Documentation and implementation mismatch for default model in Agent class

[ftnext]

I was confused to understand the default model.

Description

There is a discrepancy between the documentation comment and the actual implementation regarding the default model used by the Agent class when no model is specified.

In src/agents/agent.py, the comment states:

openai-agents-python/src/agents/agent.py

Lines 107 to 112 in 0396052

	model: str | Model | None = None
	"""The model implementation to use when invoking the LLM.
	By default, if not set, the agent will use the default model configured in
	`model_settings.DEFAULT_MODEL`.
	"""

However, src/agents/model_settings.py does not contain a DEFAULT_MODEL constant.

The actual implementation logic uses DEFAULT_MODEL = "gpt-4o" defined in src/agents/models/openai_provider.py, which is used in the get_model method when model_name is None.

openai-agents-python/src/agents/run.py

Lines 933 to 942 in 0396052

	@classmethod
	def _get_model(cls, agent: Agent[Any], run_config: RunConfig) -> Model:
	if isinstance(run_config.model, Model):
	return run_config.model
	elif isinstance(run_config.model, str):
	return run_config.model_provider.get_model(run_config.model)
	elif isinstance(agent.model, Model):
	return agent.model
	return run_config.model_provider.get_model(agent.model)

openai-agents-python/src/agents/models/openai_provider.py

Lines 81 to 83 in 0396052

	def get_model(self, model_name: str | None) -> Model:
	if model_name is None:
	model_name = DEFAULT_MODEL

openai-agents-python/src/agents/models/openai_provider.py

Line 11 in 0396052

DEFAULT_MODEL: str = "gpt-4o"

Suggested Fix

Update the comment in agent.py.

model: str | Model | None = None
"""The model implementation to use when invoking the LLM.

By default, if not set, the agent will use the default model configured in
`openai_provider.DEFAULT_MODEL` (currently "gpt-4o").
"""

[rm-openai]

Makes sense, PR welcome!