docs/plans/write-commands-reverse-engineering.md (425 lines):
Plan for adding WriteValueAsync (AddS2 stream values), EnsureTags2 for
analog/discrete/string tags, and DelT for sandbox cleanup. Hard safety
rules center on a dedicated sandbox tag gated by env var, time-bounded
writes, SQL ground-truth verification per session, explicit rollback.
Five-step RE workflow mirrors the read/event decode (static IL discovery
-> instrument-wcf-writemessage capture -> instrument-wcf-readmessage
capture -> byte/IL alignment -> managed serializer + golden-byte tests).
Risks call out auth-chain unknowns, parameter-name-mismatch class,
silent-success failure modes, History-vs-Storage service question.
docs/plans/store-forward-cache-reverse-engineering.md (501 lines):
Plan for replacing the synthesized GetStoreForwardStatusAsync with a
real implementation. Architecture investigation already partially
answered via IL inspection during planning: ArchestrA.HistorianAccess.
GetStoreForwardStatus (token 0x06006187) reads an in-process C struct
via calli to mdas_GetStorageStatus, kept current by server-pushed WCF
callbacks (IStatusServiceContract2.SetStoreForwardEvent). CSFConnection.
GetSFPipeName indicates a separate Named Pipe sidecar exists when SF
is configured. Five parallelizable discovery workstreams, six concrete
RE steps with cited tokens, eight risks, eight success criteria.
Both plans deliberately produce no code changes and no captures. They
exist so the next implementer can start with full context.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Decoded the GetTagInfoFromName response shape across multiple tag types via
captured raw bytes (sanitized decoder script in scripts/decode-taginfo-bytes.py):
- Compact-ASCII string slot count varies by tag origin: 2 strings for
MDAS-routed external tags (TagName + MetadataProvider), 4 strings for local
Sys tags (TagName + Description + ItemName + CreatedBy). Parser now walks
strings dynamically until the next byte isn't the 0x09 marker.
- Trailing region after the 4-byte fixed block holds (for analog tags) two
doubles for MinEU/MaxEU plus an optional EngineeringUnit compact ASCII
string and other fields whose exact positions vary. Parser uses a tolerant
scan: tries each 8-byte alignment 0..7, picks the first sane (Min ≤ Max,
finite, not all-zeros, |x| ≤ 1e15) double pair as MinEU/MaxEU, and finds
the first plausible compact ASCII string (1..32 ASCII bytes, not numeric)
as EngineeringUnit.
HistorianTagMetadata.Description / EngineeringUnit / MinRaw / MaxRaw nullable
slots already existed; they're now populated. Live verification: SysTimeSec
returns Description="System Time : Seconds", MaxRaw=59.0, EngineeringUnit
="Seconds".
Tests: 109 → 114 (+4 synthetic-fixture parser tests + 1 live integration
test for the populated analog metadata path). Bulk descriptor probe helper
(GetTagInfoRawBytesForProbe) added for future layout work; raw bytes never
committed because they contain CreatedBy DOMAIN\user identity.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Full read-only SDK (src/AVEVA.Historian.Client) implementing the CLAUDE.md required
surface against AVEVA Historian's binary WCF protocol — no native AVEVA runtime
dependency. All operations live-verified against a local Historian:
- ProbeAsync, ReadRawAsync, ReadAggregateAsync, ReadAtTimeAsync, ReadEventsAsync
- BrowseTagNamesAsync, GetTagMetadataAsync (17 native data-type codes mapped)
- GetConnectionStatusAsync, GetStoreForwardStatusAsync, GetSystemParameterAsync
- 108/108 unit + integration tests pass
Includes the reverse-engineering toolkit (tools/AVEVA.Historian.ReverseEngineering)
used to decode the protocol: WCF probes, IL inspection via dnlib, and IL-rewrite
instrumentation (instrument-wcf-{write,read}message etc.) plus the .NET Framework
trace harness (tools/AVEVA.Historian.NativeTraceHarness) for parity testing.
Sanitized handoff evidence under docs/reverse-engineering/. Native AVEVA binaries
(current/, aveva-install-x64/, aveva-install-x86/) are gitignored — fetch separately
from the AVEVA installer.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
dohertj2