What model selection options are available in Agentforce and what is the Model Builder?

Agentforce provides flexible LLM selection:

1. Default Einstein LLM: Salesforce's hosted, pre-configured LLM (powered by partnerships with providers like Anthropic and OpenAI) available out of the box. It is the simplest option — no configuration required, and all Einstein Trust Layer protections apply automatically.
2. BYOM (Bring Your Own Model) via Model Builder: Organisations can connect external LLMs (e.g., their own fine-tuned model hosted on AWS, Azure, or GCP) through the Model Builder configuration in Setup. This allows use of proprietary models, domain-specific fine-tuned models, or models required for data sovereignty reasons.
3. Model Builder: The configuration surface in Salesforce Setup where custom model connections are defined — specifying the endpoint URL, authentication credentials, and request/response schema mapping to Salesforce's standard LLM interface. Once configured, a custom model can be selected at the Prompt Template or Agent level.
4. Model selection per template: Different Prompt Templates can use different models — e.g., a summarisation template might use a lighter model for cost efficiency while a complex reasoning task uses a larger model.