diff --git a/.gitignore b/.gitignore
index 93a15a4b..d0accbef 100644
--- a/.gitignore
+++ b/.gitignore
@@ -51,3 +51,6 @@ src/Server/ZB.MOM.WW.OtOpcUa.Host/pki/
 
 # Documentation audit scratch dir (untracked worktree)
 .docs-audit/
+
+# Vendor binaries — never commit (license risk; see R2-12/U-5)
+lib/
diff --git a/archreview/plans/R2-12-repo-hygiene-plan.md.tasks.json b/archreview/plans/R2-12-repo-hygiene-plan.md.tasks.json
index f0e7f48a..0384fe87 100644
--- a/archreview/plans/R2-12-repo-hygiene-plan.md.tasks.json
+++ b/archreview/plans/R2-12-repo-hygiene-plan.md.tasks.json
@@ -1,8 +1,8 @@
 {
   "planPath": "archreview/plans/R2-12-repo-hygiene-plan.md",
   "tasks": [
-    { "id": 0,  "subject": "T1: U-5 proof — zero references to the 7 lib/ DLLs (grep csproj/props/targets/slnx + no HintPath) + build", "status": "pending", "blockedBy": [] },
-    { "id": 1,  "subject": "T2: U-5 — git rm -r lib/ + .gitignore lib/ guard + rebuild (Commit 1; MAINTAINER SIGN-OFF)", "status": "pending", "blockedBy": [0] },
+    { "id": 0,  "subject": "T1: U-5 proof — zero references to the 7 lib/ DLLs (grep csproj/props/targets/slnx + no HintPath) + build", "status": "completed", "blockedBy": [] },
+    { "id": 1,  "subject": "T2: U-5 — git rm -r lib/ + .gitignore lib/ guard + rebuild (Commit 1; MAINTAINER SIGN-OFF)", "status": "completed", "blockedBy": [0] },
     { "id": 2,  "subject": "T3a: U-6 proof — husk dirs untracked (git ls-files = 0) + absent from slnx", "status": "pending", "blockedBy": [] },
     { "id": 3,  "subject": "T3b: U-6 — rm -rf the 5 Driver.Historian.Wonderware* husk dirs (disk-only, no commit)", "status": "pending", "blockedBy": [2] },
     { "id": 4,  "subject": "T5a: U-4 proof — 5 planning files tracked; re-read looseends.md; present per-file table for sign-off", "status": "pending", "blockedBy": [] },
diff --git a/lib/ArchestrA.CloudHistorian.Contract.dll b/lib/ArchestrA.CloudHistorian.Contract.dll
deleted file mode 100644
index 2ea9eccf..00000000
Binary files a/lib/ArchestrA.CloudHistorian.Contract.dll and /dev/null differ
diff --git a/lib/ArchestrA.MXAccess.dll b/lib/ArchestrA.MXAccess.dll
deleted file mode 100644
index c2da57e4..00000000
Binary files a/lib/ArchestrA.MXAccess.dll and /dev/null differ
diff --git a/lib/Historian.CBE.dll b/lib/Historian.CBE.dll
deleted file mode 100644
index 0dc15137..00000000
Binary files a/lib/Historian.CBE.dll and /dev/null differ
diff --git a/lib/Historian.DPAPI.dll b/lib/Historian.DPAPI.dll
deleted file mode 100644
index 5e4777fa..00000000
Binary files a/lib/Historian.DPAPI.dll and /dev/null differ
diff --git a/lib/aahClient.dll b/lib/aahClient.dll
deleted file mode 100644
index 3b61fe18..00000000
Binary files a/lib/aahClient.dll and /dev/null differ
diff --git a/lib/aahClientCommon.dll b/lib/aahClientCommon.dll
deleted file mode 100644
index 567f6dd0..00000000
Binary files a/lib/aahClientCommon.dll and /dev/null differ
diff --git a/lib/aahClientManaged.dll b/lib/aahClientManaged.dll
deleted file mode 100644
index 12337e99..00000000
Binary files a/lib/aahClientManaged.dll and /dev/null differ