Choose 1 option.

The AgentForce API Integration Guide defines the Agent API as the framework that enables external web or mobile applications to communicate directly with Salesforce-hosted agents. This API supports message exchange, session management, and context persistence — allowing developers to build custom chat interfaces while maintaining secure, real-time connectivity with the AgentForce reasoning engine.

Option A (A2A) is for inter-agent collaboration within Salesforce, not for external web integration. Option B (MCP) — Model Context Protocol — is used for context sharing between models and tools, not for front-end integration.

Therefore, the correct framework for enabling communication between a custom website chat interface and an AgentForce agent is Option C – Agent API, as it provides the structured interface for external client applications.