Chapter Six · Review
Reading the Diff
The read stage of the loop. The agent has finished step three of the refund change and reports success; this chapter is what to do with what came back. Five topics treat the diff as the product, read it in an order that finds the worst problem first, put five questions to it, separate the agent's explanations from evidence, and end on rejecting, narrowing or redirecting.
The task was step three from Chapter 5: the refund window becomes 12 hours, and the tests that encoded 24 move with it. The approved plan named two files and fewer than 20 lines. The agent reports "Changed the refund window to 12 hours and updated the tests accordingly", and the refunds tests are green.
The diff behind that sentence is local canon for Chapters 6 to 9, and this book calls it the refund diff: six files, 128 lines added and 14 removed. It contains the asked-for change and a correct update to the 23-hour test. It also contains a boundary flip that refuses a refund at exactly 12 hours, a deadline computed on the server's clock instead of the gym's with a test edited to agree, a pack refund rounded up a cent, a configuration object so each gym can set its own window, and a typo fixed in a comment. The cancellation email and the schedule page still say 24 hours. Every page of this chapter reads the same diff, and Chapters 7 to 9 come back to it.