## TL;DR
Read the region from the feature group metadata and send the lookup to that region, removing any default region the agent assumed, because the group lives in a different region than the one queried and a lookup in the wrong region reports the group as missing. Start with the feature group metadata for its actual region, beside the region the agent queried, work on one affected call, record, or run first, and prove the fix there before running the full set. Most cases clear once the cause named in step 2 is corrected at its source rather than retried unchanged.

```text
agent hallucinating online store region for feature group caused lookup failure error
```

## Use this when
- You see this exact message or symptom: agent hallucinating online store region for feature group caused lookup failure error
- One run, record, call, or object is affected and you can name it
- A retry without changing anything reproduces the same result

## Not for this skill when
- The system fails with a different message and none of the signals here appear
- Nothing has failed yet and you are doing first time setup or general planning
- Every service from this vendor is down for all users, which is a vendor outage to wait out first

## Steps
1. Reproduce the failure once using the feature group metadata for its actual region, beside the region the agent queried, and record the time, the workspace or account, and the one item it names. Verify: you have one failing item identified, not a similar older failure
2. Inspect the region recorded on the group, the region in the failing lookup, and where the assumed region came from in the agent config. Verify: you can point to the specific value, field, segment, or state that does not match what this operation needs
3. Apply the fix at that source: Read the region from the feature group metadata and send the lookup to that region, removing any default region the agent assumed, because the group lives in a different region than the one queried and a lookup in the wrong region reports the group as missing. Verify: the corrected value or setting is visible in the system itself, not only in a local file or the agent notes
4. Re-run the original operation on the single affected item first. Verify: that one item completes with no trace of the failure described above, and the online and offline values for that entity agree
5. Check the downstream result a user or the next job would see, comparing it against the source for the same item. Verify: the downstream result agrees with the source in content and in timing
6. Repeat for the full set, watch the first few items in the same log you started from, and write the root cause and the changed setting into the run notes. Verify: the full run finishes, the notes name the failure and the fix, and no earlier item regressed

## Variant phrasings
### agent hallucinating online store region for feature group caused lookup failure error
The subject-first phrasing of the same failure. The fix is the same, start at step 1 and confirm the item the log or record names.
### Tool-first phrasing of this failure
The phrasing searchers use once they know which system raised it. It is the same underlying problem, not a separate bug.
### Why does this keep happening after a retry
The repeat-occurrence phrasing. A retry without the step 2 and step 3 checks almost always reproduces it, because the cause sits in the input, setting, or record state, not in the attempt.

Compatibility: Hopsworks, SageMaker, and Vertex feature groups across regions, agent lookups.

## Why it happens
Agents fill a missing region with the project default, and multi region stores make that guess wrong for a minority of groups, the ones created for a specific market or compliance need.

## Provenance

Resolved from the public thread: https://vectle.com/posts/pst_qOIQiFuSq1bjxW5R6KzsYA