fix(reset): refuse every registration during a reset and purge only ids owned by the row's folder (#78)

Review round 2 (codex):
- R1: register_job reads .mam/reset-in-progress under the registry lock and
  refuses while a reset of the workspace owning <ws>/.mam/jobs is live, so the
  public registry.py register CLI and the API no longer bypass the gate. The
  reset's precheck takes that lock once after publishing its marker, so a
  registration is either seen by it or refused. The reset's own create passes
  MAM_RESET_OWNER_PID; the remote runner refuses the dispatch.
- R2: before each purge the reset re-runs stop's revalidate check
  (verify_session_uuid) for a post-discovered id against the row's folder and
  skips the target (id not verified) when it does not verify.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.agents/skills/lib_py/delegation/registry.py

@@ -16,6 +16,8 @@ from __future__ import annotations
 import argparse
 import json
 import logging
+import os
+import subprocess
 import sys
 import uuid
 from pathlib import Path
@@ -65,6 +67,57 @@ def liveness_window(heartbeat_sec: int, heartbeat_misses: int) -> int:
     return max(1, int(heartbeat_sec)) * max(1, int(heartbeat_misses))
 
 
+# Issue #78: a reset of a workspace purges its agents' conversations, so no job
+# may be registered in that workspace's .mam/jobs while one runs. The reset
+# publishes .mam/reset-in-progress (pid/lstart, loop_lock.sh's format) and then
+# takes this registry's lock once before it lists the open jobs; the marker is
+# read under the same lock here, so a registration either is written before
+# that listing or sees the marker. The reset's own create (the onboarding job
+# of an agent it recreates) passes the reset's pid in MAM_RESET_OWNER_PID.
+RESET_OWNER_ENV = "MAM_RESET_OWNER_PID"
+
+
+class ResetInProgressError(RuntimeError):
+    pass
+
+
+def _lstart(pid: str) -> str:
+    try:
+        out = subprocess.run(["ps", "-p", pid, "-o", "lstart="], capture_output=True, text=True,
+                             timeout=10).stdout
+    except (OSError, subprocess.SubprocessError):
+        return ""
+    return " ".join(out.split())
+
+
+def reset_refusal(registry_dir: str) -> Optional[str]:
+    """Why a registration in ``registry_dir`` is refused, or None: a live
+    reset of the workspace that owns it (``<ws>/.mam/jobs``) that is not the
+    caller's own. Holder states as loop_lock.sh decides them: a dead or
+    reused pid is stale; ps failing on this process is unknown (refused)."""
+    jobs = os.path.abspath(registry_dir)
+    if os.path.basename(jobs) != "jobs" or os.path.basename(os.path.dirname(jobs)) != ".mam":
+        return None
+    marker = os.path.join(os.path.dirname(jobs), "reset-in-progress")
+    try:
+        with open(marker, encoding="utf-8") as fh:
+            fields = dict(line.split("=", 1) for line in fh.read().splitlines() if "=" in line)
+    except FileNotFoundError:
+        return None
+    except (OSError, ValueError) as exc:
+        return "the reset marker %s cannot be read (%s)" % (marker, exc)
+    pid = fields.get("pid", "")
+    if not pid.isdigit() or os.environ.get(RESET_OWNER_ENV) == pid:
+        return None
+    if not _lstart(str(os.getpid())):
+        return "cannot tell whether the reset in %s (pid %s) is live (ps unavailable?)" % (marker, pid)
+    cur = _lstart(pid)
+    if not cur or (fields.get("lstart") and cur != fields["lstart"]):
+        return None
+    return ("a reset of %s is in progress (pid %s); its agents are being purged and recreated;"
+            " register the job when it has finished" % (os.path.dirname(os.path.dirname(jobs)), pid))
+
+
 def register_job(
     prompt: str,
     agent: str = "claude-code",
@@ -160,6 +213,9 @@ def register_job(
     if dry_run:
         record["dry_run"] = True
     with registry_lock(registry_dir):
+        refusal = reset_refusal(registry_dir)
+        if refusal:
+            raise ResetInProgressError(refusal)
         if mqtt_common._job_path(job_id, registry_dir).exists():
             if not supersede_older_attempt:
                 raise FileExistsError(f"job already exists: {job_id}")
@@ -556,6 +612,7 @@ def main(argv: Optional[List[str]] = None) -> int:
         if args.parent_job and not mqtt_common._job_path(args.parent_job, rd).exists():
             print(f"unknown parent job {args.parent_job}", file=sys.stderr)
             return 1
+        try:
             job_id = register_job(
                 prompt=_prompt_from_args(parser, args),
                 agent=args.agent,
@@ -581,6 +638,9 @@ def main(argv: Optional[List[str]] = None) -> int:
                 parent_job=args.parent_job,
                 dry_run=args.dry_run,
             )
+        except ResetInProgressError as exc:
+            print("ERROR: %s" % exc, file=sys.stderr)
+            return 1
         print(job_id)
         return 0
 

.agents/skills/lib_py/delegation/remote.py

@@ -221,6 +221,9 @@ def mirror_job(d: Dict[str, Any], registry_dir: str, session: str) -> Optional[s
     except FileExistsError as exc:  # lost the race to a newer (or equal) attempt under the lock
         logger.warning("refusing dispatch for %s: %s", jid, exc)
         return None
+    except registry.ResetInProgressError as exc:  # Issue #78: this workspace is being reset
+        logger.warning("refusing dispatch for %s: %s", jid, exc)
+        return None
     brief_dir = os.path.join(registry_dir, jid)
     os.makedirs(brief_dir, exist_ok=True)
     with open(os.path.join(brief_dir, "brief.md"), "w", encoding="utf-8") as fh:

.agents/skills/lib_py/reset.py

@@ -22,7 +22,9 @@ from typing import Dict, List, Mapping, Optional, Tuple
 
 from lib_py.agents.base import AGENT_SESSION_ENV, POST_DISCOVERED
 from lib_py.agents.registry import agent_of_row, get_adapter, own_key
+from lib_py.delegation.mqtt_common import registry_lock
 from lib_py.update import open_jobs, row_server
+from lib_py.verify_session import verify_session_uuid
 
 SPEC_VERSION = 1
 SPEC_REL = os.path.join(".mam", "reset-spec.json")
@@ -482,6 +484,24 @@ def target_open_jobs(workspace: str, state: dict, env: Mapping[str, str], sessio
     return out
 
 
+def target_id_owned(state: dict, session_name: str) -> bool:
+    """The row's recorded post-discovered id still verifies (revalidate) as a
+    conversation of the row's cwd - the check stop makes before it keeps such
+    an id. stop's own --purge-conversation also removes an id that no longer
+    verifies (a hand-run orphan cleanup); the reset purges only an owned one.
+    stop looks a pre-assigned id up in the cwd itself, so those pass."""
+    row = _rows_by_name(state).get(session_name)
+    agent = agent_of_row(row) if row else None
+    if not agent:
+        return False
+    if get_adapter(agent).id_lifecycle != POST_DISCOVERED:
+        return True
+    raw = row.get(own_key(agent))
+    own = raw.strip() if isinstance(raw, str) else ""
+    cwd = str((row.get("pane") or {}).get("cwd") or "")
+    return bool(own and cwd and verify_session_uuid(cwd, agent, own, row, mode="revalidate"))
+
+
 # --------------------------------------------------------------------------- D1: entries shell lines
 
 def format_entry_line(entry: dict, row: Optional[dict]) -> str:
@@ -737,6 +757,10 @@ def main(argv: Optional[List[str]] = None) -> int:
     s.add_argument("--workspace", required=True)
     s.add_argument("--session", required=True)
 
+    s = sub.add_parser("id-owned")
+    s.add_argument("--workspace", required=True)
+    s.add_argument("--session", required=True)
+
     s = sub.add_parser("record-id")
     s.add_argument("--workspace", required=True)
     s.add_argument("--session", required=True)
@@ -790,6 +814,12 @@ def main(argv: Optional[List[str]] = None) -> int:
         return 1 if sel["errors"] else 0
 
     if a.cmd == "precheck":
+        # A registration that read no reset marker finishes writing under this
+        # lock before the open jobs are listed (registry.reset_refusal).
+        jobs_dir = os.path.join(ws, ".mam", "jobs")
+        if os.path.isdir(jobs_dir):
+            with registry_lock(jobs_dir):
+                pass
         lines = precheck(ws, state, os.environ)
         for line in lines:
             print(line)
@@ -822,6 +852,9 @@ def main(argv: Optional[List[str]] = None) -> int:
             print(line)
         return 1 if lines else 0
 
+    if a.cmd == "id-owned":
+        return 0 if target_id_owned(state, a.session) else 1
+
     if a.cmd == "record-id":
         try:
             record_old_id(ws, state, a.session)

.agents/skills/multi-agent-mux-delegate-job/registry.md

@@ -141,8 +141,9 @@ $PY scripts/registry.py status --job <id> --set completed          # set status
 $PY scripts/registry.py pick   --agent-session herdr:claude         # claim → running
 ```
 
-Exit codes: `0` ok, `1` not found / bad status, `3` (`pick`) no pending job for
+Exit codes: `0` ok, `1` not found / bad status / (`register`) a reset of the
-that session.
+workspace owning `<ws>/.mam/jobs` is in progress (Issue #78), `3` (`pick`) no
+pending job for that session.
 
 ---
 

.agents/skills/multi-agent-mux-reset/SKILL.md

@@ -23,10 +23,10 @@ bash .agents/skills/multi-agent-mux-reset/scripts/reset.sh --yes [--dry-run]
 | Targets | Every registry row with `status: running` and `realpath(pane.cwd) == realpath(WS)`. Rows with any other status, worktree rows, and `orchestrator_uuids` are skipped and listed with their reason. |
 | Confirmation | `[y/N]` prompt; without a terminal `-y`/`--yes` is required (exits `3` otherwise). `--dry-run` inspects without `--yes` and changes nothing. |
 | Prechecks | Refuses before any change when an open job exists (prints the `registry.py ... close --request cancelled` command), when `.mam/loop-guard-active` or `.mam/update-in-progress` is held, when a target row lacks a valid agent or role, when a running `claude`/`grok` target has no recorded conversation id (the monitor had not pinned one; record it, or stop/purge it by hand first), when `.mam/reset-spec.json` is invalid, or when the caller itself is one of the targets. |
-| Lock & concurrency | Takes the update admission lock exclusively, acquires `.mam/loop-guard-active` and publishes `.mam/reset-in-progress`, then releases the admission lock and runs the prechecks. `run_loop.sh`, `update.sh` and another reset refuse on the loop marker; `multi-agent-mux-delegate-job submit` refuses on the reset marker. |
+| Lock & concurrency | Takes the update admission lock exclusively, acquires `.mam/loop-guard-active` and publishes `.mam/reset-in-progress`, then releases the admission lock and runs the prechecks. `run_loop.sh`, `update.sh` and another reset refuse on the loop marker; every job registration in this workspace's `.mam/jobs` (`multi-agent-mux-delegate-job submit`, `registry.py register`, the registry API) refuses on the reset marker, except the onboarding jobs of the reset's own `create_session.sh`. |
 | Spec file & rerun | Writes `.mam/reset-spec.json` atomically before the first stop/purge and removes it only when all targets reach `done`. Rerunning resumes from the spec file without re-purging already recreated agents (`created` or `done`). |
-| Sequence per target | Sequential (never parallel): ⓪ re-checks that its row still has the spec's agent and herdr server and that no job addressed to it is open, ① normal `stop_session.sh --reason reset` (a post-discovered agent's id is captured onto the row while herdr is live; `status: stopped`), ② checks that the row's id is the one recorded before the stop, ③ `stop_session.sh --reason reset --purge-conversation --yes` (using the row's recorded ID, never a CLI UUID), then `create_session.sh` with the original name, agent, role, `--herdr-session`, and `--herdr-workspace` (onboarding enabled by default). |
+| Sequence per target | Sequential (never parallel): ⓪ re-checks that its row still has the spec's agent and herdr server and that no job addressed to it is open, ① normal `stop_session.sh --reason reset` (a post-discovered agent's id is captured onto the row while herdr is live; `status: stopped`), ② checks that the row's id is the one recorded before the stop and, for a post-discovered agent, that it still verifies as a conversation of the row's folder, ③ `stop_session.sh --reason reset --purge-conversation --yes` (using the row's recorded ID, never a CLI UUID), then `create_session.sh` with the original name, agent, role, `--herdr-session`, and `--herdr-workspace` (onboarding enabled by default). |
-| When skipped (exit 4) | The target is skipped and the reset continues to the next agent when step ⓪ finds a changed row (`row changed`) or an open job (`job open`) - nothing was changed for it -, or when step ② finds no id (`no conversation id recorded`) or an id other than the recorded one (`id not verified`), or step ③ exits `4` (`purge refused`, in-use gate) - it is stopped but resumable (its row keeps its id) and its conversation files are untouched. Rerun once the cause is gone, or resume it. |
+| When skipped (exit 4) | The target is skipped and the reset continues to the next agent when step ⓪ finds a changed row (`row changed`) or an open job (`job open`) - nothing was changed for it -, or when step ② finds no id (`no conversation id recorded`) or an id other than the recorded one or one that does not verify for the row's folder (`id not verified`), or step ③ exits `4` (`purge refused`, in-use gate) - it is stopped but resumable (its row keeps its id) and its conversation files are untouched. Rerun once the cause is gone, or resume it. |
 
 | Exit | Meaning |
 |---|---|
@@ -44,5 +44,5 @@ bash .agents/skills/multi-agent-mux-reset/scripts/reset.sh --yes [--dry-run]
 - **No external process termination**: processes holding conversation files open (reported via `lsof` in `in_use_hints`) are never signalled by MAM; end them yourself when safe, then rerun.
 - **Shared stores preserved**: Grok's shared `memory-v2.db` is left intact during purge; only session rows and per-session files are removed.
 - **Orchestrator hook during reset**: while `.mam/loop-guard-active` is held by the reset, the AGY orchestrator's direct file-edit hook (`loop_delegation_guard.sh`) blocks direct edits until the reset finishes.
-- **Job submissions during a reset**: `multi-agent-mux-delegate-job submit` refuses with `a reset of <WS> is in progress` until the reset ends; submit again afterwards. A job registered for a target by other means after the precheck makes that target `job open` (skipped, not cancelled).
+- **Job submissions during a reset**: `multi-agent-mux-delegate-job submit` and `registry.py register` refuse with `a reset of <WS> is in progress` until the reset ends; submit again afterwards. A record written into `.mam/jobs` by hand for a target after the precheck makes that target `job open` (skipped, not cancelled) if it is there before that target's stop.
 - **Same-type post-discovered ordering**: when resetting multiple post-discovered agents of the same type, the second `create_session.sh` waits up to `MAM_ID_ORDER_WAIT_S` for the first agent's ID to be recorded; if it times out, rerun the reset once the ID is recorded.

.agents/skills/multi-agent-mux-reset/scripts/reset.sh

@@ -92,7 +92,9 @@ _refuse_locked() {
 # The update admission lock is taken exclusively, as update.sh does, while the
 # reset publishes its markers: a delegate submit admitted earlier has written
 # its job record (the precheck below sees it), and one admitted later sees
-# .mam/reset-in-progress and refuses.
+# .mam/reset-in-progress and refuses. Any other registration in .mam/jobs
+# (registry.py register, the delegation API) reads the marker under the
+# registry lock, which the precheck takes before it lists the open jobs.
 mkdir -p "$MAM"
 exec 7>>"$MAM/update-admission.lock"
 case "$("$PY" -m lib_py.pane_lock acquire --fd 7 --wait-env MAM_UPDATE_ADMISSION_WAIT_S)" in
@@ -255,6 +257,11 @@ for target_name in ${ENTRY_NAMES[@]+"${ENTRY_NAMES[@]}"}; do
         SKIPPED_ARGS+=(--skipped "$R_NAME:id_unverified")
         continue
       fi
+      if ! MAM_STATE_JSON="$STATE_JSON" "$PY" -m lib_py.reset id-owned --workspace "$WS" --session "$R_NAME"; then
+        echo "skipped $R_NAME: its recorded id $R_ROW_ID does not verify as a conversation of its folder, so it may be another folder's and nothing is purged; check it, purge it by hand if it is this agent's, and rerun the reset"
+        SKIPPED_ARGS+=(--skipped "$R_NAME:id_unverified")
+        continue
+      fi
 
       echo "reset [$R_NAME]: ${STOP_CMD[*]} --purge-conversation --yes"
       purge_rc=0
@@ -283,7 +290,8 @@ for target_name in ${ENTRY_NAMES[@]+"${ENTRY_NAMES[@]}"}; do
 
     echo "reset [$R_NAME]: ${CREATE_CMD[*]}"
     create_rc=0
-    "${CREATE_CMD[@]}" || create_rc=$?
+    # Its onboarding job is the one registration the reset marker lets through.
+    MAM_RESET_OWNER_PID="$$" "${CREATE_CMD[@]}" || create_rc=$?
     if [ "$create_rc" -ne 0 ]; then
       FAILED_SPEC="$R_NAME:create:$create_rc"
       break

tests/test_issue78_reset.py

@@ -1788,3 +1788,177 @@ def test_mam_reset_admit_refuses_only_a_live_reset(mam_sandbox: Path):
         holder.wait()
     res_stale = admit()
     assert res_stale.returncode == 0, res_stale.stderr
+
+
+def test_registry_cli_is_refused_after_the_target_recheck(mam_sandbox: Path, mock_herdr: Path, mock_agents):
+    """Review round 2 R1 (codex): the documented registry CLI, run by a caller
+    that is not a child of the reset, after the target's open-job re-check and
+    before its stop, is refused by .mam/reset-in-progress and registers nothing;
+    the reset's own create still registers its onboarding job."""
+    import threading
+
+    name = "reviewer-claude-01"
+    _claude_transcript(mam_sandbox, mam_sandbox, UA)
+    _mock_herdr_agent(mock_herdr, name, mam_sandbox, agent="claude")
+    _write_rows(mam_sandbox, [_row(name, "claude", mam_sandbox, own_id=UA)])
+    stop = mam_sandbox / ".agents/skills/multi-agent-mux-stop/scripts/stop_session.sh"
+    original = stop.with_name("stop-original.sh")
+    stop.rename(original)
+    entered, release = mam_sandbox / "stop-entered", mam_sandbox / "stop-release"
+    gate = mam_sandbox / "stop-gate.py"
+    gate.write_text(
+        f"""import os, pathlib, sys, time
+entered = pathlib.Path({str(entered)!r})
+release = pathlib.Path({str(release)!r})
+if not entered.exists():
+    entered.touch()
+    end = time.monotonic() + 60
+    while not release.exists() and time.monotonic() < end:
+        time.sleep(0.02)
+os.execv('/bin/bash', ['bash', {str(original)!r}, *sys.argv[1:]])
+""",
+        encoding="utf-8",
+    )
+    stop.write_text("#!/bin/bash\nexec %s %s \"$@\"\n" % (shlex.quote(sys.executable), shlex.quote(str(gate))))
+    stop.chmod(0o755)
+    jobs_dir = mam_sandbox / ".mam" / "jobs"
+    record: dict = {}
+
+    def writer():
+        try:
+            end = time.monotonic() + 60
+            while not entered.exists() and time.monotonic() < end:
+                time.sleep(0.02)
+            record["marker"] = (mam_sandbox / ".mam" / "reset-in-progress").is_file()
+            before = sorted(p.name for p in jobs_dir.glob("*.json"))
+            registry = mam_sandbox / ".agents/skills/multi-agent-mux-delegate-job/scripts/registry.py"
+            res = subprocess.run(
+                [sys.executable, str(registry), "--registry-dir", str(jobs_dir), "register",
+                 "--prompt", "external concurrent work", "--agent", "claude-code", "--agent-session", "herdr:" + name],
+                capture_output=True, text=True, timeout=30,
+            )
+            record.update(rc=res.returncode, stdout=res.stdout, stderr=res.stderr, before=before,
+                          after=sorted(p.name for p in jobs_dir.glob("*.json")))
+        finally:
+            release.touch()
+
+    worker = threading.Thread(target=writer)
+    worker.start()
+    try:
+        res = _run_reset(mam_sandbox, "--yes")
+    finally:
+        worker.join(timeout=90)
+        _wait_reconcile_idle(mam_sandbox)
+    assert not worker.is_alive()
+    assert record["marker"] is True, record
+    assert record["rc"] == 1, record
+    assert "a reset of %s is in progress" % mam_sandbox in record["stderr"], record
+    assert record["stdout"] == "" and record["after"] == record["before"], record
+    assert res.returncode == 0, res.stdout + res.stderr
+    assert _result_of(res.stdout, name) == "done"
+    onboarding = [json.loads(p.read_text(encoding="utf-8")) for p in jobs_dir.glob("*.json")]
+    assert [j["agent_session"] for j in onboarding] == ["herdr:" + name], onboarding
+
+
+def test_register_job_refuses_only_a_live_reset_not_its_own(mam_sandbox: Path, monkeypatch):
+    from lib_py.delegation import registry
+
+    jobs_dir = str(mam_sandbox / ".mam" / "jobs")
+    marker = mam_sandbox / ".mam" / "reset-in-progress"
+    monkeypatch.delenv(registry.RESET_OWNER_ENV, raising=False)
+    holder = subprocess.Popen(["sleep", "120"])
+    try:
+        _live_marker(marker, holder)
+        with pytest.raises(registry.ResetInProgressError, match="a reset of %s is in progress" % mam_sandbox):
+            registry.register_job(prompt="p", agent_session="herdr:x", registry_dir=jobs_dir)
+        assert not list(Path(jobs_dir).glob("*.json"))
+        # Another control plane's registry is not this workspace's .mam/jobs
+        assert registry.reset_refusal(str(mam_sandbox / "elsewhere")) is None
+        monkeypatch.setenv(registry.RESET_OWNER_ENV, str(holder.pid))
+        assert registry.register_job(prompt="p", agent_session="herdr:x", registry_dir=jobs_dir)
+        monkeypatch.delenv(registry.RESET_OWNER_ENV)
+    finally:
+        holder.kill()
+        holder.wait()
+    assert registry.register_job(prompt="p", agent_session="herdr:x", registry_dir=jobs_dir)
+    assert len(list(Path(jobs_dir).glob("*.json"))) == 2
+
+
+def test_precheck_waits_for_a_registration_holding_the_registry_lock(tmp_path: Path):
+    """R1 lock order: a registration that read no reset marker holds the registry
+    lock until its record is written; the precheck, run after the marker is
+    published, takes that lock before it lists the open jobs, so it sees the job."""
+    import fcntl
+
+    ws = tmp_path / "ws"
+    jobs_dir = ws / ".mam" / "jobs"
+    jobs_dir.mkdir(parents=True)
+    state = {"herdr_sessions": [_row("reviewer-claude-01", "claude", ws, own_id=UA)]}
+    env = dict(os.environ, PYTHONPATH=str(SKILLS), PYTHONDONTWRITEBYTECODE="1", MAM_STATE_JSON=json.dumps(state))
+    env.pop("MAM_JOBS_DIR", None)
+    lock = open(jobs_dir / ".lock", "a")
+    fcntl.flock(lock, fcntl.LOCK_EX)
+    try:
+        proc = subprocess.Popen(
+            [sys.executable, "-m", "lib_py.reset", "precheck", "--workspace", str(ws)],
+            env=env, stdout=subprocess.PIPE, stderr=subprocess.PIPE, text=True,
+        )
+        time.sleep(1.5)
+        assert proc.poll() is None, proc.communicate()
+        (jobs_dir / "job78locked.json").write_text(
+            json.dumps({"job_id": "job78locked", "agent_session": "herdr:reviewer-claude-01", "status": "pending"}),
+            encoding="utf-8",
+        )
+    finally:
+        fcntl.flock(lock, fcntl.LOCK_UN)
+        lock.close()
+    out, err = proc.communicate(timeout=30)
+    assert proc.returncode == 1, out + err
+    assert "job job78locked" in out
+
+
+@pytest.mark.parametrize("artifact_cwd", ["own", "foreign"])
+def test_post_discovered_id_is_purged_only_when_it_verifies_for_its_folder(
+    mam_sandbox: Path, mock_herdr: Path, mock_agents, monkeypatch, artifact_cwd: str
+):
+    """Review round 2 R2 (codex): a recorded codex id whose rollout names another
+    folder is not purged (stop's own unverified-own purge is for a hand-run
+    cleanup); the same rollout naming the row's folder is."""
+    from lib_py.agents.base import DiscoveryContext
+    from lib_py.agents.registry import get_adapter
+
+    foreign = mam_sandbox / "another-workspace"
+    foreign.mkdir()
+    cwd = mam_sandbox if artifact_cwd == "own" else foreign
+    home = mam_sandbox / ".codex"
+    monkeypatch.setenv("CODEX_HOME", str(home))
+    rollout = home / "sessions/2026/10/30" / ("rollout-2026-10-30T00-00-00-%s.jsonl" % UB)
+    rollout.parent.mkdir(parents=True)
+    rollout.write_text(json.dumps({"type": "session_meta", "payload": {"id": UB, "cwd": str(cwd)}}) + "\n")
+    name = "reviewer-codex-01"
+    row = _row(name, "codex", mam_sandbox, own_id=UB)
+    row["session_id_verified"] = False
+    _mock_herdr_agent(mock_herdr, name, mam_sandbox, agent="codex")
+    _write_rows(mam_sandbox, [row])
+    # The CLI delete fails, so the adapter's own fallback removes the rollout
+    codex = mam_sandbox / "bin" / "codex"
+    codex.write_text('#!/bin/bash\nif [ "$1" = delete ]; then exit 1; fi\nexit 0\n')
+    codex.chmod(0o755)
+    ctx = DiscoveryContext(workspace=str(mam_sandbox), agent_name="codex", home_dir=str(mam_sandbox),
+                           row=row, mode="revalidate")
+    assert get_adapter("codex").verify_artifact(UB, ctx) is (artifact_cwd == "own")
+
+    res = _run_reset(mam_sandbox, "--yes")
+    _wait_reconcile_idle(mam_sandbox)
+    if artifact_cwd == "own":
+        assert res.returncode == 0, res.stdout + res.stderr
+        assert _result_of(res.stdout, name) == "done"
+        assert not rollout.exists()
+    else:
+        assert res.returncode == 4, res.stdout + res.stderr
+        assert _result_of(res.stdout, name) == "skipped: id not verified"
+        assert "--purge-conversation --yes" not in res.stdout
+        assert rollout.is_file()
+        kept = _read_rows(mam_sandbox)[name]
+        assert kept["status"] == "stopped" and kept["codex_session_id_own"] == UB
+        assert (mam_sandbox / ".mam" / "reset-spec.json").is_file()