feat(soak): 补上 context_overflow 与 env_error 两类，七类变九类

一次 193 个运行的全量跑完之后，停止原因的十个取值里有两个一次都没出现过。没出现不等于
它们是对的，只等于没验过——这正是「全绿要先怀疑负载」该指向的地方。

context_overflow 的判据不能照字面写成「最后一步的提示词超过上限」：规模判定在调模型之前
做，命中时不产生步记录，所以落盘的每条步记录必定不超上限，那样断言等于断言契约的反面。
改成判「再走一步会有多大」，公式拿全量里 865 对相邻步验过，0 处不符。

env_error 是真把容器 docker kill 掉，不是用测试替身。它自己起一个池、用另一个端口——
共用那个 size=1 的池的话，排在它后面的每一类都会跑在一个不存在的环境上。

实跑：两类都通过，击穿 0、无法判定 0。

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

tools/soak/tests/test_faults.py

@@ -21,57 +21,81 @@ import json
 import sys
 from pathlib import Path
 
+import httpx
 import pytest
 
 from polyloop.ports import EventKind, InvalidDecision, RunLog
+from polyloop.session import RunRequest
+from polyloop.tools import ToolRegistry
 from polyloop.types import (
     ActionOutcome,
     ActionStatus,
+    Budget,
+    Context,
+    Injection,
     Intent,
     IntentKind,
+    Message,
     ModelCallResult,
     ModelReply,
     ReplayPolicy,
+    Role,
     RunFinished,
     RunResult,
     RunStarted,
     StepCompleted,
     StepRecord,
     StopReason,
+    TextBlock,
 )
 from tools.soak.faults import (
+    CONTEXT_OVERFLOW_SLACK_CHARS,
     CRASH_EXIT_CODE,
+    FAULT_NAMES,
     AlwaysInvalidParser,
     CallGuard,
     Criterion,
     CriterionStatus,
+    EnvBreakingExecutor,
     FaultReport,
     JsonlEventSink,
     KillTiming,
     LogRead,
     SelfKillingStore,
+    build_context_overflow_budget,
     build_parser,
     check_all_steps_parse_failed,
+    check_at_least_one_step,
     check_audit_unchanged,
     check_cancelled_raised,
     check_crash_prefix_preserved,
+    check_env_broken_after_a_full_step,
     check_env_untouched,
     check_executed_action_count,
     check_intents_settled,
+    check_last_observation_is_synthetic,
+    check_last_step_action_status,
     check_lease_returned,
     check_log_readable,
     check_never_action_not_replayed,
     check_no_env_error_step,
+    check_prompt_chars_monotonic,
+    check_prompt_reached_max_prompt_chars,
     check_resume_made_progress,
+    check_run_finished_present,
     check_step_count,
     check_step_indices_dense,
+    check_steps_before_last_all_executed,
     check_stop_reason,
+    container_name_for_port,
     count_model_calls,
     guarded,
+    initial_prompt_chars,
     main,
     parse_audit_line,
     parse_terminated,
     read_log,
+    should_break_env,
     should_kill,
     spawn_and_kill,
     stop_reason_of,
@@ -79,6 +103,7 @@ from tools.soak.faults import (
     terminated_prefix,
     write_sidecars,
 )
+from tools.soak.scenarios.appworld import build_synthetic_observations
 from tools.soak.scenarios.govdoc import AUDIT_LOG_NAME
 
 RUN_ID = "fault-test-0"
@@ -123,6 +148,10 @@ def step_completed(
     status: str | None = "executed",
     parse_ok: bool = True,
     action_status: str | None = "executed",
+    prompt_chars: object = 10,
+    raw_output: str = "x",
+    observation: str = "o",
+    observation_is_synthetic: bool = False,
 ) -> dict[str, object]:
     outcome = (
         None
@@ -142,16 +171,16 @@ def step_completed(
         "action_outcome": outcome,
         "step": {
             "step_idx": step_idx,
-            "raw_output": "x",
+            "raw_output": raw_output,
-            "content_chars": 1,
+            "content_chars": len(raw_output),
             "thinking_chars": 0,
             "action": None,
             "parse_ok": parse_ok,
             "parse_error": None if parse_ok else "解释不了",
-            "observation": "o",
+            "observation": observation,
-            "observation_is_synthetic": False,
+            "observation_is_synthetic": observation_is_synthetic,
             "observation_truncated_chars": 0,
-            "prompt_chars": 10,
+            "prompt_chars": prompt_chars,
             "call_id": "c0",
             "step_wall_ms": 1,
             "tool_name": None,
@@ -163,6 +192,29 @@ def step_completed(
     }
 
 
+#: 造日志时用的观察模板。套一次观察多出 `len("观察：\n") == 4` 个字符，判据算「再走一步的提示词
+#: 会有多大」时要把这四个字符算进去。
+TEMPLATE = "观察：{observation}\n"
+
+
+def run_started(
+    *, max_prompt_chars: int = 100, observation_template: str = TEMPLATE
+) -> dict[str, object]:
+    """运行开始那条记录。参数快照里只放判据会读的两个键。
+
+    真的快照还有十几个键，多放几个不会让任何一条判据的行为改变——它们按键名取值。
+    """
+    return {
+        "record": "run_started",
+        "run_id": RUN_ID,
+        "parameter_snapshot": {
+            "request.max_prompt_chars": str(max_prompt_chars),
+            "request.observation_template": observation_template,
+        },
+        "schema_version": 1,
+    }
+
+
 def run_finished(*, stop_reason: str = "task_completed") -> dict[str, object]:
     return {
         "record": "run_finished",
@@ -1181,3 +1233,497 @@ def test_parser_accepts_repeated_fault_flags() -> None:
         ]
     )
     assert args.fault == ["cancel_model", "cancel_env"]
+
+
+# ---------------------------------------------------------------------------
+# 十五、撞提示词上限
+# ---------------------------------------------------------------------------
+
+
+def test_run_finished_present_passes_and_breaches() -> None:
+    """结束记录在不在与它带的取值对不对是两条判据，成因不同。"""
+    assert check_run_finished_present(as_read(run_finished())).status is CriterionStatus.PASSED
+    assert check_run_finished_present(as_read(step_completed())).status is CriterionStatus.BREACHED
+
+
+def test_stop_reason_context_overflow_passes_and_breaches() -> None:
+    good = as_read(step_completed(), run_finished(stop_reason="context_overflow"))
+    bad = as_read(step_completed(), run_finished(stop_reason="step_budget"))
+    assert check_stop_reason(good, "context_overflow").status is CriterionStatus.PASSED
+    breach = check_stop_reason(bad, "context_overflow")
+    assert breach.status is CriterionStatus.BREACHED
+    assert "step_budget" in breach.evidence
+
+
+def test_at_least_one_step_passes() -> None:
+    assert check_at_least_one_step(as_read(step_completed())).status is CriterionStatus.PASSED
+
+
+def test_at_least_one_step_is_undetermined_without_steps() -> None:
+    """第一步就撞上限的话这一类什么都没验到，报「无法判定」不报「击穿」。"""
+    outcome = check_at_least_one_step(as_read(run_started(), run_finished()))
+    assert outcome.status is CriterionStatus.UNDETERMINED
+    assert "一条步记录都没有" in outcome.evidence
+
+
+def test_prompt_chars_monotonic_passes() -> None:
+    read = as_read(
+        step_completed(step_idx=0, prompt_chars=100),
+        step_completed(step_idx=1, prompt_chars=100),
+        step_completed(step_idx=2, prompt_chars=250),
+    )
+    outcome = check_prompt_chars_monotonic(read)
+    assert outcome.status is CriterionStatus.PASSED
+    assert "100" in outcome.evidence and "250" in outcome.evidence
+
+
+def test_prompt_chars_monotonic_breaches_on_a_drop() -> None:
+    """一次下降就是历史被截断过——那是这件事在轨迹里唯一看得见的痕迹。"""
+    read = as_read(
+        step_completed(step_idx=0, prompt_chars=100),
+        step_completed(step_idx=1, prompt_chars=300),
+        step_completed(step_idx=2, prompt_chars=120),
+    )
+    outcome = check_prompt_chars_monotonic(read)
+    assert outcome.status is CriterionStatus.BREACHED
+    assert "第 2 步从 300 掉到 120" in outcome.evidence
+
+
+def test_prompt_chars_monotonic_breaches_on_a_non_integer() -> None:
+    read = as_read(step_completed(prompt_chars="很多"))
+    assert check_prompt_chars_monotonic(read).status is CriterionStatus.BREACHED
+
+
+def test_prompt_chars_monotonic_is_undetermined_without_steps() -> None:
+    assert check_prompt_chars_monotonic(as_read(run_started())).status is (
+        CriterionStatus.UNDETERMINED
+    )
+
+
+def test_prompt_reached_max_prompt_chars_passes() -> None:
+    """最后一步自己装得下，再走一步就装不下——那才是「撑到了上限那条线上」。
+
+    上限 100；最后一步的提示词 90，它的输出 5 个字符、观察 10 个字符再加模板的 4 个，
+    下一次装配是 109 字符。
+    """
+    read = as_read(
+        run_started(max_prompt_chars=100),
+        step_completed(prompt_chars=90, raw_output="x" * 5, observation="y" * 10),
+        run_finished(stop_reason="context_overflow"),
+    )
+    outcome = check_prompt_reached_max_prompt_chars(read)
+    assert outcome.status is CriterionStatus.PASSED
+    assert "109" in outcome.evidence
+
+
+def test_prompt_reached_max_prompt_chars_breaches_when_it_still_fits() -> None:
+    """还装得下就报 context_overflow：这次运行根本没撞到上限。"""
+    read = as_read(
+        run_started(max_prompt_chars=100),
+        step_completed(prompt_chars=50, raw_output="x", observation="y"),
+        run_finished(stop_reason="context_overflow"),
+    )
+    outcome = check_prompt_reached_max_prompt_chars(read)
+    assert outcome.status is CriterionStatus.BREACHED
+    assert "仍不超过上限 100" in outcome.evidence
+
+
+def test_prompt_reached_max_prompt_chars_breaches_when_an_oversized_prompt_was_admitted() -> None:
+    """步记录自己的提示词就超了上限，说明有一次超限的装配被放行去调了模型。"""
+    read = as_read(
+        run_started(max_prompt_chars=100),
+        step_completed(prompt_chars=120, raw_output="x", observation="y"),
+        run_finished(stop_reason="context_overflow"),
+    )
+    outcome = check_prompt_reached_max_prompt_chars(read)
+    assert outcome.status is CriterionStatus.BREACHED
+    assert "被放行去调了模型" in outcome.evidence
+
+
+def test_prompt_reached_max_prompt_chars_reads_the_limit_from_the_snapshot() -> None:
+    """上限从参数快照读，不硬编码：同一条步记录换个上限就该翻面。"""
+    step = step_completed(prompt_chars=90, raw_output="x" * 5, observation="y" * 10)
+    tight = as_read(run_started(max_prompt_chars=100), step)
+    loose = as_read(run_started(max_prompt_chars=100_000), step)
+    assert check_prompt_reached_max_prompt_chars(tight).status is CriterionStatus.PASSED
+    assert check_prompt_reached_max_prompt_chars(loose).status is CriterionStatus.BREACHED
+
+
+def test_prompt_reached_max_prompt_chars_is_undetermined_without_run_started() -> None:
+    read = as_read(step_completed(), run_finished(stop_reason="context_overflow"))
+    outcome = check_prompt_reached_max_prompt_chars(read)
+    assert outcome.status is CriterionStatus.UNDETERMINED
+    assert "run_started" in outcome.evidence
+
+
+def test_prompt_reached_max_prompt_chars_is_undetermined_without_steps() -> None:
+    read = as_read(run_started(), run_finished(stop_reason="context_overflow"))
+    assert check_prompt_reached_max_prompt_chars(read).status is CriterionStatus.UNDETERMINED
+
+
+def test_prompt_reached_max_prompt_chars_is_undetermined_on_a_bad_snapshot() -> None:
+    read = as_read(
+        {
+            "record": "run_started",
+            "run_id": RUN_ID,
+            "parameter_snapshot": {
+                "request.max_prompt_chars": "很多",
+                "request.observation_template": TEMPLATE,
+            },
+            "schema_version": 1,
+        },
+        step_completed(),
+    )
+    assert check_prompt_reached_max_prompt_chars(read).status is CriterionStatus.UNDETERMINED
+
+
+# ---------------------------------------------------------------------------
+# 十六、按上下文现算提示词上限
+# ---------------------------------------------------------------------------
+
+
+def a_request(
+    *,
+    run_level: tuple[str, ...] = ("系统段",),
+    goal_level: tuple[str, ...] = ("题面",),
+    injections: dict[str, tuple[Injection, ...]] | None = None,
+) -> RunRequest:
+    """一份只填了装配用得着那几样的请求。执行器是个不派生自注册表的普通对象，构造期不比对。"""
+
+    class _Executor:
+        def parameters(self) -> dict[str, str]:
+            return {"kind": "fake"}
+
+        async def execute(self, action: object) -> ActionOutcome:  # pragma: no cover - 用不到
+            raise AssertionError("这份请求只用来算提示词规模")
+
+    return RunRequest(
+        run_id=RUN_ID,
+        budget=Budget(
+            max_steps=1, max_actions=1, max_consecutive_parse_failures=1, max_prompt_chars=1
+        ),
+        action_executor=_Executor(),  # type: ignore[arg-type]
+        tools=ToolRegistry(),
+        context=Context(
+            run_level=tuple(
+                Message(role=Role.SYSTEM, content=(TextBlock(text=text),)) for text in run_level
+            ),
+            goal_level=tuple(
+                Message(role=Role.USER, content=(TextBlock(text=text),)) for text in goal_level
+            ),
+        ),
+        injections=injections or {},
+        model_binding={},
+        model_replay_policy=ReplayPolicy.NEVER,
+        observation_template=TEMPLATE,
+        cancel_grace_seconds=1.0,
+    )
+
+
+def test_initial_prompt_chars_counts_every_segment() -> None:
+    request = a_request(
+        run_level=("a" * 10, "b" * 5),
+        goal_level=("c" * 7,),
+        injections={"skill": (Injection(entry_id="e0", content="d" * 3),)},
+    )
+    assert initial_prompt_chars(request) == 25
+
+
+def test_context_overflow_budget_leaves_room_for_exactly_the_first_step() -> None:
+    """上限 = 初始提示词 + 余量。第一步刚好装得下，第二步靠一步的增长撑过去。"""
+    request = a_request(run_level=("x" * 40,), goal_level=("y" * 60,))
+    budget = build_context_overflow_budget(request)
+    assert budget.max_prompt_chars == 100 + CONTEXT_OVERFLOW_SLACK_CHARS
+
+
+def test_initial_prompt_chars_rejects_an_unknown_block_type() -> None:
+    """认不得的块当成 0 会让上限算小，于是第一步就撞上限、这一类什么都验不到。"""
+
+    class _Weird:
+        pass
+
+    request = a_request()
+    broken = replace_context_block(request, _Weird())
+    with pytest.raises(Exception, match="认不得的内容块类型"):
+        initial_prompt_chars(broken)
+
+
+def replace_context_block(request: RunRequest, block: object) -> RunRequest:
+    """把上下文里那条消息的内容块换成给定的东西。造非法输入用。"""
+    import dataclasses
+
+    context = Context(
+        run_level=(Message(role=Role.SYSTEM, content=(block,)),),  # type: ignore[arg-type]
+        goal_level=(),
+    )
+    return dataclasses.replace(request, context=context)
+
+
+# ---------------------------------------------------------------------------
+# 十七、环境故障：判据
+# ---------------------------------------------------------------------------
+
+
+def test_stop_reason_env_error_passes_and_breaches() -> None:
+    good = as_read(step_completed(), run_finished(stop_reason="env_error"))
+    bad = as_read(step_completed(), run_finished(stop_reason="task_completed"))
+    assert check_stop_reason(good, "env_error").status is CriterionStatus.PASSED
+    assert check_stop_reason(bad, "env_error").status is CriterionStatus.BREACHED
+
+
+def test_last_step_action_status_passes() -> None:
+    read = as_read(
+        step_completed(step_idx=0, action_status="executed"),
+        step_completed(step_idx=1, action_status="env_error"),
+    )
+    assert check_last_step_action_status(read, expected="env_error").status is (
+        CriterionStatus.PASSED
+    )
+
+
+def test_last_step_action_status_breaches() -> None:
+    read = as_read(
+        step_completed(step_idx=0, action_status="env_error"),
+        step_completed(step_idx=1, action_status="executed"),
+    )
+    outcome = check_last_step_action_status(read, expected="env_error")
+    assert outcome.status is CriterionStatus.BREACHED
+    assert "executed" in outcome.evidence
+
+
+def test_last_step_action_status_is_undetermined_without_steps() -> None:
+    assert check_last_step_action_status(as_read(run_started()), expected="env_error").status is (
+        CriterionStatus.UNDETERMINED
+    )
+
+
+def test_env_failed_observation_passes_with_the_value_from_the_scenario() -> None:
+    """期望值从场景那份合成观察取，判据这边不抄一份字面量。"""
+    expected = build_synthetic_observations().env_failed
+    read = as_read(
+        step_completed(
+            action_status="env_error", observation=expected, observation_is_synthetic=True
+        )
+    )
+    assert check_last_observation_is_synthetic(read, expected=expected, name="x").status is (
+        CriterionStatus.PASSED
+    )
+
+
+def test_env_failed_observation_breaches_when_the_flag_is_false() -> None:
+    expected = build_synthetic_observations().env_failed
+    read = as_read(
+        step_completed(
+            action_status="env_error", observation=expected, observation_is_synthetic=False
+        )
+    )
+    outcome = check_last_observation_is_synthetic(read, expected=expected, name="x")
+    assert outcome.status is CriterionStatus.BREACHED
+    assert "observation_is_synthetic" in outcome.evidence
+
+
+def test_env_failed_observation_breaches_when_the_executor_text_survived() -> None:
+    """替换没发生的话，历史里躺着的是与环境通信那一层给的原文——那正是这一条要抓的。"""
+    expected = build_synthetic_observations().env_failed
+    read = as_read(
+        step_completed(
+            action_status="env_error",
+            observation="ConnectError: All connection attempts failed",
+            observation_is_synthetic=True,
+        )
+    )
+    outcome = check_last_observation_is_synthetic(read, expected=expected, name="x")
+    assert outcome.status is CriterionStatus.BREACHED
+    assert "ConnectError" not in outcome.evidence
+
+
+def test_env_failed_observation_is_undetermined_without_steps() -> None:
+    assert (
+        check_last_observation_is_synthetic(as_read(run_started()), expected="x", name="x").status
+        is CriterionStatus.UNDETERMINED
+    )
+
+
+def test_steps_before_last_all_executed_passes() -> None:
+    read = as_read(
+        step_completed(step_idx=0, action_status="executed"),
+        step_completed(step_idx=1, action_status="executed"),
+        step_completed(step_idx=2, action_status="env_error"),
+    )
+    assert check_steps_before_last_all_executed(read).status is CriterionStatus.PASSED
+
+
+def test_steps_before_last_all_executed_breaches() -> None:
+    """环境坏掉之前的步被改写或补上别的状态，说明一次局部故障扩散到了已经落地的轨迹上。"""
+    read = as_read(
+        step_completed(step_idx=0, action_status="executed"),
+        step_completed(step_idx=1, action_status="env_error"),
+        step_completed(step_idx=2, action_status="env_error"),
+    )
+    outcome = check_steps_before_last_all_executed(read)
+    assert outcome.status is CriterionStatus.BREACHED
+    assert "[1]" in outcome.evidence
+
+
+def test_steps_before_last_all_executed_is_undetermined_with_a_single_step() -> None:
+    """只有一步的话这一条真空成立，那种「通过」什么都没验。"""
+    outcome = check_steps_before_last_all_executed(as_read(step_completed()))
+    assert outcome.status is CriterionStatus.UNDETERMINED
+    assert "真空成立" in outcome.evidence
+
+
+def test_env_broken_after_a_full_step_passes() -> None:
+    outcome = check_env_broken_after_a_full_step(broken=True, executions_before_break=1)
+    assert outcome.status is CriterionStatus.PASSED
+
+
+def test_env_broken_after_a_full_step_is_undetermined_when_it_never_broke() -> None:
+    outcome = check_env_broken_after_a_full_step(broken=False, executions_before_break=0)
+    assert outcome.status is CriterionStatus.UNDETERMINED
+    assert "一次都没被弄坏" in outcome.evidence
+
+
+def test_env_broken_after_a_full_step_is_undetermined_when_it_broke_too_early() -> None:
+    """第一次执行之前就打死容器的话，压到的是初始化而不是动作执行接缝。"""
+    outcome = check_env_broken_after_a_full_step(broken=True, executions_before_break=0)
+    assert outcome.status is CriterionStatus.UNDETERMINED
+    assert "初始化" in outcome.evidence
+
+
+# ---------------------------------------------------------------------------
+# 十八、环境故障：杀容器那段编排里的纯函数与执行器包装
+# ---------------------------------------------------------------------------
+
+
+def test_container_name_for_port() -> None:
+    assert container_name_for_port(8201) == "polyloop-soak-appworld-8201"
+
+
+def test_should_break_env_waits_for_a_full_execution() -> None:
+    assert (
+        should_break_env(executions_done=0, break_after_executions=1, already_broken=False) is False
+    )
+    assert (
+        should_break_env(executions_done=1, break_after_executions=1, already_broken=False) is True
+    )
+
+
+def test_should_break_env_never_breaks_twice() -> None:
+    """容器已经没了，再发一次 docker kill 只会拿到一个「没有这个容器」的错误。"""
+    assert (
+        should_break_env(executions_done=5, break_after_executions=1, already_broken=True) is False
+    )
+
+
+class _FakeExecutor:
+    """按剧本一次次返回结果或抛异常的假执行器。"""
+
+    def __init__(self, script: list[object]) -> None:
+        self.script = script
+        self.calls = 0
+
+    def parameters(self) -> dict[str, str]:
+        return {"kind": "fake_appworld"}
+
+    async def execute(self, action: object) -> ActionOutcome:
+        item = self.script[self.calls]
+        self.calls += 1
+        if isinstance(item, BaseException):
+            raise item
+        return item  # type: ignore[return-value]
+
+
+def an_outcome(status: ActionStatus = ActionStatus.EXECUTED) -> ActionOutcome:
+    return ActionOutcome(
+        status=status,
+        observation="环境返回",
+        observation_is_synthetic=False,
+        env_reported_completion=False,
+        observation_truncated_chars=0,
+    )
+
+
+async def test_env_breaking_executor_breaks_after_one_full_execution() -> None:
+    """第一次执行之前不动手，第二次执行之前动手。"""
+    broke_at: list[int] = []
+    inner = _FakeExecutor([an_outcome(), httpx.ConnectError("All connection attempts failed")])
+
+    async def break_env() -> str:
+        broke_at.append(inner.calls)
+        return "容器已被打死"
+
+    executor = EnvBreakingExecutor(inner=inner, break_after_executions=1, break_env=break_env)
+    first = await executor.execute(object())
+    assert first.status is ActionStatus.EXECUTED
+    assert broke_at == []
+
+    second = await executor.execute(object())
+    assert broke_at == [1]
+    assert executor.broken is True
+    assert executor.executions_before_break == 1
+    assert executor.break_note == "容器已被打死"
+    assert second.status is ActionStatus.ENV_ERROR
+
+
+async def test_env_breaking_executor_translates_a_transport_error() -> None:
+    """场景那侧只接 AppWorldError，容器没了时抛的是 httpx.ConnectError，不翻译就整个抛出去。"""
+    inner = _FakeExecutor([httpx.ConnectError("All connection attempts failed")])
+
+    async def break_env() -> str:
+        return "打死了"
+
+    executor = EnvBreakingExecutor(inner=inner, break_after_executions=0, break_env=break_env)
+    outcome = await executor.execute(object())
+    assert outcome.status is ActionStatus.ENV_ERROR
+    assert outcome.observation_is_synthetic is False
+    assert "ConnectError" in outcome.observation
+
+
+async def test_env_breaking_executor_passes_an_inner_env_error_through() -> None:
+    """内层自己判出环境故障时原样透传：场景那边哪天补上转换，这里不用跟着改。"""
+    inner = _FakeExecutor([an_outcome(ActionStatus.ENV_ERROR)])
+
+    async def break_env() -> str:  # pragma: no cover - 这条用例不动手
+        raise AssertionError("不该动手")
+
+    executor = EnvBreakingExecutor(inner=inner, break_after_executions=99, break_env=break_env)
+    outcome = await executor.execute(object())
+    assert outcome.status is ActionStatus.ENV_ERROR
+    assert outcome.observation == "环境返回"
+
+
+async def test_env_breaking_executor_reports_its_probe_in_parameters() -> None:
+    inner = _FakeExecutor([])
+
+    async def break_env() -> str:  # pragma: no cover - 这条用例不执行动作
+        raise AssertionError("不该动手")
+
+    executor = EnvBreakingExecutor(inner=inner, break_after_executions=1, break_env=break_env)
+    assert executor.parameters() == {"kind": "fake_appworld", "env_break_probe": "docker_kill"}
+
+
+# ---------------------------------------------------------------------------
+# 十九、两类新故障接进命令行
+# ---------------------------------------------------------------------------
+
+
+def test_new_faults_are_in_the_default_selection() -> None:
+    """不给 --fault 时按 FAULT_NAMES 全跑，两类都得在里面。"""
+    assert "context_overflow" in FAULT_NAMES
+    assert "env_error" in FAULT_NAMES
+
+
+def test_parser_accepts_the_new_faults() -> None:
+    args = build_parser().parse_args(
+        [
+            "--runs-dir",
+            "x",
+            "--budget-calls",
+            "10",
+            "--fault",
+            "context_overflow",
+            "--fault",
+            "env_error",
+        ]
+    )
+    assert args.fault == ["context_overflow", "env_error"]