diff --git a/.dockerignore b/.dockerignore
index ab6a1f8..05ec59a 100644
--- a/.dockerignore
+++ b/.dockerignore
@@ -2,3 +2,4 @@
 !Dockerfile
 !docker/entrypoint.sh
 !target/release/omnigraph-server
+!target/release/omnigraph
diff --git a/Dockerfile b/Dockerfile
index e49a6c7..ca22a93 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -11,9 +11,13 @@ RUN groupadd --system omnigraph \
     && useradd --system --gid omnigraph --create-home --home-dir /var/lib/omnigraph omnigraph
 
 COPY target/release/omnigraph-server /usr/local/bin/omnigraph-server
+# The CLI ships in the image so the cluster day-2 loop (cluster
+# apply/approve/status, data loads by explicit URI) runs in-container via
+# `docker exec` / ECS exec / `railway shell` — no omnigraph.yaml required.
+COPY target/release/omnigraph /usr/local/bin/omnigraph
 COPY docker/entrypoint.sh /usr/local/bin/omnigraph-entrypoint
 
-RUN chmod 0755 /usr/local/bin/omnigraph-server /usr/local/bin/omnigraph-entrypoint
+RUN chmod 0755 /usr/local/bin/omnigraph-server /usr/local/bin/omnigraph /usr/local/bin/omnigraph-entrypoint
 
 ENV OMNIGRAPH_BIND=0.0.0.0:8080
 
diff --git a/docker/entrypoint.sh b/docker/entrypoint.sh
index a5fb275..98587aa 100644
--- a/docker/entrypoint.sh
+++ b/docker/entrypoint.sh
@@ -9,6 +9,17 @@ fi
 
 bind="${OMNIGRAPH_BIND:-0.0.0.0:8080}"
 
+# Cluster mode first, and exclusive (the server's mode-inference rule 0):
+# a deployment serves from cluster state XOR omnigraph.yaml, never a merge.
+# Fail fast here with the same contract the server enforces.
+if [ -n "${OMNIGRAPH_CLUSTER:-}" ]; then
+  if [ -n "${OMNIGRAPH_TARGET_URI:-}" ] || [ -n "${OMNIGRAPH_CONFIG:-}" ] || [ -n "${OMNIGRAPH_TARGET:-}" ]; then
+    echo "OMNIGRAPH_CLUSTER is an exclusive boot source; unset OMNIGRAPH_TARGET_URI/OMNIGRAPH_CONFIG/OMNIGRAPH_TARGET" >&2
+    exit 64
+  fi
+  exec "$SERVER_BIN" --cluster "${OMNIGRAPH_CLUSTER}" --bind "${bind}"
+fi
+
 # URI comes from the env var (the positional arg wins over any config
 # `graphs` block in resolve_target_uri). OMNIGRAPH_CONFIG, when also set,
 # is forwarded as --config purely to supply a policy file — the two
@@ -28,6 +39,8 @@ fi
 
 cat >&2 <<'EOF'
 omnigraph-server container startup requires one of:
+  - OMNIGRAPH_CLUSTER     (serve a cluster directory's applied revision;
+                           exclusive — cannot combine with the others)
   - OMNIGRAPH_TARGET_URI
   - OMNIGRAPH_CONFIG
 
diff --git a/docker/entrypoint_test.sh b/docker/entrypoint_test.sh
index 01fbee2..3ee668f 100755
--- a/docker/entrypoint_test.sh
+++ b/docker/entrypoint_test.sh
@@ -58,6 +58,26 @@ got=$(sh "$ep" some-uri --bind 1.2.3.4:9 --extra)
 check "explicit args passthrough" \
   "ARGS: some-uri --bind 1.2.3.4:9 --extra" "$got"
 
+got=$(OMNIGRAPH_CLUSTER="/var/lib/omnigraph/company-brain" OMNIGRAPH_BIND="0.0.0.0:8080" sh "$ep")
+check "CLUSTER only (Phase 5 mode switch)" \
+  "ARGS: --cluster /var/lib/omnigraph/company-brain --bind 0.0.0.0:8080" "$got"
+
+# Exclusivity: OMNIGRAPH_CLUSTER refuses every combination, exit 64.
+for combo in "OMNIGRAPH_TARGET_URI=s3://b/g" "OMNIGRAPH_CONFIG=/etc/o.yaml" "OMNIGRAPH_TARGET=active"; do
+  if out=$(env "$combo" OMNIGRAPH_CLUSTER="/data/cluster" sh "$ep" 2>&1); then
+    echo "FAIL: CLUSTER + ${combo%%=*} unexpectedly succeeded: $out"
+    fail=1
+  else
+    status=$?
+    if [ "$status" -ne 64 ]; then
+      echo "FAIL: CLUSTER + ${combo%%=*} exited $status, want 64"
+      fail=1
+    else
+      echo "ok: CLUSTER + ${combo%%=*} refused (64)"
+    fi
+  fi
+done
+
 if [ "$fail" -ne 0 ]; then
   echo "entrypoint_test: FAILED"
   exit 1