Prototype an AI agent that executes a multi-step workflow, document processing, data enrichment, automated research, or decision routing, to measure the actual reliability, accuracy, and error rate before investing in the production infrastructure, monitoring, and human-escalation workflows that a production agent requires. PoC methodology for AI agents: define the workflow as a sequence of steps with a clear expected output per step and a success criterion for the complete workflow; implement the agent using LangChain/LangGraph or a thin custom ReAct loop (the choice informed by the workflow complexity, LangGraph for branching/looping workflows, a custom loop for strictly linear workflows); define the tool set (web search, database query, file read, API call, structured data extraction) with typed interfaces and error handling; run the agent against 30--50 representative real-world workflow inputs from your actual data. Evaluation dimensions: task completion rate (percentage of inputs where the agent produces a complete, valid output without error or stall); step accuracy (percentage of individual tool calls that return the expected result, distinguishing between the agent reasoning correctly but the tool failing vs the agent making an incorrect tool call); error analysis (classification of failure modes: tool call failure, reasoning error, loop/stall, hallucinated intermediate step); latency measurement (total elapsed time per workflow from input to output, and the distribution across 50 runs). Reliability vs autonomy trade-off: the PoC establishes where the agent is reliable enough to be fully autonomous, where it needs human review for specific step types, and where the overall task is not suitable for autonomous agent execution with your current data and tooling, giving you an evidence-based architecture decision for the full build.