fix(runtime): enforce functional containment after closing execution bypasses (ODY-141)

src/agent_tools/subprocess_tools.py

@@ -388,7 +388,7 @@ def _contained_command(
     comparable — one is a mount namespace, the other is a regex — and choosing
     the second silently means an uncontained host execution reads in the
     transcript exactly like a contained one. The fallback still happens under
-    report-only mode, which is what ships; the difference is that it is now
+    an explicit report-only diagnostic mode; the difference is that it is now
     recorded in the result.
 
     :raises containment.ContainmentUnavailable: filesystem containment could
@@ -399,7 +399,7 @@ def _contained_command(
         content, cwd, chdir=chdir, interpreter_prefix=interpreter_prefix,
     )
     # The probe's filesystem answer and the wrapper's None/not-None answer rest
-    # on the same condition (`not IS_WINDOWS and which("bwrap")`), so they agree
+    # on the same functional namespace probe, so they agree
     # by construction. `wrapped` is still what decides, because it is what
     # actually runs: a probe that said yes to a wrapper that declined would be
     # the same false claim in the other direction.
@@ -449,41 +449,9 @@ def _wrap_workspace_namespace(
     bubblewrap namespace preserves that public contract for each concurrent
     agent without creating a process-global /workspace symlink.
     """
-    if IS_WINDOWS or not shutil.which("bwrap"):
+    if IS_WINDOWS or not containment._bwrap_available():
         return None
-    args = [
-        "bwrap", "--die-with-parent", "--new-session", "--tmpfs", "/",
-        "--dir", "/usr", "--ro-bind", "/usr", "/usr",
-        "--symlink", "usr/bin", "/bin",
-        "--symlink", "usr/lib", "/lib",
-        "--symlink", "usr/lib64", "/lib64",
-        "--symlink", "usr/bin", "/sbin",
-        "--dir", "/etc", "--ro-bind", "/etc", "/etc",
-        # Read-only, not read-write. These two binds exist so a command can
-        # *read* host material it legitimately needs — a dataset under /mnt, a
-        # dotfile under /home. Binding them writable gave back most of what
-        # the namespace was for: a Linux host with working bubblewrap running
-        # this argv reaches outside the workspace and writes to the user's home
-        # directory, measured rather than inferred. The workspace bind below is
-        # the one writable path, which is what "workspace confinement" means.
-        "--dir", "/home", "--ro-bind", "/home", "/home",
-        "--dir", "/mnt", "--ro-bind", "/mnt", "/mnt",
-        "--dir", "/tmp", "--tmpfs", "/tmp",
-        "--dev-bind", "/dev", "/dev", "--proc", "/proc",
-        "--dir", WORKSPACE_MOUNT, "--bind", cwd, WORKSPACE_MOUNT,
-    ]
-    # The workspace stays writable at its real host path as well as at
-    # /workspace. A command can carry the absolute host path: BashTool's own
-    # /tmp redirect rewrites `/tmp/` to `<agent_cwd()>/.tmp/` before the
-    # namespace is built, so the command reaching bwrap already names the real
-    # path. Before /home and /mnt became read-only those writes landed only
-    # because the workspace happened to sit under one of them. Binding the
-    # workspace itself is the narrow version of what that accident provided:
-    # the same directory by either name, and nothing else writable.
-    real_cwd = os.path.realpath(cwd)
-    if real_cwd not in _NAMESPACE_RESERVED_DESTS and len(real_cwd.split(os.sep)) >= 3:
-        args.extend(_namespace_dir_chain(real_cwd))
-        args.extend(("--bind", real_cwd, real_cwd))
+    readonly = [path for path in ("/home", "/mnt") if os.path.isdir(path)]
     # setup-python installs interpreters under /opt, and local CI virtualenvs
     # can live under /tmp. Those paths are hidden by the private root/tmpfs.
     # Expose only the active interpreter environment, read-only, so Python
@@ -513,9 +481,14 @@ def _wrap_workspace_namespace(
             and os.path.isdir(prefix)
             and has_environment_layout
         ):
-            args.extend(_namespace_dir_chain(prefix))
-            args.extend(("--ro-bind", prefix, prefix))
-    args.extend(("--chdir", chdir, "/bin/bash", "-lc", content))
+            readonly.append(prefix)
+    spec = containment.ContainmentSpec(
+        workspace=cwd, env={}, wall_clock_s=DEFAULT_BASH_TIMEOUT,
+        readonly_extra=tuple(readonly),
+    )
+    args = containment._bwrap_prefix(spec)
+    args[-1] = chdir
+    args.extend(("/bin/bash", "-lc", content))
     return shlex.join(args)
 
 
@@ -524,7 +497,8 @@ def _owned_spec(cwd: str, env: Optional[dict], timeout: int, readonly_extra: tup
     readonly = []
     for prefix in (sys.prefix, sys.base_prefix):
         prefix = os.path.realpath(prefix)
-        if not _namespace_visible_without_bind(prefix) and prefix not in _NAMESPACE_RESERVED_DESTS:
+        visible = any(prefix == root or prefix.startswith(root + os.sep) for root in ("/usr", "/etc"))
+        if not visible and prefix not in _NAMESPACE_RESERVED_DESTS:
             readonly.append(prefix)
     return containment.agent_spec(
         cwd, dict(os.environ if env is None else env), timeout,
@@ -551,8 +525,12 @@ async def _run_owned_command(command, ctx: dict, *, tool: str, timeout: int, arg
     except containment.ContainmentUnavailable as exc:
         return containment.unavailable_tool_result(exc, tool=tool)
     except (OSError, RuntimeError, ValueError) as exc:
+        boundary = grant.to_dict() if grant else {}
+        boundary["executed"] = bool(getattr(exc, "containment_executed", False))
+        if not getattr(exc, "containment_established", False):
+            boundary.update(contained=False, enforced=[])
         return {"error": f"{tool}: execution failed: {exc}", "exit_code": 1,
-                "containment": grant.to_dict() if grant else {"contained": False, "executed": False}}
+                "containment": boundary}
 
     boundary = result.grant.to_dict()
     boundary["executed"] = True

src/containment.py

@@ -39,11 +39,10 @@ deployment detail.
 * :data:`MODE_REPORT_ONLY` — the same shortfall is recorded on the grant as
   ``unenforced_required``, logged once, and the command runs.
 
-The shipped default is report-only. On macOS and in the shipped Docker image
-there is no ``bwrap``, so enforcing filesystem containment by default would turn
-every ``bash`` call into a refusal the moment this module is wired up. Starting
-report-only makes that landing observable instead of breaking, and flipping the
-constant is reversible in a way that breaking every host is not.
+The shipped default is enforcing. Hosts without functional namespaces refuse
+native agent execution requiring filesystem and process-tree containment.
+Report-only remains an explicit internal diagnostic posture, never a tool or
+deployment setting. Networking is inherited unless the spec requests isolation.
 """
 
 from __future__ import annotations
@@ -54,6 +53,7 @@ import json
 import logging
 import os
 import shutil
+import select
 import signal
 import subprocess
 import sys
@@ -81,10 +81,8 @@ logger = logging.getLogger(__name__)
 MODE_ENFORCING = "enforcing"
 MODE_REPORT_ONLY = "report_only"
 
-#: Ship report-only; see the module docstring for why this is the reversible
-#: direction. Flip to MODE_ENFORCING to make an unestablishable required
-#: dimension refuse the command instead of reporting on it.
-CONTAINMENT_MODE = MODE_REPORT_ONLY
+#: Required containment must be established before model-controlled code runs.
+CONTAINMENT_MODE = MODE_ENFORCING
 
 
 # ── Dimensions ──────────────────────────────────────────────────────────────
@@ -296,7 +294,23 @@ class Mechanism:
 
 
 def _bwrap_available() -> bool:
-    return not IS_WINDOWS and bool(shutil.which("bwrap"))
+    if IS_WINDOWS:
+        return False
+    executable = shutil.which("bwrap")
+    if not executable:
+        return False
+    try:
+        # Binary installation says nothing about namespace permissions (notably
+        # under Docker's normal security profile). Only trusted probe code runs.
+        probe = subprocess.run(
+            [executable, "--die-with-parent", "--unshare-pid", "--ro-bind", "/", "/",
+             "--proc", "/proc", "--dev", "/dev", "/bin/true"],
+            stdin=subprocess.DEVNULL, stdout=subprocess.PIPE, stderr=subprocess.PIPE,
+            timeout=3, check=False,
+        )
+        return probe.returncode == 0
+    except (OSError, subprocess.SubprocessError):
+        return False
 
 
 def _posix_group_available() -> bool:
@@ -353,6 +367,7 @@ def _rlimit_dimensions(spec: ContainmentSpec) -> set[str]:
         provided.add(MEMORY)
     if (
         spec.max_processes is not None
+        and os.geteuid() != 0  # RLIMIT_NPROC does not limit root.
         and _rlimit_fits("RLIMIT_NPROC", spec.max_processes)
     ):
         provided.add(PROCESS_COUNT)
@@ -361,7 +376,7 @@ def _rlimit_dimensions(spec: ContainmentSpec) -> set[str]:
 
 def _bwrap_provides(spec: ContainmentSpec) -> frozenset[str]:
     # bwrap gives the private root and the workspace bind (filesystem), a new
-    # session plus --die-with-parent (process_tree), and --unshare-net when the
+    # PID namespace plus --die-with-parent (process_tree), and --unshare-net when the
     # spec asked for no network. The wall clock and the resource limits are
     # ours either way, applied to the bwrap process itself so its descendants
     # inherit them.
@@ -372,16 +387,15 @@ def _bwrap_provides(spec: ContainmentSpec) -> frozenset[str]:
 
 
 def _posix_group_provides(spec: ContainmentSpec) -> frozenset[str]:
-    # A process group plus setsid makes the kill authoritative and the wall
-    # clock real for the whole tree. It says nothing about the filesystem: a
-    # cwd is not a boundary.
-    return frozenset({PROCESS_TREE, WALL_CLOCK} | _rlimit_dimensions(spec))
+    # Groups support escalating teardown, but a descendant can call setsid()
+    # and escape. They cannot truthfully establish process-tree containment.
+    return frozenset({WALL_CLOCK} | _rlimit_dimensions(spec))
 
 
 def _windows_provides(spec: ContainmentSpec) -> frozenset[str]:
-    # taskkill /T /F walks the child tree, which is the Windows equivalent of
-    # signalling a group. There is no setrlimit and no namespace.
-    return frozenset({PROCESS_TREE, WALL_CLOCK})
+    # taskkill supports teardown, but is not a Job Object preventing escaped
+    # descendants. No filesystem or process-tree containment is established.
+    return frozenset({WALL_CLOCK})
 
 
 #: Strongest first. Selection walks this in order and stops at the first
@@ -447,7 +461,7 @@ def _write_record(grant: ContainmentGrant) -> None:
         "id": grant.id,
         "owner": grant.owner,
         "manager_pid": os.getpid(),
-        "manager_token": process_ownership.start_token(os.getpid()),
+        "manager_token": process_ownership.capture(os.getpid())["start_token"],
         "mechanism": grant.mechanism,
         "mode": grant.mode,
         "workspace": grant.workspace,
@@ -784,13 +798,16 @@ def unavailable_tool_result(exc: ContainmentUnavailable, *, tool: str) -> dict[s
 
 
 # ── Launch plumbing ─────────────────────────────────────────────────────────
-def _dir_chain(path: str) -> list[str]:
+def _dir_chain(path: str, mounted: tuple[str, ...] = ()) -> list[str]:
     """``--dir`` args for every ancestor of ``path`` inside the private root.
 
     bwrap mounts into a tmpfs root, so the destination's parents have to exist
     before the bind. Stops at the mount points the argv already creates.
     """
     args: list[str] = []
+    roots = ("/usr", "/etc", *mounted)
+    if any(path == root or path.startswith(root + os.sep) for root in roots):
+        return args
     parents: list[str] = []
     parent = os.path.dirname(path)
     while parent not in ("/", "", "/tmp", "/etc", "/usr", WORKSPACE_MOUNT):
@@ -811,7 +828,7 @@ def _bwrap_prefix(spec: ContainmentSpec) -> list[str]:
     workspace is named by the spec, as ``readonly_extra`` or ``writable_extra``.
     """
     args = [
-        "bwrap", "--die-with-parent", "--new-session",
+        "bwrap", "--die-with-parent", "--new-session", "--unshare-pid",
         "--tmpfs", "/",
         "--dir", "/usr", "--ro-bind", "/usr", "/usr",
         "--symlink", "usr/bin", "/bin",
@@ -820,21 +837,22 @@ def _bwrap_prefix(spec: ContainmentSpec) -> list[str]:
         "--symlink", "usr/bin", "/sbin",
         "--dir", "/etc", "--ro-bind", "/etc", "/etc",
         "--dir", "/tmp", "--tmpfs", "/tmp",
-        "--dev-bind", "/dev", "/dev", "--proc", "/proc",
-        "--dir", WORKSPACE_MOUNT, "--bind", spec.workspace, WORKSPACE_MOUNT,
+        "--dev", "/dev", "--proc", "/proc",
     ]
+    mounted: tuple[str, ...] = ()
+    for flag, paths in (("--ro-bind", spec.readonly_extra), ("--bind", spec.writable_extra)):
+        for path in sorted(paths, key=lambda value: (value.count(os.sep), value)):
+            args.extend(_dir_chain(path, mounted))
+            args.extend((flag, path, path))
+            mounted += (path,)
+    # Mount workspace last so a read-only ancestor never hides its writable bind.
+    args.extend(("--dir", WORKSPACE_MOUNT, "--bind", spec.workspace, WORKSPACE_MOUNT))
     # Preserve absolute workspace paths in generated scripts without exposing
     # a writable parent directory.
     workspace = os.path.realpath(spec.workspace)
     if workspace not in _RESERVED_BIND_DESTS and workspace not in {"/usr", "/etc"}:
-        args.extend(_dir_chain(workspace))
+        args.extend(_dir_chain(workspace, mounted))
         args.extend(("--bind", workspace, workspace))
-    for path in spec.readonly_extra:
-        args.extend(_dir_chain(path))
-        args.extend(("--ro-bind", path, path))
-    for path in spec.writable_extra:
-        args.extend(_dir_chain(path))
-        args.extend(("--bind", path, path))
     if spec.network == NETWORK_NONE:
         args.append("--unshare-net")
     args.extend(("--chdir", WORKSPACE_MOUNT))
@@ -871,7 +889,8 @@ def _rlimit_preexec(grant: ContainmentGrant) -> Optional[Callable[[], None]]:
     return _apply
 
 
-def _launch_argv(grant: ContainmentGrant, command: Any, *, argv: bool) -> list[str]:
+def _launch_argv(grant: ContainmentGrant, command: Any, *, argv: bool,
+                 ready_marker: Optional[str] = None) -> list[str]:
     spec = grant.spec
     if argv:
         parts = [str(part) for part in command]
@@ -894,6 +913,13 @@ def _launch_argv(grant: ContainmentGrant, command: Any, *, argv: bool) -> list[s
                 )
             parts = [shell, "-c", text]
     if grant.mechanism == "bubblewrap":
+        if ready_marker is not None:
+            # This trusted wrapper runs only after all bwrap setup succeeds.
+            # A launch-time bind/security failure must not claim containment.
+            parts = ["/bin/sh", "-c",
+                     'printf "%s\\n" "$1"; IFS= read -r ody_ack || exit 125; '
+                     '[ "$ody_ack" = "$1" ] || exit 125; shift; exec "$@"',
+                     "ody-boundary", ready_marker, *parts]
         return _bwrap_prefix(spec) + parts
     return parts
 
@@ -905,8 +931,8 @@ def _spawn_kwargs(grant: ContainmentGrant) -> dict[str, Any]:
         # reach it, and teardown walks the tree with taskkill /T.
         kwargs["creationflags"] = getattr(subprocess, "CREATE_NEW_PROCESS_GROUP", 0x00000200)
         return kwargs
-    # setsid is what makes PROCESS_TREE real: without it a timeout kill reaches
-    # the wrapper shell and nothing it backgrounded.
+    # A separate group makes ordinary tree teardown possible. The PID
+    # namespace, not setsid, prevents descendants from escaping containment.
     kwargs["start_new_session"] = True
     preexec = _rlimit_preexec(grant)
     if preexec is not None:
@@ -978,61 +1004,101 @@ async def run(
             "backend does not own; it cannot be run locally"
         )
     missing = frozenset(grant.spec.required) - frozenset(grant.enforced)
-    if missing and grant.mode == MODE_ENFORCING:
-        raise ContainmentUnavailable(missing, grant.mechanism)
+    mechanism = next((item for item in MECHANISMS if item.name == grant.mechanism), None)
+    provided = mechanism.provides(grant.spec) if mechanism is not None else frozenset()
+    missing |= frozenset(grant.spec.required) - provided
+    overclaimed = frozenset(grant.enforced) - provided
+    if (missing or overclaimed) and grant.mode == MODE_ENFORCING:
+        raise ContainmentUnavailable(missing | overclaimed, grant.mechanism)
 
     spec = grant.spec
-    launch = _launch_argv(grant, command, argv=argv)
+    marker = uuid.uuid4().hex if grant.mechanism == "bubblewrap" else None
     try:
-        proc = await asyncio.create_subprocess_exec(
+        launch = _launch_argv(grant, command, argv=argv, ready_marker=marker)
+        spawning = asyncio.create_task(asyncio.create_subprocess_exec(
             *launch,
-            stdin=asyncio.subprocess.PIPE if stdin is not None else asyncio.subprocess.DEVNULL,
+            stdin=asyncio.subprocess.PIPE if stdin is not None or marker is not None else asyncio.subprocess.DEVNULL,
             stdout=asyncio.subprocess.PIPE,
             stderr=asyncio.subprocess.PIPE,
             cwd=spec.workspace,
             env=dict(spec.env),
             **_spawn_kwargs(grant),
-        )
+        ))
+        try:
+            proc = await asyncio.shield(spawning)
+        except asyncio.CancelledError:
+            # Cancellation must not detach an OS spawn already in progress.
+            # Recover its handle before propagating cancellation to the caller.
+            try:
+                proc = await _complete_cleanup(spawning, propagate_cancel=False)
+            except Exception:
+                release(grant, grace_s=0)
+            else:
+                live = replace(grant, pid=proc.pid, pgid=None if IS_WINDOWS else proc.pid)
+                await _complete_cleanup(_release_awaited(live, proc), propagate_cancel=False)
+            raise
     except BaseException:
-        # Acquisition can precede a failed or cancelled spawn. A grant without
-        # a child must not become a permanent restart orphan.
-        release(grant, grace_s=0)
+        if "proc" not in locals():
+            release(grant, grace_s=0)
         raise
-    from src.agent_runtime.journal import mark_operation_started
-    mark_operation_started("subprocess", pid=proc.pid)
     # start_new_session makes the child its own group leader, so the group id
     # is the child's pid. Captured here rather than at teardown: once the leader
     # exits, getpgid can no longer tell us which group its children are in.
-    pgid = None if IS_WINDOWS else (_pgid_of(proc.pid) or proc.pid)
+    pgid = None if IS_WINDOWS else proc.pid
     live = replace(grant, pid=proc.pid, pgid=pgid)
     # The start token is what makes this record signallable by a *later*
     # process. Without it a restart reaper holds a pid and no way to tell
     # whether the pid is still this child or something the kernel has since
     # handed to a stranger; see src/process_ownership.py.
-    _update_record(
-        grant.id,
-        pid=proc.pid,
-        pgid=pgid,
-        started_at=time.time(),
-        start_token=process_ownership.capture(proc.pid)["start_token"],
-    )
+    try:
+        _update_record(grant.id, pid=proc.pid, pgid=pgid, started_at=time.time(),
+                       start_token=None if marker is not None else process_ownership.capture(proc.pid)["start_token"],
+                       containment_ready=marker is None, execution_started=marker is None)
+        from src.agent_runtime.journal import mark_operation_started
+        mark_operation_started("subprocess", pid=proc.pid)
+    except BaseException:
+        await _complete_cleanup(_release_awaited(live, proc), propagate_cancel=False)
+        raise
 
     out_buf: list[str] = []
     err_buf: list[str] = []
     out_budget = [int(spec.max_output_bytes)]
     err_budget = [int(spec.max_output_bytes)]
     started = time.time()
-    readers = [
-        asyncio.create_task(_drain(proc.stdout, out_buf, out_budget, output_cb)),
-        asyncio.create_task(_drain(proc.stderr, err_buf, err_budget, output_cb)),
-    ]
+    readers = [asyncio.create_task(_drain(proc.stderr, err_buf, err_budget, output_cb))]
+    ready = marker is None
+    execution_started = marker is None
     async def _wait() -> None:
+        nonlocal ready, execution_started
+        if marker is not None:
+            expected = (marker + "\n").encode("ascii")
+            try:
+                receipt = await proc.stdout.readexactly(len(expected))
+            except (asyncio.IncompleteReadError, OSError):
+                receipt = b""
+            if receipt != expected:
+                raise ContainmentUnavailable(spec.required, grant.mechanism)
+            # The trusted child is waiting for acknowledgment, so model code
+            # cannot exit/recycle the leader before we record its identity.
+            _update_record(grant.id, start_token=process_ownership.capture(proc.pid)["start_token"])
+            if hasattr(os, "pidfd_open") and hasattr(signal, "pidfd_send_signal"):
+                try:
+                    proc._ody_pidfd = os.pidfd_open(proc.pid)
+                except OSError:
+                    raise ContainmentUnavailable(spec.required, grant.mechanism) from None
+            ready = True
+            _update_record(grant.id, containment_ready=True, execution_started=True)
+            execution_started = True
+            proc.stdin.write(expected)
+            await proc.stdin.drain()
+        readers.append(asyncio.create_task(_drain(proc.stdout, out_buf, out_budget, output_cb)))
         # Pipe backpressure is execution time too. Feeding a child that never
         # reads stdin must remain inside the same timeout/cancellation scope.
-        if stdin is not None and proc.stdin is not None:
+        if (stdin is not None or marker is not None) and proc.stdin is not None:
             try:
-                proc.stdin.write(stdin)
-                await proc.stdin.drain()
+                if stdin is not None:
+                    proc.stdin.write(stdin)
+                    await proc.stdin.drain()
             except (BrokenPipeError, ConnectionResetError):
                 pass
             finally:
@@ -1052,34 +1118,42 @@ async def run(
     progress_task = asyncio.create_task(_progress()) if progress_cb else None
     timed_out = False
     outcome: Optional[ReleaseOutcome] = None
+    async def _finish() -> ReleaseOutcome:
+        try:
+            return await _release_awaited(live, proc)
+        finally:
+            if progress_task is not None:
+                progress_task.cancel()
+                try:
+                    await progress_task
+                except (asyncio.CancelledError, Exception):
+                    pass
+            for task in readers:
+                try:
+                    await asyncio.wait_for(asyncio.shield(task), timeout=1)
+                except (asyncio.TimeoutError, Exception):
+                    out_budget[0] = -1
+                    task.cancel()
+                    await asyncio.gather(task, return_exceptions=True)
+            pidfd = getattr(proc, "_ody_pidfd", None)
+            if pidfd is not None:
+                os.close(pidfd)
     try:
         try:
             await asyncio.wait_for(_wait(), timeout=spec.wall_clock_s)
         except asyncio.TimeoutError:
+            if not ready:
+                raise ContainmentUnavailable(spec.required, grant.mechanism)
             timed_out = True
-            outcome = await _release_awaited(live, proc)
-        except asyncio.CancelledError:
-            await _release_awaited(live, proc)
-            raise
+    except BaseException as exc:
+        exc.containment_established = ready
+        exc.containment_executed = execution_started
+        raise
     finally:
-        if progress_task is not None:
-            progress_task.cancel()
-            try:
-                await progress_task
-            except (asyncio.CancelledError, Exception):
-                pass
-        for task in readers:
-            try:
-                await asyncio.wait_for(task, timeout=1)
-            except (asyncio.TimeoutError, asyncio.CancelledError, Exception):
-                task.cancel()
-
-    if not timed_out:
-        # Even a clean exit goes through teardown: a command that backgrounded
-        # something leaves the group populated, and leaving it running is the
-        # leak this boundary exists to close.
-        outcome = await _release_awaited(live, proc)
-    else:
+        # Clean exit, partial initialization, timeout, and cancellation share
+        # the same teardown. Repeated cancellation cannot skip escalation.
+        outcome = await _complete_cleanup(_finish())
+    if timed_out:
         _update_record(grant.id, timed_out=True)
 
     return ContainmentResult(
@@ -1093,6 +1167,23 @@ async def run(
     )
 
 
+async def _complete_cleanup(awaitable, *, propagate_cancel: bool = True):
+    """Finish ownership cleanup despite further cancellation, then propagate it."""
+    task = asyncio.ensure_future(awaitable)
+    cancelled = False
+    while not task.done():
+        try:
+            await asyncio.shield(task)
+        except asyncio.CancelledError:
+            if task.cancelled():
+                raise
+            cancelled = True
+    result = task.result()
+    if cancelled and propagate_cancel:
+        raise asyncio.CancelledError
+    return result
+
+
 # ── release ─────────────────────────────────────────────────────────────────
 # core.platform_compat.kill_process_tree delegates here as well. Native tools,
 # detached jobs and compatibility callers share escalation and death probes.
@@ -1429,32 +1520,63 @@ async def _release_awaited(
     has entirely exited — turning every timeout into a false "survivors"
     report.
     """
+    writer = getattr(proc, "stdin", None)
+    if writer is not None:
+        writer.close()
+        if hasattr(writer, "wait_closed"):
+            try:
+                await asyncio.wait_for(writer.wait_closed(), timeout=1)
+            except (OSError, asyncio.TimeoutError):
+                pass
     if IS_WINDOWS:
         return release(grant, grace_s=grace_s)
 
     pid, pgid = grant.pid, grant.pgid
-    _signal_tree(pid, pgid, signal.SIGTERM)
+    if grant.mechanism == "bubblewrap" and proc.returncode is not None:
+        # Namespace-owner death already destroyed the namespace. Its numeric
+        # PID/PGID may now be reused; no further signal is necessary or safe.
+        await proc.wait()
+        outcome = _outcome_for(grant, dead=True, escalated=False)
+        _finish_release(grant, outcome)
+        return outcome
+    pidfd = getattr(proc, "_ody_pidfd", None)
+    def gone():
+        if pidfd is not None:
+            return bool(select.select([pidfd], [], [], 0)[0])
+        return _tree_gone(pid, pgid)
+    def send(sig):
+        if pidfd is not None:
+            try:
+                # Killing the bwrap owner destroys its private PID namespace,
+                # including descendants that changed session/group. A pidfd
+                # keeps a recycled numeric PID out of the signal path.
+                signal.pidfd_send_signal(pidfd, sig)
+            except OSError:
+                pass
+        else:
+            _signal_tree(pid, pgid, sig)
+    send(signal.SIGTERM)
     try:
         await asyncio.wait_for(proc.wait(), timeout=max(grace_s, 0.05))
     except (asyncio.TimeoutError, ProcessLookupError):
         pass
     deadline = time.monotonic() + max(grace_s, 0.0)
-    while time.monotonic() < deadline and not _tree_gone(pid, pgid):
+    while time.monotonic() < deadline and not gone():
         await asyncio.sleep(_DEATH_POLL_S)
 
     escalated = False
-    if not _tree_gone(pid, pgid):
+    if not gone():
         escalated = True
-        _signal_tree(pid, pgid, signal.SIGKILL)
+        send(signal.SIGKILL)
         try:
             await asyncio.wait_for(proc.wait(), timeout=1.0)
         except (asyncio.TimeoutError, ProcessLookupError):
             pass
         deadline = time.monotonic() + 1.0
-        while time.monotonic() < deadline and not _tree_gone(pid, pgid):
+        while time.monotonic() < deadline and not gone():
             await asyncio.sleep(_DEATH_POLL_S)
 
-    outcome = _outcome_for(grant, dead=_tree_gone(pid, pgid), escalated=escalated)
+    outcome = _outcome_for(grant, dead=gone(), escalated=escalated)
     _finish_release(grant, outcome)
     return outcome
 

src/containment_worker.py

@@ -60,8 +60,8 @@ async def supervise(payload: dict) -> None:
         output, code = f"background execution failed: {type(exc).__name__}: {exc}\n", 1
         report = {"containment": grant.to_dict(), "teardown": record.get("release") or {"dead": False},
                   "output_truncated": False}
-        report["containment"]["executed"] = bool(record.get("pid"))
-        if not record.get("pid"):
+        report["containment"]["executed"] = bool(record.get("execution_started"))
+        if not record.get("containment_ready"):
             report["containment"].update(contained=False, enforced=[])
         if isinstance(exc, containment.ContainmentUnavailable):
             report.update(containment.unavailable_tool_result(exc, tool="bash"))

src/process_ownership.py

@@ -39,7 +39,7 @@ Token granularity, stated because it bounds the guarantee
 ======== ============================= ===============
 Host     Source                        Resolution
 ======== ============================= ===============
-Linux    ``/proc/<pid>/stat`` field 22 ~10 ms (1 tick)
+Linux    boot ID + stat field 22       ~10 ms (1 tick)
 macOS    ``ps -o lstart=``             1 s
 Windows  ``GetProcessTimes``           100 ns
 ======== ============================= ===============
@@ -145,9 +145,18 @@ def _procfs_token(pid: int) -> Optional[str]:
     _, _, rest = raw.rpartition(")")
     fields = rest.split()
     try:
-        return f"procfs:{fields[_PROC_STAT_STARTTIME_INDEX]}"
+        ticks = fields[_PROC_STAT_STARTTIME_INDEX]
     except IndexError:
         raise InspectionUnavailable(f"/proc/{pid}/stat (unexpected layout)") from None
+    try:
+        boot = (PROC_ROOT / "sys/kernel/random/boot_id").read_text(encoding="ascii").strip()
+    except OSError as exc:
+        raise InspectionUnavailable(f"boot identity ({exc})") from exc
+    if not boot:
+        raise InspectionUnavailable("boot identity (empty)")
+    # A persisted PID/start-tick pair can recur after reboot. Bind it to the
+    # boot as well; older receipts cannot authorize a signal on a new boot.
+    return f"procfs:{boot}:{ticks}"
 
 
 def _ps_token(pid: int) -> Optional[str]:

src/process_reaper.py

@@ -232,15 +232,18 @@ def reap_legacy_agent_tmux() -> Dict[str, Any]:
                 if process_ownership.verify(pid, identities[pid]) != process_ownership.OWNED:
                     continue
                 spec = containment.ContainmentSpec(workspace=os.getcwd(), env={}, wall_clock_s=1,
-                                                   required=frozenset({containment.PROCESS_TREE}))
+                                                   required=frozenset())
                 grant = containment.ContainmentGrant(
                     id=uuid.uuid4().hex[:12], mechanism="process_group", workspace=spec.workspace,
-                    enforced=frozenset({containment.PROCESS_TREE}), degraded=(), unenforced_required=(),
+                    enforced=frozenset(), degraded=(containment.FILESYSTEM, containment.PROCESS_TREE), unenforced_required=(),
                     owner=f"legacy-tmux:{session_id}", mode=containment.MODE_ENFORCING,
                     spec=spec, pid=pid, pgid=containment._pgid_of(pid),
                 )
                 containment._write_record(grant)
                 containment._update_record(grant.id, lifetime="cleanup", start_token=identities[pid])
+                receipt = containment._load_records().get(grant.id, {})
+                if receipt.get("start_token") != identities[pid] or receipt.get("lifetime") != "cleanup":
+                    raise RuntimeError("legacy tmux cleanup receipt was not persisted")
                 tracked.append((grant, identities[pid]))
             dead = True
             for grant, token in tracked:

tests/containment_helpers.py

@@ -14,18 +14,26 @@ def capture_owned_spawn(monkeypatch, tmp_path):
     async def fake_exec(*argv, **kwargs):
         captured.update(argv=argv, kwargs=kwargs, command=argv[-1])
         stdout = asyncio.StreamReader()
+        if "ody-boundary" in argv:
+            stdout.feed_data((argv[argv.index("ody-boundary") + 1] + "\n").encode())
         stdout.feed_data(b"ok")
         stdout.feed_eof()
         stderr = asyncio.StreamReader()
         stderr.feed_eof()
         async def wait():
             return 0
+        async def drain():
+            return None
+        writer = SimpleNamespace(write=lambda data: None, drain=drain,
+                                 close=lambda: captured.update(stdin_closed=True))
         return SimpleNamespace(pid=99999999, stdout=stdout, stderr=stderr,
-                               returncode=0, wait=wait)
+                               stdin=writer, returncode=0, wait=wait)
 
     async def release(*args, **kwargs):
         return containment.ReleaseOutcome(dead=True, escalated=False)
 
     monkeypatch.setattr(asyncio, "create_subprocess_exec", fake_exec)
+    if hasattr(containment.os, "pidfd_open"):
+        monkeypatch.delattr(containment.os, "pidfd_open")
     monkeypatch.setattr(containment, "_release_awaited", release)
     return captured

tests/test_agent_bash_tmux_env.py

@@ -38,7 +38,11 @@ def test_direct_bash_subprocess_has_closed_stdin(monkeypatch, tmp_path):
     result = asyncio.run(subprocess_tools.BashTool().execute("echo ok", {}))
 
     assert result["exit_code"] == 0
-    assert captured["kwargs"]["stdin"] is asyncio.subprocess.DEVNULL
+    if "ody-boundary" in captured["argv"]:
+        assert captured["kwargs"]["stdin"] is asyncio.subprocess.PIPE
+        assert captured["stdin_closed"] is True
+    else:
+        assert captured["kwargs"]["stdin"] is asyncio.subprocess.DEVNULL
     assert not (tmp_path / ".tmp").exists()
 
 

tests/test_containment_contract.py

@@ -349,10 +349,8 @@ def test_the_two_modes_differ_only_in_whether_the_shortfall_refuses(monkeypatch,
     assert frozenset(reported.unenforced_required) == caught.value.missing
 
 
-def test_report_only_is_the_shipped_default():
-    """Pinned deliberately: merging this must not change behaviour on a host
-    without bubblewrap. Flipping it is a one-line diff, reviewed as one."""
-    assert containment.CONTAINMENT_MODE == containment.MODE_REPORT_ONLY
+def test_enforcement_is_the_shipped_default():
+    assert containment.CONTAINMENT_MODE == containment.MODE_ENFORCING
 
 
 # ── Spec validation: caller bugs raise in both modes ────────────────────────

tests/test_containment_enforcement.py

@@ -0,0 +1,276 @@
+"""Final enforcement gate: real namespaces, no fallback, and owned cancellation."""
+import asyncio
+import os
+import subprocess
+import sys
+from dataclasses import replace
+
+import pytest
+
+from src import containment, tool_execution
+from src.agent_tools import subprocess_tools
+
+
+@pytest.fixture
+def workspace(tmp_path, monkeypatch):
+    path = tmp_path / "workspace"
+    path.mkdir()
+    monkeypatch.setattr(tool_execution, "agent_cwd", lambda: str(path))
+    monkeypatch.setattr(containment, "_store_path", lambda: tmp_path / "grants.json")
+    return path
+
+
+@pytest.fixture
+def namespaces(workspace):
+    if not containment._bwrap_available():
+        pytest.skip("functional bubblewrap PID/mount namespaces unavailable")
+    return workspace
+
+
+def test_installed_but_nonfunctional_bwrap_is_not_available(monkeypatch):
+    calls = []
+    monkeypatch.setattr(containment, "IS_WINDOWS", False)
+    monkeypatch.setattr(containment.shutil, "which", lambda name: "/usr/bin/bwrap")
+    def blocked(argv, **kwargs):
+        calls.append((argv, kwargs))
+        return subprocess.CompletedProcess(argv, 1, b"", b"Operation not permitted")
+    monkeypatch.setattr(containment.subprocess, "run", blocked)
+    assert containment._bwrap_available() is False
+    assert calls[0][0][-1] == "/bin/true"
+    assert "--unshare-pid" in calls[0][0]
+
+
+@pytest.mark.parametrize("tool,source", [
+    (subprocess_tools.BashTool, "echo forbidden"),
+    (subprocess_tools.PythonTool, "print(1 + 1)"),
+])
+async def test_shipped_mode_refuses_without_namespaces(tool, source, workspace, monkeypatch):
+    assert containment.CONTAINMENT_MODE == containment.MODE_ENFORCING
+    monkeypatch.setattr(containment, "MECHANISMS", tuple(
+        item for item in containment.MECHANISMS if item.name != "bubblewrap"
+    ))
+    async def forbidden(*args, **kwargs):
+        pytest.fail("uncontained model command spawned")
+    monkeypatch.setattr(asyncio, "create_subprocess_exec", forbidden)
+    result = await tool().execute(source, {})
+    assert "containment unavailable" in result["error"]
+    assert result["containment"]["executed"] is False
+    assert result["containment"]["contained"] is False
+    assert {"filesystem", "process_tree"} <= set(result["containment"]["unenforced_required"])
+
+
+def test_process_groups_and_taskkill_do_not_claim_tree_containment(workspace):
+    spec = containment.agent_spec(str(workspace), dict(os.environ), 5)
+    assert containment.PROCESS_TREE not in containment._posix_group_provides(spec)
+    assert containment.PROCESS_TREE not in containment._windows_provides(spec)
+
+
+async def test_fully_overclaimed_group_grant_cannot_spawn(workspace, monkeypatch):
+    spec = containment.agent_spec(str(workspace), {}, 5)
+    forged = containment.ContainmentGrant(
+        id="forged-all", mechanism="process_group", workspace=str(workspace),
+        enforced=containment.DEFAULT_REQUIRED, degraded=(), unenforced_required=(),
+        owner="test", mode=containment.MODE_ENFORCING, spec=spec,
+    )
+    async def forbidden(*args, **kwargs):
+        pytest.fail("overclaimed grant reached a host spawn")
+    monkeypatch.setattr(asyncio, "create_subprocess_exec", forbidden)
+    with pytest.raises(containment.ContainmentUnavailable):
+        await containment.run(forged, "echo forbidden")
+
+
+def test_home_interpreter_is_bound_read_only(workspace, monkeypatch):
+    monkeypatch.setattr(sys, "prefix", "/home/test/venv")
+    spec = subprocess_tools._owned_spec(str(workspace), {}, 5)
+    assert "/home/test/venv" in spec.readonly_extra
+    argv = containment._bwrap_prefix(spec)
+    index = argv.index("/home/test/venv")
+    assert argv[index - 1] == "--ro-bind"
+    assert "--unshare-pid" in argv
+    assert "--dev-bind" not in argv
+    assert "--unshare-net" not in argv
+
+
+async def test_actual_namespace_hides_host_pid_tree_and_sibling(namespaces):
+    sibling = namespaces.parent / "host-secret.txt"
+    sibling.write_text("original")
+    host_namespace = os.readlink("/proc/self/ns/pid")
+    result = await subprocess_tools.PythonTool().execute(
+        "import os\n"
+        "print(os.readlink('/proc/self/ns/pid'))\n"
+        f"print(os.path.exists({str(sibling)!r}))\n"
+        f"try:\n open({str(sibling)!r}, 'w').write('changed')\n"
+        "except OSError:\n pass\n", {},
+    )
+    assert result["exit_code"] == 0, result
+    lines = result["output"].splitlines()
+    assert lines[0] != host_namespace
+    assert lines[1] == "False"
+    assert sibling.read_text() == "original"
+    assert result["containment"]["contained"] is True
+    assert result["teardown"]["dead"] is True
+
+
+async def test_default_namespace_preserves_loopback_sidecars(namespaces):
+    async def reply(reader, writer):
+        writer.write(b"sidecar\n")
+        await writer.drain()
+        writer.close()
+        await writer.wait_closed()
+    server = await asyncio.start_server(reply, "127.0.0.1", 0)
+    async with server:
+        port = server.sockets[0].getsockname()[1]
+        result = await subprocess_tools.PythonTool().execute(
+            f"import socket\ns=socket.create_connection(('127.0.0.1', {port}), timeout=2)\n"
+            "print(s.recv(100).decode().strip())\ns.close()", {},
+        )
+    assert result["output"] == "sidecar", result
+    assert result["containment"]["network"] == "inherit"
+    assert "network" not in result["containment"]["enforced"]
+
+
+async def test_namespace_handshake_closes_model_stdin(namespaces):
+    result = await subprocess_tools.BashTool().execute(
+        "if read value; then echo unexpected; else echo closed; fi", {},
+    )
+    assert result["output"] == "closed", result
+    assert result["teardown"]["dead"] is True
+
+
+async def test_partial_initialization_reaps_before_model_code_starts(namespaces, monkeypatch):
+    from src.agent_runtime import journal
+    effect = namespaces / "must-not-exist"
+    def fail(*args, **kwargs):
+        raise RuntimeError("initialization failed")
+    monkeypatch.setattr(journal, "mark_operation_started", fail)
+    result = await subprocess_tools.PythonTool().execute(
+        f"open({str(effect)!r}, 'w').write('effect')", {},
+    )
+    assert result["exit_code"] == 1
+    assert result["containment"]["executed"] is False
+    assert result["containment"]["contained"] is False
+    assert not effect.exists()
+    assert containment.active_grants() == []
+
+
+async def test_explicit_network_isolation_is_established_or_refused(namespaces):
+    spec = replace(subprocess_tools._owned_spec(str(namespaces), dict(os.environ), 5),
+                   network=containment.NETWORK_NONE,
+                   required=containment.DEFAULT_REQUIRED | {containment.NETWORK})
+    host_namespace = os.readlink("/proc/self/ns/net")
+    grant = containment.acquire(spec, owner="network-hook")
+    try:
+        result = await containment.run(grant, [sys.executable, "-c",
+            "import os; print(os.readlink('/proc/self/ns/net'))"], argv=True)
+    except containment.ContainmentUnavailable:
+        assert containment.active_grants() == []
+    else:
+        assert result.exit_code == 0
+        assert result.stdout.strip() != host_namespace
+        assert containment.NETWORK in result.grant.enforced
+        assert result.release.dead
+
+
+@pytest.mark.parametrize("exit_parent", [False, True])
+async def test_setsid_daemon_cannot_survive_namespace_death(namespaces, exit_parent):
+    heartbeat = namespaces / "heartbeat"
+    code = (
+        "import os,signal,time\n"
+        "pid=os.fork()\n"
+        "if pid:\n"
+        + (" time.sleep(.2); os._exit(0)\n" if exit_parent else " time.sleep(60); os._exit(0)\n")
+        + "os.setsid()\nsignal.signal(signal.SIGTERM, signal.SIG_IGN)\n"
+        "while True:\n"
+        f" open({str(heartbeat)!r}, 'w').write(str(time.monotonic_ns()))\n"
+        " time.sleep(.01)\n"
+    )
+    spec = subprocess_tools._owned_spec(str(namespaces), dict(os.environ), 1)
+    result = await containment.run(containment.acquire(spec, owner="setsid"),
+                                   [sys.executable, "-c", code], argv=True)
+    assert heartbeat.exists(), result.stderr
+    assert result.timed_out is (not exit_parent)
+    assert result.release.dead is True
+    last = heartbeat.read_text()
+    await asyncio.sleep(.15)
+    assert heartbeat.read_text() == last
+    assert containment.active_grants() == []
+
+
+async def test_failed_namespace_initialization_does_not_claim_containment(workspace, monkeypatch):
+    from types import SimpleNamespace
+    monkeypatch.setattr(containment, "MECHANISMS", (containment.Mechanism(
+        "bubblewrap", 30, lambda: True, lambda spec: containment.DEFAULT_REQUIRED,
+    ),))
+    async def fail(*args, **kwargs):
+        stdout, stderr = asyncio.StreamReader(), asyncio.StreamReader()
+        stdout.feed_eof()
+        stderr.feed_data(b"bwrap: bind failed\n")
+        stderr.feed_eof()
+        async def wait():
+            return 1
+        return SimpleNamespace(pid=99999999, stdout=stdout, stderr=stderr, returncode=1, wait=wait)
+    async def release(grant, proc, **kwargs):
+        outcome = containment.ReleaseOutcome(dead=True, escalated=False)
+        containment._finish_release(grant, outcome)
+        return outcome
+    monkeypatch.setattr(asyncio, "create_subprocess_exec", fail)
+    monkeypatch.setattr(containment, "_release_awaited", release)
+    result = await subprocess_tools.PythonTool().execute("print('never')", {})
+    assert "containment unavailable" in result["error"]
+    assert result["containment"]["executed"] is False
+    assert result["containment"]["enforced"] == []
+    assert containment.active_grants() == []
+
+
+@pytest.mark.skipif(os.name == "nt", reason="real POSIX process")
+async def test_cancellation_during_spawn_recovers_and_reaps_handle(workspace, monkeypatch):
+    monkeypatch.setattr(containment, "MECHANISMS", tuple(
+        item for item in containment.MECHANISMS if item.name == "process_group"
+    ))
+    real_spawn = asyncio.create_subprocess_exec
+    spawned, return_handle = asyncio.Event(), asyncio.Event()
+    children = []
+    async def delayed_spawn(*args, **kwargs):
+        proc = await real_spawn(*args, **kwargs)
+        children.append(proc)
+        spawned.set()
+        await return_handle.wait()
+        return proc
+    monkeypatch.setattr(asyncio, "create_subprocess_exec", delayed_spawn)
+    spec = containment.ContainmentSpec(str(workspace), dict(os.environ), 10,
+                                      required={containment.WALL_CLOCK})
+    task = asyncio.create_task(containment.run(containment.acquire(spec, owner="spawn-cancel"),
+        [sys.executable, "-c", "import time; time.sleep(60)"], argv=True))
+    await asyncio.wait_for(spawned.wait(), 3)
+    task.cancel()
+    await asyncio.sleep(.01)
+    task.cancel()
+    return_handle.set()
+    with pytest.raises(asyncio.CancelledError):
+        await asyncio.wait_for(task, 8)
+    assert children[0].returncode is not None
+    assert containment.active_grants() == []
+
+
+@pytest.mark.skipif(os.name == "nt", reason="real POSIX process")
+async def test_repeated_cancellation_cannot_interrupt_kill_escalation(workspace, monkeypatch):
+    monkeypatch.setattr(containment, "MECHANISMS", tuple(
+        item for item in containment.MECHANISMS if item.name == "process_group"
+    ))
+    ready = workspace / "ready"
+    spec = containment.ContainmentSpec(str(workspace), dict(os.environ), 10,
+                                      required={containment.WALL_CLOCK})
+    task = asyncio.create_task(containment.run(containment.acquire(spec, owner="cancel"),
+        [sys.executable, "-c", "import signal,time; signal.signal(signal.SIGTERM,signal.SIG_IGN); "
+         f"open({str(ready)!r},'w').write('ready'); time.sleep(60)"], argv=True))
+    for _ in range(100):
+        if ready.exists():
+            break
+        await asyncio.sleep(.02)
+    assert ready.exists()
+    task.cancel()
+    await asyncio.sleep(.1)
+    task.cancel()
+    with pytest.raises(asyncio.CancelledError):
+        await asyncio.wait_for(task, 8)
+    assert containment.active_grants() == []

tests/test_containment_process_tree.py

@@ -56,12 +56,12 @@ def workspace(tmp_path):
 
 
 def tree_spec(workspace, **kwargs):
-    """A spec requiring exactly what a process group can give."""
+    """Exercise group teardown without claiming prevention of session escape."""
     kwargs.setdefault("env", {"PATH": "/usr/bin:/bin:/usr/sbin:/sbin"})
     kwargs.setdefault("wall_clock_s", 1)
     return containment.ContainmentSpec(
         workspace=workspace,
-        required=frozenset({containment.PROCESS_TREE, containment.WALL_CLOCK}),
+        required=frozenset({containment.WALL_CLOCK}),
         **kwargs,
     )
 
@@ -312,7 +312,7 @@ async def test_a_process_count_limit_is_applied_to_the_child(workspace):
         env={"PATH": "/usr/bin:/bin"},
         wall_clock_s=10,
         required=frozenset({
-            containment.PROCESS_TREE, containment.WALL_CLOCK, containment.PROCESS_COUNT,
+            containment.WALL_CLOCK, containment.PROCESS_COUNT,
         }),
         max_processes=64,
     )
@@ -341,7 +341,7 @@ async def test_a_memory_limit_is_claimed_only_where_it_can_be_applied(workspace)
         workspace=workspace,
         env={"PATH": "/usr/bin:/bin"},
         wall_clock_s=10,
-        required=frozenset({containment.PROCESS_TREE, containment.WALL_CLOCK}),
+        required=frozenset({containment.WALL_CLOCK}),
         max_memory_bytes=limit,
     )
     grant = containment.acquire(spec, owner="session-9")
@@ -369,7 +369,7 @@ def test_an_unenforceable_required_limit_refuses_instead_of_crashing_the_spawn(w
         env={"PATH": "/usr/bin:/bin"},
         wall_clock_s=10,
         required=frozenset({
-            containment.PROCESS_TREE, containment.WALL_CLOCK, containment.MEMORY,
+            containment.WALL_CLOCK, containment.MEMORY,
         }),
         max_memory_bytes=2 * 1024 * 1024 * 1024,
     )

tests/test_execution_filesystem_boundary.py

@@ -53,13 +53,16 @@ def _argv(workspace, **kwargs):
     import shutil as _shutil
 
     original = _shutil.which
+    original_available = containment._bwrap_available
     try:
+        containment._bwrap_available = lambda: True
         _shutil.which = lambda name, *a, **kw: (
             "/usr/bin/bwrap" if name == "bwrap" else original(name, *a, **kw)
         )
         wrapped = subprocess_tools._wrap_workspace_namespace("true", workspace, **kwargs)
     finally:
         _shutil.which = original
+        containment._bwrap_available = original_available
     assert wrapped is not None, "forced bwrap should produce a namespace argv"
     return shlex.split(wrapped)
 
@@ -174,6 +177,7 @@ def test_fallback_reports_that_filesystem_containment_did_not_hold(
 def test_the_fallback_mechanism_is_not_named_like_a_mechanism(workspace, monkeypatch):
     """A string rewrite reported as "bubblewrap" or "none" is the same silence
     with extra steps. It gets its own name so a reader cannot mistake it."""
+    monkeypatch.setattr(containment, "CONTAINMENT_MODE", containment.MODE_REPORT_ONLY)
     monkeypatch.setattr(
         subprocess_tools, "_wrap_workspace_namespace",
         lambda *args, **kwargs: None,

tests/test_native_execution_containment.py

@@ -29,8 +29,8 @@ async def test_native_bash_owns_and_releases_its_child(native_boundary):
     assert result["output"] == "captured"
     assert result["exit_code"] == 0
     assert result["teardown"]["dead"] is True
-    assert result["containment"]["enforced"] == ["process_tree", "wall_clock"]
-    assert result["containment"]["unenforced_required"] == ["filesystem"]
+    assert result["containment"]["enforced"] == ["wall_clock"]
+    assert result["containment"]["unenforced_required"] == ["filesystem", "process_tree"]
     assert result["containment"]["network"] == "inherit"
     assert containment.active_grants() == []
 
@@ -42,7 +42,7 @@ async def test_native_bash_refuses_before_spawn_when_required_boundary_missing(m
     monkeypatch.setattr(asyncio, "create_subprocess_exec", forbidden)
     result = await subprocess_tools.BashTool().execute("echo hello", {})
     assert result["containment"]["executed"] is False
-    assert result["containment"]["unenforced_required"] == ["filesystem"]
+    assert result["containment"]["unenforced_required"] == ["filesystem", "process_tree"]
 
 
 async def test_failed_spawn_releases_unstarted_grant(native_boundary, monkeypatch):

tests/test_process_ownership.py

@@ -217,11 +217,17 @@ def test_the_procfs_token_reads_a_comm_containing_spaces_and_parens(monkeypatch,
     # each value equals its own field number.
     fields = " ".join(str(index) for index in range(4, 54))
     (procfs / "77" / "stat").write_text(f"77 (my (weird) prog) S {fields}\n")
+    boot_path = procfs / "sys/kernel/random/boot_id"
+    boot_path.parent.mkdir(parents=True)
+    boot_path.write_text("first-boot\n")
     monkeypatch.setattr(platform_compat, "PROC_ROOT", procfs)
     monkeypatch.setattr(po, "PROC_ROOT", procfs)
     monkeypatch.setattr(po, "IS_WINDOWS", False)
 
-    assert po.start_token(77) == "procfs:22"
+    assert po.start_token(77) == "procfs:first-boot:22"
+    token = po.start_token(77)
+    boot_path.write_text("second-boot\n")
+    assert po.start_token(77) != token
 
 
 # ── The process tree ────────────────────────────────────────────────────────

tests/test_workspace_artifact_tool_floor.py

@@ -2198,8 +2198,9 @@ def test_python_loaded_code_sees_virtual_workspace_alias(monkeypatch, tmp_path):
     import venv
     from types import SimpleNamespace
 
-    if not shutil.which("bwrap"):
-        return
+    from src import containment
+    if not containment._bwrap_available():
+        pytest.skip("functional bubblewrap namespaces unavailable")
 
     from pathlib import Path
 
@@ -2238,6 +2239,7 @@ def test_workspace_namespace_mounts_only_a_nested_python_environment(monkeypatch
     from src.agent_tools import subprocess_tools
 
     monkeypatch.setattr(subprocess_tools.shutil, "which", lambda name: "/usr/bin/bwrap")
+    monkeypatch.setattr(subprocess_tools.containment, "_bwrap_available", lambda: True)
     environment = tmp_path / "nested" / "venv"
     environment.mkdir(parents=True)
     (environment / "pyvenv.cfg").write_text("home = /usr/bin\n")
@@ -2259,6 +2261,7 @@ def test_workspace_namespace_rejects_broad_or_symlinked_python_prefixes(monkeypa
     from src.agent_tools import subprocess_tools
 
     monkeypatch.setattr(subprocess_tools.shutil, "which", lambda name: "/usr/bin/bwrap")
+    monkeypatch.setattr(subprocess_tools.containment, "_bwrap_available", lambda: True)
     linked_root = tmp_path / "linked-root"
     linked_root.symlink_to("/", target_is_directory=True)
     # Compared against the argv with no interpreter prefix at all: an unsafe
@@ -2290,6 +2293,7 @@ def test_workspace_namespace_preserves_the_64_bit_dynamic_loader(monkeypatch):
     from src.agent_tools import subprocess_tools
 
     monkeypatch.setattr(subprocess_tools.shutil, "which", lambda name: "/usr/bin/bwrap")
+    monkeypatch.setattr(subprocess_tools.containment, "_bwrap_available", lambda: True)
     command = subprocess_tools._wrap_workspace_namespace("echo ok", "/tmp/workspace")
     assert command is not None
     args = shlex.split(command)

website/configuration-reference.md

@@ -75,7 +75,7 @@ The source tree reads **108** `ODYSSEUS_*` variables: 78 an operator may want to
 | `ODYSSEUS_MAX_VISUAL_EVIDENCE_FRAMES` | `'3'` | `src/agent_loop.py:15361` | How many video frames one tool result may contribute. Clamped to 1-8. |
 | `ODYSSEUS_MAX_VISUAL_EVIDENCE_IMAGES` | `'1'` | `src/agent_loop.py:15329` | How many images one tool result may contribute to the model turn. Clamped to 1-8. |
 | `ODYSSEUS_MCP_ALLOWED_COMMANDS` | `''` | `src/agent_tools/admin_tools.py:140` | Security-relevant. Comma-separated allowlist of MCP launcher basenames the agent may start. Empty by default, and the deny list still wins. |
-| `ODYSSEUS_PYTHON_TOOL_SITE_PACKAGES` | `''` | `src/agent_tools/subprocess_tools.py:857` (+1 more) | Security-relevant. Absolute package roots, separated by the platform path separator, exposed to the sandboxed Python tool. Empty exposes none. |
+| `ODYSSEUS_PYTHON_TOOL_SITE_PACKAGES` | `''` | `src/agent_tools/subprocess_tools.py:835` (+1 more) | Security-relevant. Absolute package roots, separated by the platform path separator, exposed to the sandboxed Python tool. Empty exposes none. |
 | `ODYSSEUS_SCRIPT_HOST` | `'localhost'` | `src/builtin_actions.py:919` | Default host for the run-script action. `localhost`, `127.0.0.1`, `local` and empty run locally; any other value runs over SSH. |
 | `ODYSSEUS_TOOL_APPROVAL_GATE` | `'0'` | `src/tool_capabilities.py:645` | Security-relevant. Truthy makes tool calls pass through the approval gate. Off by default. |