ This path is relative to where the config file is located. So this works for bot
 
 ### Model
 
-Use the `model` config to override the default model for this agent. Useful for using different models optimized for different tasks. For example, a faster model for planning, a more capable model for implementation.
+Use the `model` config to override the model for this agent. Useful for using different models optimized for different tasks. For example, a faster model for planning, a more capable model for implementation.
+
+:::tip
+If you don’t specify a model, primary agents use the [model globally configured](/docs/config#models) while subagents will use the model of the primary agent that invoked the subagent.
+:::
+
 
 ```json title="opencode.json"
 {