RUN_FROZEN
- HTTP status
- 409
- Details payload
{ frozenFields: string[], currentRunId: string, attemptedChange: string, recommendedAction: RecommendedAction }
Cause
The edit touches a field that a running Run freezes. Changing it mid-flight would rebucket Entities that were already measured, so the write is refused whole.
Fix
details.frozenFields names exactly what is immutable and details.recommendedAction names the way out. An assignment field (salt, allocation, variantSet, targetingRules, targetingSegmentId, experiment.targetingKey, activationMetricId) returns CREATE_NEW_RUN, because a draft Run holds that field and the change applies cleanly there. An App-level or Flag Configuration field (flagConfig.*, variant.value) returns END_RUNNING_RUN_FIRST, because no draft Run has a destination for it.