diff --git a/tests/test_issue25_plan_reuse.py b/tests/test_issue25_plan_reuse.py
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+++ b/tests/test_issue25_plan_reuse.py
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+"""Issue #25: a promoted plan is reused only when it is named, and an empty
+plan report is never silent.
+
+Without --plan the runner used to glob the auto-resolved planner's report
+directory for plan-*.md and feed the newest one to the Creator as "the plan
+already agreed on". Both keys are wrong: the directory belongs to a session,
+not to this task, and mtime is checkout order. 47 unrelated plans are committed
+in this repository (P1).
+
+The same review also found that the three --plan-mode reads had no content
+check at all, so an empty planner or refine report silently blanked the plan
+and switched the Creator's prompt (P9-P11).
+
+Every test writes only under tmp_path (Issue #20).
+"""
+
+from __future__ import annotations
+
+import json
+import os
+import subprocess
+import sys
+from pathlib import Path
+
+import pytest
+
+REPO_ROOT = Path(__file__).resolve().parent.parent
+RUNNER_PY = REPO_ROOT / ".agents" / "skills" / "lib_py" / "loop" / "runner.py"
+RUN_LOOP_SH = REPO_ROOT / ".agents" / "skills" / "multi-agent-mux-loop" / "scripts" / "run_loop.sh"
+
+GIT_ID = {"GIT_AUTHOR_NAME": "t", "GIT_AUTHOR_EMAIL": "t@example.invalid",
+          "GIT_COMMITTER_NAME": "t", "GIT_COMMITTER_EMAIL": "t@example.invalid"}
+
+PLANNER = "planner-claude-01"
+CREATOR = "creator-claude-01"
+REVIEWER = "reviewer-claude-01"
+
+OLD_PLAN = "# plan for a completely different issue\n\nOLD-PLAN-MARKER\n"
+NEW_PLAN = "# the plan I actually mean\n\nNAMED-PLAN-MARKER\n"
+PASS_REPORT = "looks fine\n\n[VERDICT: PASS]\n"
+FAIL_REPORT = "line 3 is wrong\n\n[VERDICT: NOT PASS]\n"
+FAIL_ESCALATE = "needs a redesign\n\n[ESCALATE: PLANNER]\n\n[VERDICT: NOT PASS]\n"
+
+SELF_PLAN_PROMPT = "계획서가 존재하지 않으므로"
+EXISTING_PLAN_PROMPT = "이미 수립된"
+CORRECTION_WITH_PLAN = "갱신된 다음 계획서에 입각하여"
+
+
+def _git(cwd: Path, *args: str) -> str:
+    return subprocess.run(["git", "-C", str(cwd), *args], capture_output=True, text=True,
+                          check=True, env={**os.environ, **GIT_ID}).stdout.strip()
+
+
+@pytest.fixture
+def ctl(tmp_path, monkeypatch):
+    """A control root whose planner report directory already holds an unrelated
+    promoted plan - the condition that used to inject it (F1/F3)."""
+    main = tmp_path / "main"
+    main.mkdir()
+    _git(main, "init", "-q")
+    (main / "a.txt").write_text("a\n")
+    _git(main, "add", "a.txt")
+    _git(main, "commit", "-q", "-m", "init")
+
+    stale = main / ".agents" / "reports" / PLANNER / "plan-OLD.md"
+    stale.parent.mkdir(parents=True)
+    stale.write_text(OLD_PLAN, encoding="utf-8")
+    os.utime(stale, (2_000_000_000, 2_000_000_000))  # newest by mtime, by a mile
+
+    for k, v in GIT_ID.items():
+        monkeypatch.setenv(k, v)
+    monkeypatch.setenv("WORKSPACE_ROOT", str(main))
+    monkeypatch.delenv("MAM_REAL_ROOT", raising=False)
+    monkeypatch.setenv("MAM_JOBS_DIR", str(main / ".mam" / "jobs"))
+    monkeypatch.delenv("MAM_LOOP_WORKTREE", raising=False)
+    monkeypatch.delenv("MAM_LOOP_BASE", raising=False)
+    # the planner row is what makes the old glob fire at all (F7)
+    monkeypatch.setenv("MAM_STATE_JSON", json.dumps({"herdr_sessions": [
+        {"name": CREATOR, "agent": "claude", "role": "creator", "status": "running"},
+        {"name": REVIEWER, "agent": "claude", "role": "reviewer", "status": "running"},
+        {"name": PLANNER, "agent": "claude", "role": "planner", "status": "running"},
+    ]}))
+    return main
+
+
+def _runner(*extra):
+    from lib_py.loop import runner as lr
+    return lr.LoopRunner(["--creator", CREATOR, "--task", "t25", *extra])
+
+
+def _drive(monkeypatch, tmp_path, argv, reports=None, on_worker=None, max_loop="1"):
+    """run() end to end with the delegation stubbed.
+
+    `reports` maps (role, nth-call-of-that-role) to the report body; a body of
+    None means the report file is missing. Everything else gets a PASS for a
+    Reviewer and a one-line report otherwise. The existing _drive helpers hand
+    every job the same non-empty PASS report, which cannot reach the empty-plan
+    paths at all (F13).
+
+    Returns (rc, [(role, prompt)], runner).
+    """
+    from lib_py.loop import runner as lr
+    monkeypatch.setattr(lr.signal, "signal", lambda *a, **k: None)
+    r = lr.LoopRunner(["--creator", CREATOR, "--task", "t25",
+                       "--reviewer", REVIEWER, "--max-loop", max_loop, *argv])
+    reports = reports or {}
+    calls, files, nth = [], {}, {}
+    stub_dir = tmp_path / "stub-reports"
+    stub_dir.mkdir(exist_ok=True)
+
+    def fake_delegate(session, agent_type, role, prompt):
+        calls.append((role, prompt))
+        jid = f"j{len(calls)}"
+        n = nth[role] = nth.get(role, 0) + 1
+        body = reports.get((role, n), PASS_REPORT if role == "Reviewer" else "done\n")
+        if body is None:
+            files[jid] = None
+        else:
+            f = stub_dir / f"{jid}.md"
+            f.write_text(body, encoding="utf-8")
+            files[jid] = f
+        if role == "Worker" and on_worker:
+            on_worker(r)
+        return jid
+
+    monkeypatch.setattr(r, "delegate_job", fake_delegate)
+    monkeypatch.setattr(r, "wait_for_job", lambda *a, **k: True)
+    monkeypatch.setattr(r, "find_report", lambda jid: files.get(jid))
+    return r.run(), calls, r
+
+
+def _roles(calls, role):
+    return [p for (ro, p) in calls if ro == role]
+
+
+# ---------------------------------------------------------------------------
+# P1-P2 — reuse is explicit
+# ---------------------------------------------------------------------------
+
+def test_p1_no_options_does_not_inject_an_unrelated_plan(ctl, monkeypatch, tmp_path, capsys):
+    """The #25 reproduction: a running planner plus a promoted plan in its
+    report directory must not reach the Creator. Fails before the fix."""
+    rc, calls, _ = _drive(monkeypatch, tmp_path, [])
+    assert rc == 0
+    worker = _roles(calls, "Worker")[0]
+    assert worker.startswith(SELF_PLAN_PROMPT)
+    assert "OLD-PLAN-MARKER" not in worker
+    assert EXISTING_PLAN_PROMPT not in worker
+    out = capsys.readouterr().out
+    assert "Found existing promoted plan" not in out
+    assert "No plan loaded" in out
+
+
+def test_p2_plan_file_is_the_only_plan_and_lives_one_round(ctl, monkeypatch, tmp_path):
+    """The named plan is used, the newer unrelated one is not, and the plan is
+    not repeated in the correction round (N1/D16 - the behaviour the implicit
+    load had too)."""
+    named = tmp_path / "my-plan.md"
+    named.write_text(NEW_PLAN, encoding="utf-8")
+    rc, calls, _ = _drive(monkeypatch, tmp_path, ["--plan-file", str(named)],
+                          reports={("Reviewer", 1): FAIL_REPORT}, max_loop="2")
+    assert rc == 0
+    workers = _roles(calls, "Worker")
+    assert workers[0].startswith(EXISTING_PLAN_PROMPT)
+    assert "NAMED-PLAN-MARKER" in workers[0]
+    assert "OLD-PLAN-MARKER" not in workers[0]
+
+    assert len(workers) == 2, "a correction round ran"
+    assert "NAMED-PLAN-MARKER" not in workers[1]
+    assert workers[1].startswith("리뷰어들이 지적한 다음 피드백")
+
+
+# ---------------------------------------------------------------------------
+# P3-P5 — the option is checked before any job exists
+# ---------------------------------------------------------------------------
+
+def test_p3_unusable_plan_files_are_refused_before_any_job(ctl, tmp_path, monkeypatch):
+    empty, ws, sub = tmp_path / "empty.md", tmp_path / "ws.md", tmp_path / "sub"
+    empty.write_text("")
+    ws.write_text("   \n\t\n")
+    sub.mkdir()
+    cases = [tmp_path / "nope.md", sub, empty, ws]
+
+    if os.getuid() != 0:
+        locked = tmp_path / "locked.md"
+        locked.write_text(NEW_PLAN, encoding="utf-8")
+        locked.chmod(0o000)
+        cases.append(locked)
+
+    from lib_py.loop import runner as lr
+    for path in cases:
+        r = lr.LoopRunner(["--creator", CREATOR, "--task", "t25", "--plan-file", str(path)])
+        monkeypatch.setattr(r, "delegate_job", lambda *a, **k: pytest.fail("a job was delegated"))
+        with pytest.raises(SystemExit) as e:
+            r.parse_args()
+        assert e.value.code == 1, path
+
+
+def test_p3b_the_refusal_names_the_resolved_path(ctl, tmp_path, capsys):
+    missing = tmp_path / "nope.md"
+    with pytest.raises(SystemExit):
+        _runner("--plan-file", str(missing)).parse_args()
+    assert str(missing.resolve()) in capsys.readouterr().err
+
+
+def test_p4_plan_file_conflicts_with_plan_and_needs_a_value(ctl, tmp_path, monkeypatch):
+    named = tmp_path / "my-plan.md"
+    named.write_text(NEW_PLAN, encoding="utf-8")
+    from lib_py.loop import runner as lr
+    for argv in (["--plan-file", str(named), "--plan"], ["--plan", "--plan-file", str(named)],
+                 ["--plan-file"]):
+        r = lr.LoopRunner(["--creator", CREATOR, "--task", "t25", *argv])
+        monkeypatch.setattr(r, "delegate_job", lambda *a, **k: pytest.fail("a job was delegated"))
+        with pytest.raises(SystemExit) as e:
+            r.parse_args()
+        assert e.value.code == 1, argv
+
+
+def _reviewable_worktree(ctl, tmp_path):
+    """A linked worktree with one commit to review. The source root has to be
+    separate from the control root here: --base turns review identity on, and
+    the loop's own checkpoint under the control root's .mam would otherwise
+    count as the source changing mid-review."""
+    wt = tmp_path / "wt"
+    _git(ctl, "worktree", "add", "-q", "-b", "feat", str(wt))
+    base = _git(wt, "rev-parse", "HEAD")
+    (wt / "a.txt").write_text("a\nimplemented\n")
+    _git(wt, "commit", "-qam", "impl")
+    return ["--worktree", str(wt), "--base", base, "--review-only"]
+
+
+def test_p5_plan_file_is_warned_about_and_ignored_with_review_only(ctl, monkeypatch, tmp_path, capsys):
+    named = tmp_path / "my-plan.md"
+    named.write_text(NEW_PLAN, encoding="utf-8")
+    rc, calls, r = _drive(monkeypatch, tmp_path,
+                          ["--plan-file", str(named), *_reviewable_worktree(ctl, tmp_path)])
+    assert rc == 0
+    assert _roles(calls, "Worker") == [], "Phase 2 is skipped"
+    assert "NAMED-PLAN-MARKER" not in _roles(calls, "Reviewer")[0]
+    assert r.current_plan == ""
+    assert "--plan-file is ignored with --review-only" in capsys.readouterr().out
+
+
+def test_p5b_the_ignore_warning_needs_the_option(ctl, monkeypatch, tmp_path, capsys):
+    """The warning is keyed on the option being given, not on a default value -
+    unlike the --plan-talk warning it sits next to (N2, runner.py:246)."""
+    rc, _, _ = _drive(monkeypatch, tmp_path, _reviewable_worktree(ctl, tmp_path))
+    assert rc == 0
+    assert "is ignored with --review-only" not in capsys.readouterr().out
+
+
+# ---------------------------------------------------------------------------
+# P6, P9-P11 — --plan mode: compatible, and never silently planless
+# ---------------------------------------------------------------------------
+
+def test_p6_plan_mode_still_plans_and_promotes(ctl, monkeypatch, tmp_path):
+    rc, calls, r = _drive(monkeypatch, tmp_path, ["--plan", "--plan-talk", "0"],
+                          reports={("Planner", 1): NEW_PLAN})
+    assert rc == 0
+    worker = _roles(calls, "Worker")[0]
+    assert worker.startswith(EXISTING_PLAN_PROMPT)
+    assert "NAMED-PLAN-MARKER" in worker
+    promoted = ctl / ".agents" / "reports" / PLANNER / f"plan-{r.plan_job_id}.md"
+    assert promoted.is_file() and "NAMED-PLAN-MARKER" in promoted.read_text()
+
+
+@pytest.mark.parametrize("body", ["", "  \n\t\n"], ids=["empty", "whitespace"])
+def test_p9_an_empty_initial_plan_stops_the_run(ctl, monkeypatch, tmp_path, capsys, body):
+    """D13: paying for a planning phase and getting nothing back must not be a
+    quiet demotion to self-planning."""
+    rc, calls, _ = _drive(monkeypatch, tmp_path, ["--plan", "--plan-talk", "0"],
+                          reports={("Planner", 1): body})
+    assert rc == 1
+    assert _roles(calls, "Worker") == [], "no implementation was delegated"
+    assert "has no plan text" in capsys.readouterr().err
+
+
+def test_p10_an_empty_refine_keeps_the_previous_plan(ctl, monkeypatch, tmp_path, capsys):
+    """D14: the discussion turn must not blank a plan that is still good."""
+    rc, calls, _ = _drive(monkeypatch, tmp_path, ["--plan", "--plan-talk", "1"],
+                          reports={("Planner", 1): NEW_PLAN, ("Planner", 2): ""})
+    assert rc == 0
+    worker = _roles(calls, "Worker")[1]  # [0] is the Creator's challenge turn
+    assert worker.startswith(EXISTING_PLAN_PROMPT)
+    assert "NAMED-PLAN-MARKER" in worker
+    assert "keeping the previous plan" in capsys.readouterr().out
+
+
+def test_p11_an_empty_escalation_refine_never_claims_an_empty_plan(ctl, monkeypatch, tmp_path, capsys):
+    """D14/D15: the correction prompt asserts "follow the updated plan below",
+    so the plan it carries must never be blank."""
+    rc, calls, _ = _drive(monkeypatch, tmp_path, ["--plan", "--plan-talk", "0"],
+                          reports={("Planner", 1): NEW_PLAN, ("Planner", 2): "",
+                                   ("Reviewer", 1): FAIL_ESCALATE},
+                          max_loop="2")
+    assert rc == 0
+    correction = _roles(calls, "Worker")[1]
+    assert CORRECTION_WITH_PLAN in correction
+    assert "NAMED-PLAN-MARKER" in correction, "the prompt claims a plan; it must carry one"
+    assert "keeping the previous plan" in capsys.readouterr().out
+
+
+# ---------------------------------------------------------------------------
+# P7-P8 — wrapper parity and the legacy shell path
+# ---------------------------------------------------------------------------
+
+def test_p7_wrapper_and_runner_agree_on_the_option(tmp_path):
+    line = "  --plan-file <path>     Reuse an existing plan file, relative to the control root (not with --plan)"
+    sh = subprocess.run(["bash", str(RUN_LOOP_SH), "--help"], capture_output=True, text=True)
+    assert line in sh.stdout.splitlines()
+
+    code = ("import sys; sys.path.insert(0, %r)\n"
+            "from lib_py.loop import runner as lr\n"
+            "lr.LoopRunner([]).print_usage()\n" % str(REPO_ROOT / ".agents" / "skills"))
+    py = subprocess.run([sys.executable, "-c", code], capture_output=True, text=True)
+    assert line in py.stdout.splitlines()
+
+
+def test_p7b_the_legacy_shell_loop_refuses_the_option(tmp_path):
+    marker = tmp_path / "loop.marker"
+    res = subprocess.run(["bash", str(RUN_LOOP_SH), "--creator", CREATOR, "--task", "t25",
+                          "--plan-file", str(tmp_path / "x.md")],
+                         capture_output=True, text=True, cwd=str(tmp_path),
+                         env={**os.environ, "MAM_LOOP_PY": "0", "MAM_LOOP_MARKER": str(marker)})
+    assert res.returncode == 1
+    assert "--plan-file" in res.stderr
+    assert not marker.exists(), "refused before the loop lock"
+
+
+def test_p8_neither_loop_implementation_globs_for_a_plan_any_more():
+    for path in (RUN_LOOP_SH, RUNNER_PY):
+        assert "plan-*.md" not in path.read_text(encoding="utf-8"), path