Phase 1 of docs/plans/write-commands-reverse-engineering.md is purely
discovery — static IL inspection, public-API enumeration, scope
elimination — and produces no DB writes. Phase 2 requires extending
NativeTraceHarness with a write scenario AND explicit operator approval
per the plan's safety rule §1, so it is deferred to a separate session.
Phase 1 findings recorded inline in the plan's status header:
1. §3.4 ModifyData/DeleteData eliminated — no managed wrapper exists.
`methods` returns zero hits for EditValue, ModifyValue, EditData,
DeleteData, ModifyData, OverwriteData. Per the plan's own §3.4
disposition rule, this op is REST/SMC-only.
2. §4.a native serializer tokens identified for Phase 2:
Public managed-wrapper write API in ArchestrA.HistorianAccess:
- AddTag (0x0600619A)
- AddStreamedValue × 3 overloads (0x0600618C/D/E)
- AddNonStreamedValue × 2 overloads (0x0600618F/90)
- DeleteTags (0x060061A4)
- AddRevisionValuesBegin / AddRevisionValue / AddRevisionValuesEnd
/ AddRevisionValues (0x06006175-77, 0x0600617F)
— covers the bulk-modify use case the eliminated ModifyData would
have served. Worth folding into Phase 2 scope.
Native serializers:
- CTagUtil.ConvertTagMetadataToHistorianTag (0x060055CE) — 412 IL
instructions; builds CTagMetadata for analog/discrete/string.
Calls every CTagMetadata accessor we'd need to surface
(Min/MaxRaw, Min/MaxEU, Unit, Message0/1, MaxLength,
IntegralDivisor, DefaultTagRate, RolloverValue) plus all the
CDataType predicates already decoded.
- CHistoryConnectionWCF.AddStreamValuesToHistorian (0x0600404C)
— confirms the on-wire shape matches our existing
IHistoryServiceContract2.AddStreamValues2 declaration.
3. Chicken-and-egg resolved: the first §3.1 EnsT2 test creates the
sandbox tag itself, so no SMC step is needed.
4. Open question §8.6 answered — the wrapper exposes both
AddStreamedValue and AddNonStreamedValue, so the SDK should
eventually surface both real-time and backfill write modes.
Phase 2 next steps recorded inline in the plan as a 5-item executable
checklist (extend harness with --scenario write, capture, decode
EnsT2(analog) + AddS2 bytes, implement public surface, gated live
tests).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
dohertj2
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