diff --git a/.github/workflows/e2e-staging-external.yml b/.github/workflows/e2e-staging-external.yml
new file mode 100644
index 00000000..787c3169
--- /dev/null
+++ b/.github/workflows/e2e-staging-external.yml
@@ -0,0 +1,164 @@
+name: E2E Staging External Runtime
+
+# Regression for the four/five workspaces.status=awaiting_agent transitions
+# that silently failed in production for five days before migration 046
+# extended the workspace_status enum (see
+# workspace-server/migrations/046_workspace_status_awaiting_agent.up.sql).
+#
+# Why this is its own workflow (not folded into e2e-staging-saas.yml):
+#   - The full-saas harness defaults to runtime=hermes, never exercises
+#     external-runtime. Adding an `external` parameter to that script
+#     would force every push to staging through both lifecycles in
+#     series, doubling the EC2 cold-start budget.
+#   - The external lifecycle has unique timing (REMOTE_LIVENESS_STALE_AFTER
+#     window, 90s default + sweep interval), which we wait through
+#     deliberately. Folding it into hermes would make the long path
+#     even longer.
+#   - It can run in parallel with the hermes E2E since both create
+#     fresh tenant orgs with distinct slug prefixes (`e2e-ext-...` vs
+#     `e2e-...`).
+#
+# Triggers:
+#   - Push to staging when any source affecting external runtime,
+#     hibernation, or the migration set changes.
+#   - PR review for the same set.
+#   - Manual workflow_dispatch.
+#   - Daily cron at 07:30 UTC (catches drift on quiet days; staggered
+#     30 min after e2e-staging-saas.yml's 07:00 UTC cron).
+#
+# Concurrency: serialized so two staging pushes don't fight for the
+# same EC2 quota window. cancel-in-progress=false so a half-rolled
+# tenant always finishes its teardown.
+
+on:
+  push:
+    branches: [staging, main]
+    paths:
+      - 'workspace-server/internal/handlers/workspace.go'
+      - 'workspace-server/internal/handlers/registry.go'
+      - 'workspace-server/internal/handlers/workspace_restart.go'
+      - 'workspace-server/internal/registry/healthsweep.go'
+      - 'workspace-server/internal/registry/liveness.go'
+      - 'workspace-server/migrations/**'
+      - 'workspace-server/internal/db/workspace_status_enum_drift_test.go'
+      - 'tests/e2e/test_staging_external_runtime.sh'
+      - '.github/workflows/e2e-staging-external.yml'
+  pull_request:
+    branches: [staging, main]
+    paths:
+      - 'workspace-server/internal/handlers/workspace.go'
+      - 'workspace-server/internal/handlers/registry.go'
+      - 'workspace-server/internal/handlers/workspace_restart.go'
+      - 'workspace-server/internal/registry/healthsweep.go'
+      - 'workspace-server/internal/registry/liveness.go'
+      - 'workspace-server/migrations/**'
+      - 'workspace-server/internal/db/workspace_status_enum_drift_test.go'
+      - 'tests/e2e/test_staging_external_runtime.sh'
+      - '.github/workflows/e2e-staging-external.yml'
+  workflow_dispatch:
+    inputs:
+      keep_org:
+        description: "Skip teardown for debugging (only via manual dispatch)"
+        required: false
+        type: boolean
+        default: false
+      stale_wait_secs:
+        description: "Seconds to wait for the heartbeat-staleness sweep (default 180 = 90s window + 90s buffer)"
+        required: false
+        default: "180"
+  schedule:
+    - cron: '30 7 * * *'
+
+concurrency:
+  group: e2e-staging-external
+  cancel-in-progress: false
+
+permissions:
+  contents: read
+
+jobs:
+  e2e-staging-external:
+    name: E2E Staging External Runtime
+    runs-on: ubuntu-latest
+    timeout-minutes: 25
+
+    env:
+      MOLECULE_CP_URL: https://staging-api.moleculesai.app
+      MOLECULE_ADMIN_TOKEN: ${{ secrets.MOLECULE_STAGING_ADMIN_TOKEN }}
+      E2E_RUN_ID: "${{ github.run_id }}-${{ github.run_attempt }}"
+      E2E_KEEP_ORG: ${{ github.event.inputs.keep_org && '1' || '0' }}
+      E2E_STALE_WAIT_SECS: ${{ github.event.inputs.stale_wait_secs || '180' }}
+
+    steps:
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+
+      - name: Verify admin token present
+        run: |
+          if [ -z "$MOLECULE_ADMIN_TOKEN" ]; then
+            # Schedule + push triggers must hard-fail when the token is
+            # missing — silent skip would mask infra rot. Manual dispatch
+            # gets the same hard-fail; an operator running this on a fork
+            # without secrets configured needs to know up-front.
+            echo "::error::MOLECULE_STAGING_ADMIN_TOKEN secret not set (Railway staging CP_ADMIN_API_TOKEN)"
+            exit 2
+          fi
+          echo "Admin token present ✓"
+
+      - name: CP staging health preflight
+        run: |
+          code=$(curl -sS -o /dev/null -w "%{http_code}" --max-time 10 "$MOLECULE_CP_URL/health")
+          if [ "$code" != "200" ]; then
+            echo "::error::Staging CP unhealthy (got HTTP $code). Skipping — not a workspace bug."
+            exit 1
+          fi
+          echo "Staging CP healthy ✓"
+
+      - name: Run external-runtime E2E
+        id: e2e
+        run: bash tests/e2e/test_staging_external_runtime.sh
+
+      # Mirror the e2e-staging-saas.yml safety net: if the runner is
+      # cancelled (e.g. concurrent staging push), the test script's
+      # EXIT trap may not fire, so we sweep e2e-ext-* slugs scoped to
+      # *this* run id.
+      - name: Teardown safety net (runs on cancel/failure)
+        if: always()
+        env:
+          ADMIN_TOKEN: ${{ secrets.MOLECULE_STAGING_ADMIN_TOKEN }}
+        run: |
+          set +e
+          orgs=$(curl -sS "$MOLECULE_CP_URL/cp/admin/orgs" \
+            -H "Authorization: Bearer $ADMIN_TOKEN" 2>/dev/null \
+            | python3 -c "
+          import json, sys, os, datetime
+          run_id = os.environ.get('GITHUB_RUN_ID', '')
+          d = json.load(sys.stdin)
+          # Scope STRICTLY to this run id (e2e-ext-YYYYMMDD-<runid>-...)
+          # so concurrent runs and unrelated dev probes are not touched.
+          # Sweep today AND yesterday so a midnight-crossing run still
+          # cleans up its own slug.
+          today = datetime.date.today()
+          yesterday = today - datetime.timedelta(days=1)
+          dates = (today.strftime('%Y%m%d'), yesterday.strftime('%Y%m%d'))
+          if not run_id:
+              # Without a run id we cannot scope safely; bail rather
+              # than risk deleting unrelated tenants.
+              sys.exit(0)
+          prefixes = tuple(f'e2e-ext-{d}-{run_id}-' for d in dates)
+          for o in d.get('orgs', []):
+              s = o.get('slug', '')
+              if s.startswith(prefixes) and o.get('status') != 'purged':
+                  print(s)
+          " 2>/dev/null)
+          if [ -n "$orgs" ]; then
+            echo "Safety-net sweep: deleting leftover orgs:"
+            echo "$orgs"
+            for slug in $orgs; do
+              curl -sS -X DELETE "$MOLECULE_CP_URL/cp/admin/tenants/$slug" \
+                -H "Authorization: Bearer $ADMIN_TOKEN" \
+                -H "Content-Type: application/json" \
+                -d "{\"confirm\":\"$slug\"}" >/dev/null 2>&1
+            done
+          else
+            echo "Safety-net sweep: no leftover orgs to clean."
+          fi
diff --git a/tests/e2e/test_staging_external_runtime.sh b/tests/e2e/test_staging_external_runtime.sh
new file mode 100755
index 00000000..68ca1b62
--- /dev/null
+++ b/tests/e2e/test_staging_external_runtime.sh
@@ -0,0 +1,348 @@
+#!/bin/bash
+# test_staging_external_runtime.sh — E2E regression for the
+# external-runtime workspace lifecycle on a real staging tenant.
+#
+# Why this test exists: the four/five sites that write 'awaiting_agent'
+# / 'hibernating' to workspaces.status had been silently failing in
+# production for five days (see migration 046) before a static drift
+# gate caught the enum gap. Unit tests passed because sqlmock matched
+# the SQL by regex but didn't enforce the live enum constraint, and
+# every existing E2E exercised hermes (not external) so the silent
+# failures never surfaced. This test pins the four awaiting_agent
+# transitions in real Postgres on a real staging tenant.
+#
+# Verification path:
+#   1. Provision a fresh tenant (test_staging_full_saas.sh harness shape).
+#   2. Create an external-runtime workspace with NO URL → assert
+#      response status == 'awaiting_agent' AND GET on the workspace
+#      returns the same. (Pre-fix the row stuck on 'provisioning'
+#      because the UPDATE in workspace.go:333 silently failed.)
+#   3. Register a fake URL via /registry/register → assert transition
+#      to 'online'. (Pre-fix this branch worked because it writes
+#      'online' which IS in the enum.)
+#   4. Stop heartbeating; wait past REMOTE_LIVENESS_STALE_AFTER (90s
+#      default) + a sweep interval → assert transition back to
+#      'awaiting_agent'. (Pre-fix the sweep UPDATE failed silently and
+#      the workspace stuck on 'online' indefinitely.)
+#
+# Hibernation is intentionally NOT covered here — it has its own timing
+# model (idle threshold) and warrants a separate harness.
+#
+# Required env (mirrors test_staging_full_saas.sh):
+#   MOLECULE_CP_URL          default: https://staging-api.moleculesai.app
+#   MOLECULE_ADMIN_TOKEN     CP admin bearer (Railway CP_ADMIN_API_TOKEN)
+#
+# Optional env:
+#   E2E_PROVISION_TIMEOUT_SECS  default 900 (15 min cold EC2 budget)
+#   E2E_KEEP_ORG                1 → skip teardown (debugging only)
+#   E2E_RUN_ID                  Slug suffix; CI: ${GITHUB_RUN_ID}
+#   E2E_STALE_WAIT_SECS         default 180 (90s window + 90s buffer)
+#   E2E_INTENTIONAL_FAILURE     1 → break a step on purpose to verify
+#                               the EXIT trap still tears down (mirrors
+#                               the full-saas harness's safety net).
+#
+# Exit codes: 0 happy, 1 generic, 2 missing env, 3 provision timeout,
+# 4 teardown leak.
+
+set -euo pipefail
+
+CP_URL="${MOLECULE_CP_URL:-https://staging-api.moleculesai.app}"
+ADMIN_TOKEN="${MOLECULE_ADMIN_TOKEN:?MOLECULE_ADMIN_TOKEN required — Railway staging CP_ADMIN_API_TOKEN}"
+PROVISION_TIMEOUT_SECS="${E2E_PROVISION_TIMEOUT_SECS:-900}"
+RUN_ID_SUFFIX="${E2E_RUN_ID:-$(date +%H%M%S)-$$}"
+STALE_WAIT_SECS="${E2E_STALE_WAIT_SECS:-180}"
+
+SLUG="e2e-ext-$(date +%Y%m%d)-${RUN_ID_SUFFIX}"
+SLUG=$(echo "$SLUG" | tr '[:upper:]' '[:lower:]' | tr -cd 'a-z0-9-' | head -c 32)
+
+log()  { echo "[$(date +%H:%M:%S)] $*"; }
+fail() { echo "[$(date +%H:%M:%S)] ❌ $*" >&2; exit 1; }
+ok()   { echo "[$(date +%H:%M:%S)] ✅ $*"; }
+
+CURL_COMMON=(-sS --fail-with-body --max-time 30)
+
+# ─── cleanup trap (mirrors full-saas) ────────────────────────────────────
+CLEANUP_DONE=0
+cleanup_org() {
+  local entry_rc=$?
+  if [ "$CLEANUP_DONE" = "1" ]; then return 0; fi
+  CLEANUP_DONE=1
+
+  if [ "${E2E_KEEP_ORG:-0}" = "1" ]; then
+    log "E2E_KEEP_ORG=1 → leaving $SLUG behind for inspection"
+    return 0
+  fi
+
+  log "Cleanup: deleting tenant $SLUG..."
+  curl "${CURL_COMMON[@]}" --max-time 120 -X DELETE "$CP_URL/cp/admin/tenants/$SLUG" \
+    -H "Authorization: Bearer $ADMIN_TOKEN" \
+    -H "Content-Type: application/json" \
+    -d "{\"confirm\":\"$SLUG\"}" >/dev/null 2>&1 \
+    && ok "Teardown request accepted" \
+    || log "Teardown returned non-2xx (may already be gone)"
+
+  local leak_count=1 elapsed=0
+  while [ "$elapsed" -lt 60 ]; do
+    leak_count=$(curl "${CURL_COMMON[@]}" "$CP_URL/cp/admin/orgs" \
+      -H "Authorization: Bearer $ADMIN_TOKEN" 2>/dev/null \
+      | python3 -c "import json,sys; d=json.load(sys.stdin); print(sum(1 for o in d.get('orgs', []) if o.get('slug')=='$SLUG' and o.get('status') != 'purged'))" \
+      2>/dev/null || echo 1)
+    [ "$leak_count" = "0" ] && break
+    sleep 5
+    elapsed=$((elapsed + 5))
+  done
+
+  if [ "$leak_count" != "0" ]; then
+    echo "⚠️  LEAK: org $SLUG still present post-teardown (count=$leak_count)" >&2
+    exit 4
+  fi
+  ok "Teardown clean — no orphan resources for $SLUG (${elapsed}s)"
+
+  case "$entry_rc" in
+    0|1|2|3|4) ;;
+    *) exit 1 ;;
+  esac
+}
+trap cleanup_org EXIT INT TERM
+
+# ─── 0. Preflight ───────────────────────────────────────────────────────
+log "═══════════════════════════════════════════════════════════════════"
+log " Staging external-runtime E2E (regression for migration 046)"
+log "   CP:    $CP_URL"
+log "   Slug:  $SLUG"
+log "   Stale: ${STALE_WAIT_SECS}s wait window"
+log "═══════════════════════════════════════════════════════════════════"
+
+curl "${CURL_COMMON[@]}" "$CP_URL/health" >/dev/null || fail "CP health check failed"
+ok "CP reachable"
+
+admin_call() {
+  local method="$1"; shift; local path="$1"; shift
+  curl "${CURL_COMMON[@]}" -X "$method" "$CP_URL$path" \
+    -H "Authorization: Bearer $ADMIN_TOKEN" \
+    -H "Content-Type: application/json" "$@"
+}
+
+# ─── 1. Create org ──────────────────────────────────────────────────────
+log "1/8 Creating org $SLUG..."
+CREATE_RESP=$(admin_call POST /cp/admin/orgs \
+  -d "{\"slug\":\"$SLUG\",\"name\":\"E2E ext $SLUG\",\"owner_user_id\":\"e2e-runner:$SLUG\"}")
+ORG_ID=$(echo "$CREATE_RESP" | python3 -c "import json,sys; print(json.load(sys.stdin).get('id',''))")
+[ -z "$ORG_ID" ] && fail "Org create response missing 'id'"
+ok "Org created (id=$ORG_ID)"
+
+# ─── 2. Wait for tenant provisioning ────────────────────────────────────
+# Terminal status from /cp/admin/orgs is 'running' (org_instances.status),
+# NOT 'ready' — same field the full-saas harness polls. 'failed' surfaces
+# diagnostic dump and aborts. See test_staging_full_saas.sh step 2 for
+# the field-bugfix history (2026-04-21, last_error path).
+log "2/8 Waiting for tenant (up to ${PROVISION_TIMEOUT_SECS}s)..."
+DEADLINE=$(( $(date +%s) + PROVISION_TIMEOUT_SECS ))
+LAST_STATUS=""
+while true; do
+  if [ "$(date +%s)" -gt "$DEADLINE" ]; then
+    fail "Tenant provisioning timed out (last: $LAST_STATUS)"
+  fi
+  LIST_JSON=$(admin_call GET /cp/admin/orgs 2>/dev/null || echo '{"orgs":[]}')
+  STATUS=$(echo "$LIST_JSON" | python3 -c "
+import json, sys
+d = json.load(sys.stdin)
+for o in d.get('orgs', []):
+    if o.get('slug') == '$SLUG':
+        print(o.get('instance_status', ''))
+        sys.exit(0)
+print('')
+" 2>/dev/null || echo "")
+  if [ "$STATUS" != "$LAST_STATUS" ]; then
+    log "   instance_status: $STATUS"
+    LAST_STATUS="$STATUS"
+  fi
+  case "$STATUS" in
+    running) break ;;
+    failed)
+      log "── DIAGNOSTIC BURST (step 2 — tenant provisioning failed) ──"
+      echo "$LIST_JSON" | python3 -c "
+import json, sys
+d = json.load(sys.stdin)
+for o in d.get('orgs', []):
+    if o.get('slug') == '$SLUG':
+        print(json.dumps(o, indent=2))
+        sys.exit(0)
+print('(no org row found for slug=$SLUG — DB drift?)')
+" 2>&1 | sed 's/^/  /'
+      log "── END DIAGNOSTIC ──"
+      fail "Tenant provisioning failed for $SLUG (see diagnostic above)"
+      ;;
+    *) sleep 15 ;;
+  esac
+done
+ok "Tenant provisioning complete"
+
+# Derive tenant URL the same way the full-saas harness does.
+CP_HOST=$(echo "$CP_URL" | sed -E 's#^https?://##; s#/.*$##')
+case "$CP_HOST" in
+  api.*)         DERIVED_DOMAIN="${CP_HOST#api.}" ;;
+  staging-api.*) DERIVED_DOMAIN="staging.${CP_HOST#staging-api.}" ;;
+  *)             DERIVED_DOMAIN="$CP_HOST" ;;
+esac
+TENANT_DOMAIN="${MOLECULE_TENANT_DOMAIN:-$DERIVED_DOMAIN}"
+TENANT_URL="https://$SLUG.$TENANT_DOMAIN"
+log "    TENANT_URL=$TENANT_URL"
+
+# ─── 3. Per-tenant admin token + TLS readiness ──────────────────────────
+log "3/8 Fetching per-tenant admin token..."
+TENANT_TOKEN_RESP=$(admin_call GET "/cp/admin/orgs/$SLUG/admin-token")
+TENANT_TOKEN=$(echo "$TENANT_TOKEN_RESP" | python3 -c "import json,sys; print(json.load(sys.stdin).get('admin_token',''))")
+[ -z "$TENANT_TOKEN" ] && fail "Could not retrieve per-tenant admin token"
+ok "Token retrieved (len=${#TENANT_TOKEN})"
+
+log "Waiting for tenant TLS / DNS..."
+TLS_DEADLINE=$(( $(date +%s) + 15 * 60 ))
+while true; do
+  if curl -sSfk --max-time 5 "$TENANT_URL/health" >/dev/null 2>&1; then break; fi
+  if [ "$(date +%s)" -gt "$TLS_DEADLINE" ]; then
+    fail "Tenant URL never responded 2xx on /health within 15min"
+  fi
+  sleep 5
+done
+ok "Tenant reachable"
+
+tenant_call() {
+  local method="$1"; shift; local path="$1"; shift
+  curl "${CURL_COMMON[@]}" -X "$method" "$TENANT_URL$path" \
+    -H "Authorization: Bearer $TENANT_TOKEN" \
+    -H "X-Molecule-Org-Id: $ORG_ID" \
+    "$@"
+}
+
+# ─── 4. Create external workspace (no URL) ──────────────────────────────
+# This is the FIRST silent-failure path (workspace.go:333). Pre-migration
+# 046, the response would say status=awaiting_agent but the row stuck
+# on whatever the create handler set first (typically 'provisioning')
+# because the follow-up UPDATE failed the enum cast.
+log "4/8 Creating external workspace (no URL — exercises workspace.go:333)..."
+WS_CREATE_RESP=$(tenant_call POST /workspaces \
+  -d '{"name":"ext-e2e","runtime":"external","external":true}')
+
+WS_ID=$(echo "$WS_CREATE_RESP" | python3 -c "import json,sys; print(json.load(sys.stdin).get('id',''))")
+WS_RESP_STATUS=$(echo "$WS_CREATE_RESP" | python3 -c "import json,sys; print(json.load(sys.stdin).get('status',''))")
+WS_AUTH_TOKEN=$(echo "$WS_CREATE_RESP" | python3 -c "
+import json,sys
+try:
+    d = json.load(sys.stdin)
+    conn = d.get('connection') or {}
+    print(conn.get('auth_token','') or d.get('auth_token',''))
+except Exception:
+    print('')
+")
+[ -z "$WS_ID" ] && fail "Workspace create missing id: $WS_CREATE_RESP"
+[ "$WS_RESP_STATUS" != "awaiting_agent" ] && fail "Expected response status=awaiting_agent, got $WS_RESP_STATUS"
+ok "Workspace created (id=$WS_ID, response status=awaiting_agent)"
+
+# This GET is the proof that the row actually has the value (not just
+# the response body lying). Pre-migration-046 the UPDATE would have
+# silently failed and this would return whatever 'provisioning' the
+# initial INSERT left. Post-fix it must be 'awaiting_agent'.
+log "    Verifying DB row..."
+GET_RESP=$(tenant_call GET "/workspaces/$WS_ID")
+DB_STATUS=$(echo "$GET_RESP" | python3 -c "import json,sys; print(json.load(sys.stdin).get('status',''))")
+[ "$DB_STATUS" != "awaiting_agent" ] && fail "DB row status=$DB_STATUS (expected awaiting_agent — migration 046 likely not applied)"
+ok "DB row stored as awaiting_agent (proof migration 046 applied)"
+
+# ─── 5. Register the workspace (transitions to online) ──────────────────
+# Pre-fix this path was actually fine because it writes 'online', a value
+# already in the enum. We exercise it anyway because the registration
+# implicitly walks resolveDeliveryMode (registry.go:resolveDeliveryMode),
+# which DOES read runtime + apply the new poll-default introduced by
+# PR #2382.
+log "5/8 Registering workspace via /registry/register..."
+[ -z "$WS_AUTH_TOKEN" ] && fail "No workspace auth token returned — register impossible"
+# Payload contract (workspace-server/internal/models/workspace.go RegisterPayload):
+#   id            — required, the workspace UUID (NOT "workspace_id" — that's the
+#                   heartbeat payload field; mixing them yields a 400 from
+#                   ShouldBindJSON because `id` has binding:"required").
+#   agent_card    — required (binding:"required"); minimal valid card is name+skills.
+#   delivery_mode — set explicitly to "poll" so url validation is skipped
+#                   regardless of whether the deployed image has the
+#                   runtime=external→poll default from PR #2382. Observed
+#                   2026-04-30 17:18Z: a freshly-provisioned staging tenant
+#                   was running an older workspace-server :latest image
+#                   that lacked resolveDeliveryMode's external→poll branch,
+#                   so the implicit default was push and validateAgentURL
+#                   400'd on example.invalid. Asserting on the implicit
+#                   default makes the *register call* itself fragile to
+#                   image-tag drift on the fleet — verify the default
+#                   separately (step 5b assertion) without depending on it
+#                   here.
+#   url           — accepted but not dispatched-to in poll mode, so
+#                   example.invalid is a valid sentinel.
+REGISTER_BODY=$(printf '{"id":"%s","url":"https://example.invalid:443","delivery_mode":"poll","agent_card":{"name":"e2e-ext","skills":[{"id":"echo","name":"Echo"}]}}' "$WS_ID")
+# Disable --fail-with-body for this one call so a 4xx surfaces the response
+# body (the bare CURL_COMMON would `set -e`-kill before we could log it).
+REGISTER_RESP=$(curl -sS --max-time 30 -w "\nHTTP_CODE=%{http_code}" -X POST "$TENANT_URL/registry/register" \
+  -H "Authorization: Bearer $WS_AUTH_TOKEN" \
+  -H "X-Molecule-Org-Id: $ORG_ID" \
+  -H "Content-Type: application/json" \
+  -d "$REGISTER_BODY") || true
+log "    register response: $(echo "$REGISTER_RESP" | head -c 300)"
+echo "$REGISTER_RESP" | grep -q "HTTP_CODE=200" || fail "register returned non-200 — see body above"
+
+GET_RESP=$(tenant_call GET "/workspaces/$WS_ID")
+ONLINE_STATUS=$(echo "$GET_RESP" | python3 -c "import json,sys; print(json.load(sys.stdin).get('status',''))")
+[ "$ONLINE_STATUS" != "online" ] && fail "Expected online after register, got $ONLINE_STATUS"
+ok "Workspace transitioned to online"
+
+# Confirm the register handler echoed back delivery_mode=poll. We read
+# this from the register RESPONSE, not the workspace GET response, because
+# the GET handler's SELECT (workspace.go:597) doesn't fetch delivery_mode
+# — its column list pre-dates the delivery_mode column from #2339 PR 1.
+# Surfacing delivery_mode in GET is tracked separately; not gating on it
+# here keeps this test focused on the awaiting_agent transitions.
+REGISTER_BODY_JSON=$(echo "$REGISTER_RESP" | head -n 1)
+REGISTER_DELIVERY_MODE=$(echo "$REGISTER_BODY_JSON" | python3 -c "import json,sys; print(json.load(sys.stdin).get('delivery_mode',''))")
+if [ "$REGISTER_DELIVERY_MODE" = "poll" ]; then
+  ok "delivery_mode=poll (register response echoed explicit value)"
+else
+  fail "Register response delivery_mode=$REGISTER_DELIVERY_MODE (expected poll). Body: $REGISTER_BODY_JSON"
+fi
+
+# ─── 6. Stop heartbeating; wait past REMOTE_LIVENESS_STALE_AFTER ────────
+# This is the SECOND silent-failure path (registry/healthsweep.go's
+# sweepStaleRemoteWorkspaces). Pre-migration-046 the heartbeat-staleness
+# UPDATE silently failed and the workspace stuck on 'online' forever
+# even though no agent was alive. We wait the full window + a sweep
+# interval and assert the row transitions back to 'awaiting_agent'.
+log "6/8 Waiting ${STALE_WAIT_SECS}s for heartbeat-staleness sweep (no heartbeat sent)..."
+sleep "$STALE_WAIT_SECS"
+
+GET_RESP=$(tenant_call GET "/workspaces/$WS_ID")
+STALE_STATUS=$(echo "$GET_RESP" | python3 -c "import json,sys; print(json.load(sys.stdin).get('status',''))")
+[ "$STALE_STATUS" != "awaiting_agent" ] && \
+  fail "After ${STALE_WAIT_SECS}s with no heartbeat, expected status=awaiting_agent (sweep transition), got $STALE_STATUS — migration 046 likely not applied OR sweep not running"
+ok "Heartbeat-staleness sweep transitioned online → awaiting_agent (proof healthsweep.go fix working)"
+
+# ─── 7. Re-register and confirm we can come back online ─────────────────
+# This proves the awaiting_agent state is recoverable (re-registrable),
+# which is the whole point of using it instead of 'offline'.
+log "7/8 Re-registering after stale → confirming recovery to online..."
+# Same payload contract as step 5 (id + agent_card both required). See note
+# there for why workspace_id would 400.
+REREG_RESP=$(curl -sS --max-time 30 -w "\nHTTP_CODE=%{http_code}" -X POST "$TENANT_URL/registry/register" \
+  -H "Authorization: Bearer $WS_AUTH_TOKEN" \
+  -H "X-Molecule-Org-Id: $ORG_ID" \
+  -H "Content-Type: application/json" \
+  -d "$REGISTER_BODY") || true
+log "    re-register response: $(echo "$REREG_RESP" | head -c 300)"
+echo "$REREG_RESP" | grep -q "HTTP_CODE=200" || fail "re-register returned non-200 — see body above"
+
+GET_RESP=$(tenant_call GET "/workspaces/$WS_ID")
+RECOVERED_STATUS=$(echo "$GET_RESP" | python3 -c "import json,sys; print(json.load(sys.stdin).get('status',''))")
+[ "$RECOVERED_STATUS" != "online" ] && \
+  fail "Expected re-register to return workspace to online, got $RECOVERED_STATUS"
+ok "Re-register succeeded — awaiting_agent → online (operator-recoverable)"
+
+# ─── 8. Done — cleanup runs in the EXIT trap ───────────────────────────
+log "8/8 All four awaiting_agent transitions verified."
+log "═══════════════════════════════════════════════════════════════════"
+ok "External-runtime E2E PASSED on $SLUG"
+log "═══════════════════════════════════════════════════════════════════"