Hit all five in one day, so it became a table.
| Response | What actually happened |
|---|---|
200 + code=ERROR | Tried to modify a resource under review. HTTP is 200. |
200 + rows=0 | Filtered on an enum value that doesn't exist. Not an error; an empty result. |
200 + code=SUCCESS + no effect | Partial update silently ignored. 26 minutes later, unchanged. |
200 + code=SUCCESS + warning | A warning attached, but it actually applied. Read the warning as failure and you retry healthy items. |
400 PRECONDITION_FAILED | Simply a path that doesn't exist. Not a precondition violation. |
★ There are at least three axes of success/failure: HTTP status, code in the body, and the actual value on re-fetch. The first two can both pass while the third differs.
Enforcement
def ok(code, resp):
return code == 200 and isinstance(resp, dict) and resp.get("code") != "ERROR"Without it, ~700 items spun for nothing. All rejected, all recorded as success in the progress file.
And this is still not enough. Row 3 in the table passes ok(). After every write, re-fetch the single record and check the real value. If there's a change-history endpoint, that is even more reliable.
The reverse direction: a success that looks like failure
A write's success response carried message as the string "[]". Not an empty array; a truthy string that looks like one. Code that judged errors with if msg: recorded items that had applied correctly as failures. Empty-value representations vary by type: "", [], "[]", {}, null. Judge by content, not by presence.
★ A contaminated failure list invalidates every diagnosis built on it. Those "failures" became the evidence for a wrong root cause; the real culprit was elsewhere. When one verdict function is wrong, throw away not just the batch result but every conclusion drawn from it.
A sixth shape: the rejected list went unread
A tracking-registration API returns accepted and rejected as separate lists. The wrapper ignored the rejected list and recorded every item as registered in the local DB. Items rejected because carrier auto-detection failed sat there untrackable. Count accepted, and alert when it is 0.
★ And accepted isn't the end either. Registration can succeed while tracking returns not-found. "Accepted" means registered, not tracked. Success has one more layer.