[posthog]

Why

Nothing in the specs says a $feature_flag_called event identifies which flag definition produced the value. feature-flag-called-tracker names $feature_flag_id and $feature_flag_version only in passing, inside the minimal-event allowlist, as "evaluation debug scalars the server/SDK already attaches" — which reads as "whatever the remote response happened to carry". A server SDK evaluating a flag locally therefore had no stated obligation to attach either one.

PostHog/posthog-python#1149 closed that gap. A locally evaluated read now takes id and version from the local flag definition, across get_feature_flag(), feature_enabled(), get_feature_flag_result() and the tracked get_feature_flag_payload() path. evaluate_flags() previously set $feature_flag_id but hardcoded version=None on the belief that local definitions carry no version; they do, so the snapshot record now reads it from the definition.

posthog-go still sets both properties only from evalResult.FlagDetail (remote /flags metadata) in posthog.go, so its locally evaluated events omit them. This records posthog-python's behavior as the winner for that divergence.

What changed

New requirement Flag definition identity on flag-called events in feature-flag-called-tracker:

• $feature_flag_called carries $feature_flag_id and $feature_flag_version for a locally evaluated read as well as a remote one.
• Local values come from the definition that produced the value, read from the same definitions snapshot, so a refresh between evaluation and capture cannot report another revision's identity.
• Each property is omitted when its source does not carry it; a missing version does not suppress the id.
• Applies to every read path that emits the event, and a structured snapshot read records the same values on the locally evaluated flag record.

No public API change, no change to the dedupe contract, and no change to the minimal-event allowlist — both properties were already on it.

Proposed, applied and archived on this branch per AGENTS.md: openspec/changes/archive/2026-11-03-add-local-flag-called-identity/.

Uncertain

• The snapshot-consistency rule ("read the local definition from the same definitions snapshot that produced the value") generalizes an implementation detail of the posthog-python fix. It is the correct behavior under a concurrent definitions refresh, but no other SDK states it today.
• The openspec CLI is not installed in this environment, so openspec validate --specs --strict was not run; the delta was applied and archived by hand following the format of the existing archived changes.

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