Add litellm support

Signed-off-by: Víctor Mayoral Vilches <v.mayoralv@gmail.com>

config.yaml

@@ -0,0 +1,23 @@
+model_list:
+  - model_name: claude-3-7
+    litellm_params: 
+      model: claude-3-7-sonnet-20250219
+      api_key: "os.environ/ANTHROPIC_API_KEY" # does os.getenv("ANTHROPIC_API_KEY")
+      base_url: 'https://api.anthropic.com'
+  - model_name: gpt-4o
+    litellm_params:
+      model: gpt-4o
+      api_key: "os.environ/OPENAI_API_KEY"
+      api_base: https://api.openai.com/v1
+  - model_name: qwen2.5:14b
+    litellm_params:
+      model: ollama/qwen2.5:14b
+      api_base: http://localhost:8000
+      api_key: "os.environ/OLLAMA"
+
+litellm_settings: # module level litellm settings - https://github.com/BerriAI/litellm/blob/main/litellm/__init__.py
+  drop_params: True
+  # set_verbose: True
+
+general_settings: 
+  port: 4000

examples/agent_patterns/claude.py

@@ -0,0 +1,25 @@
+from openai import AsyncOpenAI
+from agents import OpenAIChatCompletionsModel,Agent,Runner
+from agents.model_settings import ModelSettings
+from agents import set_default_openai_client, set_tracing_disabled
+import os
+
+external_client = AsyncOpenAI(
+    base_url = 'https://api.anthropic.com/v1',
+    api_key=os.getenv('ANTHROPIC_API_KEY', None)
+)
+
+set_default_openai_client(external_client)
+set_tracing_disabled(True)
+
+agent = Agent(
+    name="Assistant", 
+    instructions="You are a helpful assistant",
+    model=OpenAIChatCompletionsModel(
+        model="claude-3-5-sonnet-20240620",
+        openai_client=external_client,
+    )
+)
+
+result = Runner.run_sync(agent, "Write a haiku about recursion in programming.")
+print(result.final_output)