What is the difference between an agent's system prompt instructions and a Prompt Template, and how are they configured?

1. Agent Instructions (System Prompt): Configured directly in Agent Builder as the agent's role definition and behavioural guidelines — e.g., "You are Aria, a friendly customer service agent for Acme Corp. Always respond in a professional tone. Never discuss competitor products. If unsure, escalate." These instructions are prepended to every LLM call as the system prompt and define the agent's persona, constraints, and general behaviour across all Topics. They are managed in Agent Builder's "Instructions" panel.
2. Prompt Templates: Reusable, versioned templates for specific generation tasks — record summarisation, email drafting, RAG grounding. They are invoked as discrete Actions within a topic, and can merge dynamic Salesforce data via template merge syntax. They have their own test/preview tooling, version history, and can be reused across multiple agents and topics.
3. Relationship: The system instructions set the agent's overall behaviour context; Prompt Templates generate specific content for specific tasks. A template executes within the context established by the system instructions — the agent's persona applies to template-generated responses. Both are separate metadata types managed independently, enabling the agent's persona to be updated without touching templates, and templates to be reused across different agents with different personas.