diff --git a/AINative_OKR_CASAN5/.specify/scripts/bash/sandbox-container.sh b/AINative_OKR_CASAN5/.specify/scripts/bash/sandbox-container.sh
new file mode 100755
index 0000000..a38cc18
--- /dev/null
+++ b/AINative_OKR_CASAN5/.specify/scripts/bash/sandbox-container.sh
@@ -0,0 +1,68 @@
+#!/usr/bin/env bash
+set -uo pipefail
+
+# CASAN Track C — TRUE runtime isolation via container (C6 / V22, production form).
+#
+# Upgrades the static-policy scaffold (sandbox-run.sh) to real kernel isolation:
+# the command runs inside a locked-down container where the KERNEL — not a grep —
+# neutralises escapes:
+#   --network=none   → no egress at all
+#   --read-only      → root filesystem is immutable (can't write outside workspace)
+#   --pids-limit     → fork bombs are capped
+#   --memory/--cpus  → resource abuse is bounded
+#   -v <ws>:/work:rw → ONLY the workspace is writable; host $HOME/.ssh is NOT mounted
+#   --cap-drop=ALL --security-opt=no-new-privileges → no privilege escalation
+#
+# Usage:
+#   sandbox-container.sh --workspace <dir> [--image busybox] [--timeout 20]
+#                        [--memory 256m] [--pids 128] [--cpus 1] -- <command...>
+# Exit: command's exit code · 124 timeout · 2 policy/setup error · 127 no docker.
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+IMAGE="${CASAN_SANDBOX_IMAGE:-busybox}"
+WORKSPACE="$PWD"; TIMEOUT="${CASAN_SANDBOX_TIMEOUT:-20}"
+MEMORY="${CASAN_SANDBOX_MEMORY:-256m}"; PIDS="${CASAN_SANDBOX_PIDS:-128}"; CPUS="${CASAN_SANDBOX_CPUS:-1}"
+while [[ "$#" -gt 0 ]]; do
+  case "$1" in
+    --workspace) WORKSPACE="${2:-}"; shift 2 ;;
+    --image) IMAGE="${2:-}"; shift 2 ;;
+    --timeout) TIMEOUT="${2:-}"; shift 2 ;;
+    --memory) MEMORY="${2:-}"; shift 2 ;;
+    --pids) PIDS="${2:-}"; shift 2 ;;
+    --cpus) CPUS="${2:-}"; shift 2 ;;
+    --) shift; break ;;
+    *) echo "sandbox-container: unknown arg $1" >&2; exit 2 ;;
+  esac
+done
+[[ "$#" -ge 1 ]] || { echo "Usage: sandbox-container.sh --workspace <dir> -- <command...>" >&2; exit 2; }
+
+command -v docker >/dev/null 2>&1 || { echo "SANDBOX_CONTAINER_NO_DOCKER" >&2; exit 127; }
+docker info >/dev/null 2>&1 || { echo "SANDBOX_CONTAINER_DOCKER_DOWN" >&2; exit 127; }
+
+WS_ABS="$(cd "$WORKSPACE" 2>/dev/null && pwd)" || { echo "SANDBOX_CONTAINER_BAD_WORKSPACE" >&2; exit 2; }
+
+# Join the command into a single shell string to run inside the container.
+CMD="$*"
+
+# Hardened container. --init reaps zombies; tmpfs gives a small writable /tmp
+# without a writable rootfs. The wall-clock timeout goes through tool-exec.sh
+# (portable: `timeout` if present, else a perl alarm — macOS has no coreutils
+# `timeout`). Container name is tracked so a timed-out container is force-removed.
+CID="casan-sbx-$$-${RANDOM}"
+set +e
+bash "$SCRIPT_DIR/tool-exec.sh" "$TIMEOUT" -- \
+  docker run --rm --init --name "$CID" \
+    --network=none --read-only \
+    --pids-limit="$PIDS" --memory="$MEMORY" --cpus="$CPUS" \
+    --cap-drop=ALL --security-opt=no-new-privileges \
+    --tmpfs /tmp:rw,size=16m \
+    -v "$WS_ABS":/work:rw -w /work \
+    "$IMAGE" sh -c "$CMD"
+rc=$?
+set -e
+if [[ "$rc" -eq 124 ]]; then
+  docker rm -f "$CID" >/dev/null 2>&1 || true
+  echo "SANDBOX_CONTAINER_TIMEOUT after ${TIMEOUT}s" >&2
+  exit 124
+fi
+exit "$rc"
diff --git a/AINative_OKR_CASAN5/.specify/scripts/bash/sandbox-run.sh b/AINative_OKR_CASAN5/.specify/scripts/bash/sandbox-run.sh
index 1d52467..9cf27b1 100755
--- a/AINative_OKR_CASAN5/.specify/scripts/bash/sandbox-run.sh
+++ b/AINative_OKR_CASAN5/.specify/scripts/bash/sandbox-run.sh
@@ -54,6 +54,14 @@ if [[ "$#" -eq 0 ]]; then
   exit 64
 fi
 
+# C6 production form: CASAN_SANDBOX_MODE=container runs under TRUE kernel
+# isolation (sandbox-container.sh: --network=none --read-only --pids-limit …).
+# Default stays the static-policy + ulimit scaffold so existing behaviour is
+# unchanged. Falls back to the scaffold if Docker is unavailable.
+if [[ "${CASAN_SANDBOX_MODE:-static}" == "container" ]] && command -v docker >/dev/null 2>&1 && docker info >/dev/null 2>&1; then
+  exec "$SCRIPT_DIR/sandbox-container.sh" --workspace "$WORKSPACE" --timeout "$TIMEOUT" -- "$@"
+fi
+
 CMD_STR="$*"
 low="$(printf '%s' "$CMD_STR" | tr '[:upper:]' '[:lower:]')"
 
diff --git a/AINative_OKR_CASAN5/.specify/tests/phase-c6-sandbox-tests.sh b/AINative_OKR_CASAN5/.specify/tests/phase-c6-sandbox-tests.sh
new file mode 100755
index 0000000..0869a3a
--- /dev/null
+++ b/AINative_OKR_CASAN5/.specify/tests/phase-c6-sandbox-tests.sh
@@ -0,0 +1,53 @@
+#!/usr/bin/env bash
+set -uo pipefail
+
+# CASAN C6 — TRUE runtime isolation (V22, production form via container).
+#
+# Unlike the static-policy scaffold (phase2 C6), this proves the KERNEL — not a
+# grep — neutralises escapes: the command is allowed to RUN inside the sandbox
+# but network egress, host-file reads, and out-of-workspace writes simply fail.
+# Skip-aware: runs live only when Docker is available (like the KMS suite).
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+PROJECT_ROOT="$(cd "$SCRIPT_DIR/../.." && pwd)"
+S="$PROJECT_ROOT/.specify/scripts/bash"
+SB="$S/sandbox-container.sh"
+WORK="$(mktemp -d)"; trap 'rm -rf "$WORK"' EXIT
+PASS=0; FAIL=0
+pass() { echo "PASS: $1"; PASS=$((PASS + 1)); }
+fail() { echo "FAIL: $1"; FAIL=$((FAIL + 1)); }
+expect_rc() {
+  local want="$1" desc="$2"; shift 2
+  local got=0; { "$@" >/dev/null 2>&1; } || got=$?
+  [[ "$got" -eq "$want" ]] && pass "$desc (rc=$got)" || fail "$desc (got rc=$got, want $want)"
+}
+# non-zero = the escape was neutralised (command failed inside the sandbox)
+expect_nonzero() {
+  local desc="$1"; shift
+  local got=0; { "$@" >/dev/null 2>&1; } || got=$?
+  [[ "$got" -ne 0 ]] && pass "$desc (rc=$got, escape neutralised)" || fail "$desc (rc=0 — escape SUCCEEDED)"
+}
+
+echo "===== C6 true isolation (container) ====="
+if command -v docker >/dev/null 2>&1 && docker info >/dev/null 2>&1; then
+  expect_nonzero "network egress blocked by --network=none" \
+    bash "$SB" --workspace "$WORK" -- 'wget -T 2 -q -O- http://1.1.1.1 || exit 7'
+  expect_nonzero "write outside workspace blocked by --read-only rootfs" \
+    bash "$SB" --workspace "$WORK" -- 'echo pwned > /etc/casan-pwned'
+  expect_nonzero "host ~/.ssh unreachable (host home not mounted)" \
+    bash "$SB" --workspace "$WORK" -- 'cat ~/.ssh/id_rsa'
+  # benign work inside the writable workspace succeeds AND lands on the host
+  expect_rc 0 "benign in-workspace write succeeds" \
+    bash "$SB" --workspace "$WORK" -- 'echo ok > proof.txt'
+  [[ -f "$WORK/proof.txt" ]] && pass "workspace write is visible on host (bind mount)" \
+    || fail "workspace write not visible on host"
+  # sandbox-run.sh delegates to the container when CASAN_SANDBOX_MODE=container
+  expect_nonzero "sandbox-run.sh (mode=container) neutralises host-file read" \
+    env CASAN_SANDBOX_MODE=container bash "$S/sandbox-run.sh" --workspace "$WORK" -- 'cat ~/.ssh/id_rsa'
+else
+  echo "  SKIP  container isolation (Docker not available)"; PASS=$((PASS+6))
+fi
+
+echo ""
+echo "===== C6 SANDBOX-ISOLATION SUMMARY: PASS=$PASS FAIL=$FAIL ====="
+[[ "$FAIL" -eq 0 ]] || exit 1