diff --git a/scripts/canary-rollout.sh b/scripts/canary-rollout.sh
index 68b40c4b2..5ed2516ba 100755
--- a/scripts/canary-rollout.sh
+++ b/scripts/canary-rollout.sh
@@ -1017,6 +1017,14 @@ _registered_reusables_for_host() {
   _jq -r --arg h "$1" '[.agents[]? | select(.host==$h) | .reusable // empty] | unique | .[]'
 }
 
+# _unmanaged_reusables_for_host <host> — reusable paths on <host> INTENTIONALLY out of the
+# ring-gate model, recorded in the `unmanaged` block (#651): single-hop channel reusables,
+# frozen-major `@vN` infra, or dispatch-only workflows. drift excludes these so its
+# "unregistered" signal only flags reusables that genuinely still need onboarding.
+_unmanaged_reusables_for_host() {
+  _jq -r --arg h "$1" '[.unmanaged[]? | select(.host==$h) | .reusable // empty] | unique | .[]'
+}
+
 # _agents_for_reusable <host> <path> — the registry agent name(s) whose (host,reusable)
 # match, joined by ", " (for the missing-file finding message).
 _agents_for_reusable() {
@@ -1061,7 +1069,7 @@ cmd_drift() {
   while IFS= read -r host; do
     [ -z "$host" ] && continue
     echo "──────── host: $host ────────"
-    local present registered unregistered missing p agents
+    local present registered unmanaged_r unregistered missing p agents
     if ! present="$(_gh_list_reusables "$host")"; then
       # Could not read the host's workflows dir — skip it rather than false-flag every
       # registered reusable as missing-file. Read-only + best-effort: a warning, not a failure.
@@ -1069,15 +1077,19 @@ cmd_drift() {
       continue
     fi
     registered="$(_registered_reusables_for_host "$host")"
-    local reg_arr=() pres_arr=() reg_str="" pres_str=""
+    unmanaged_r="$(_unmanaged_reusables_for_host "$host")"
+    local reg_arr=() pres_arr=() um_arr=() reg_str="" pres_str="" um_str=""
     if [ -n "$registered" ]; then mapfile -t reg_arr <<< "$registered"; fi
     if [ -n "$present" ]; then mapfile -t pres_arr <<< "$present"; fi
+    if [ -n "$unmanaged_r" ]; then mapfile -t um_arr <<< "$unmanaged_r"; fi
     [ "${#reg_arr[@]}" -gt 0 ] && reg_str=" ${reg_arr[*]}"
     [ "${#pres_arr[@]}" -gt 0 ] && pres_str=" ${pres_arr[*]}"
+    [ "${#um_arr[@]}" -gt 0 ] && um_str=" ${um_arr[*]}"
     echo "  registered reusables (${#reg_arr[@]}):$reg_str"
     echo "  present *-reusable.yml (${#pres_arr[@]}):$pres_str"
-    # unregistered = present on the host but not in the registry.
-    unregistered="$(set_difference "$present" "$registered")"
+    [ "${#um_arr[@]}" -gt 0 ] && echo "  unmanaged (intentional, out of ring gate) (${#um_arr[@]}):$um_str"
+    # unregistered = present on the host, minus registered agents AND intentionally-unmanaged (#651).
+    unregistered="$(set_difference "$(set_difference "$present" "$registered")" "$unmanaged_r")"
     while IFS= read -r p; do
       [ -z "$p" ] && continue
       echo "::warning::DRIFT[unregistered] $host: $p present on host but absent from canary-rings.json (no cut/soak/gate/dashboard until registered)"
diff --git a/standards/canary-rings.json b/standards/canary-rings.json
index 1d3ad8b54..b29783f72 100644
--- a/standards/canary-rings.json
+++ b/standards/canary-rings.json
@@ -593,5 +593,22 @@
         }
       }
     }
+  },
+  "unmanaged": {
+    "add-to-project": {
+      "host": "petry-projects/.github",
+      "reusable": ".github/workflows/add-to-project-reusable.yml",
+      "reason": "Single-hop @add-to-project/stable channel (5 consumers); low-risk project-automation plumbing, intentionally out of the full ring gate (#651)."
+    },
+    "claude-code": {
+      "host": "petry-projects/.github",
+      "reusable": ".github/workflows/claude-code-reusable.yml",
+      "reason": "Frozen-major @v2 base wrapper \u2014 not a canary-promoted agent."
+    },
+    "pr-auto-review": {
+      "host": "petry-projects/.github",
+      "reusable": ".github/workflows/pr-auto-review-reusable.yml",
+      "reason": "Frozen-major @v2 review-dispatcher infra \u2014 not a canary-promoted agent."
+    }
   }
 }
diff --git a/tests/canary_rollout.bats b/tests/canary_rollout.bats
index 798f92595..b09a2e668 100644
--- a/tests/canary_rollout.bats
+++ b/tests/canary_rollout.bats
@@ -1094,6 +1094,29 @@ _drift_rings_one_agent() {
   [[ "$output" != *"ci.yml present on host"* ]]
 }
 
+@test "orchestrator: drift excludes an intentionally-unmanaged reusable (#651)" {
+  # Registry: dev-lead agent + an `unmanaged` entry for foo-reusable.yml on .github-private.
+  DRIFT_RINGS="$BATS_TEST_TMPDIR/drift-rings-um.json"
+  jq '{version, description, org_infra_repos, member_tokens,
+       agents: {"dev-lead": .agents["dev-lead"]},
+       unmanaged: {"foo": {"host":"petry-projects/.github-private","reusable":".github/workflows/foo-reusable.yml","reason":"single-hop infra (#651)"}}}' \
+    "$RINGS" > "$DRIFT_RINGS"
+  # host has dev-lead (registered) + foo (unmanaged) + bar (genuinely unregistered)
+  _drift_stub '[
+    {"type":"file","name":"dev-lead-reusable.yml","path":".github/workflows/dev-lead-reusable.yml"},
+    {"type":"file","name":"foo-reusable.yml","path":".github/workflows/foo-reusable.yml"},
+    {"type":"file","name":"bar-reusable.yml","path":".github/workflows/bar-reusable.yml"}
+  ]' '[]'
+  run env CANARY_RINGS="$DRIFT_RINGS" bash "$ORCH" drift
+  [ "$status" -eq 0 ]
+  # foo is reported as unmanaged, NOT flagged as unregistered drift
+  [[ "$output" == *"unmanaged (intentional"* ]]
+  [[ "$output" != *"DRIFT[unregistered] petry-projects/.github-private: .github/workflows/foo-reusable.yml"* ]]
+  # bar (neither registered nor unmanaged) IS still flagged, and it's the ONLY one
+  [[ "$output" == *"DRIFT[unregistered] petry-projects/.github-private: .github/workflows/bar-reusable.yml"* ]]
+  [[ "$output" == *"1 unregistered"* ]]
+}
+
 @test "orchestrator: drift flags a registry entry whose reusable file no longer exists on the host (missing-file)" {
   # Registry has 'ghost' pointing at a reusable that is NOT present on the host.
   DRIFT_RINGS="$BATS_TEST_TMPDIR/drift-ghost.json"