373 个测试全绿，幂等性 bug 却让我多付了一次钱

A LangGraph agent with the reliability layer that decides whether it can ship.

Building the graph is the easy half. The half that decides whether it goes live is everything around it: what happens when the process dies between two nodes whether the refund gets paid twice on the way back up, whether an approval somebody gave on Tuesday can authorise a different action on Thursday, and whether anyone can say out loud how often the router is right.

This repo answers those four questions with code and with numbers, on a support desk for a fictional product. All data is synthetic.

The report this repo exists to produce

Real output from python -m langgraph_production.evaluation on this repository, not an illustration:

========================================================================
SUPPORT GRAPH EVALUATION
========================================================================
  fixtures      answer 13, escalate 15, tool 23  (total 51)
ROUTING
  accuracy      46/51 = 90.2%
  macro F1      0.907
  tool choice   22/23 correct (95.7%) on