Agentic tool-calling protocol for real-time, per-request system access

How a caller — an LLM-driven parser or a program — invokes a live action or read against an external system at request time, as distinct from a scheduled or batch ingestion pipeline. Covers protocol choice (MCP, direct REST/SOAP, a vendor-proprietary tool-calling format), schema declaration for each callable tool, and how failure/timeout is signalled back to the caller.