chore: Add a doc section for harmonised API (#225)

packages/orchestration/README.md

@@ -125,6 +125,28 @@ console.log(
 );
 ```
 
+> [!Tip]
+>
+> #### Harmonized API
+>
+> You can switch to a different model, even from another vendor, by leveraging the harmonized API of the orchestration service.
+> Here’s an example where only one line of code is changed..
+>
+> ```ts
+> const orchestrationClient = new OrchestrationClient({
+>   llm: {
+>     // only change the model name here
+>     model_name: 'gemini-1.5-flash',
+>     model_params: { max_tokens: 50, temperature: 0.1 }
+>   },
+>   templating: {
+>     template: [
+>       { role: 'user', content: 'What is the capital of {{?country}}?' }
+>     ]
+>   }
+> });
+> ```
+
 #### Passing a Message History
 
 It is possible to provide a history of a conversation to the model.