From f8ebe9a62172bf6534abc4a728c53ec8cb4b677d Mon Sep 17 00:00:00 2001
From: "jinli.yl" <jinli.yl@alibaba-inc.com>
Date: Thu, 5 Nov 2026 16:01:53 +0800
Subject: [PATCH] fix(dsh): finish environment lifecycle and readiness
 safeguards

---
 integrations/dsh/docs/environment.md          |  14 +-
 integrations/dsh/docs/environment_ZH.md       |  14 +-
 integrations/dsh/scripts/test-package.mjs     |   2 +-
 integrations/dsh/src/client/status-page.tsx   |   6 +-
 .../dsh/src/environment/client/dependency.tsx |   3 +-
 .../dsh/src/environment/client/locales.ts     |   7 +-
 .../dsh/src/environment/client/service.tsx    |  29 ++-
 .../dsh/src/environment/client/tab.tsx        |  11 +-
 .../dsh/src/environment/dependency.ts         |  38 +--
 .../dsh/src/environment/host/install.ts       |  14 +-
 .../dsh/src/environment/host/manager.ts       | 222 ++++++------------
 .../dsh/src/environment/host/runner.ts        |  17 ++
 .../dsh/src/environment/host/service.ts       |  58 +++--
 integrations/dsh/src/environment/types.ts     |   1 +
 integrations/dsh/tests/env-manager.test.mjs   | 166 +++++++++++++
 integrations/dsh/tests/env-rules.test.mjs     |  14 +-
 integrations/dsh/tests/env-service.test.mjs   | 186 ++++++++++++++-
 integrations/dsh/tests/env-tab.test.mjs       |  96 ++++++++
 18 files changed, 647 insertions(+), 251 deletions(-)

diff --git a/integrations/dsh/docs/environment.md b/integrations/dsh/docs/environment.md
index fbbdb05d..8fa41886 100644
--- a/integrations/dsh/docs/environment.md
+++ b/integrations/dsh/docs/environment.md
@@ -57,7 +57,8 @@ The check asks the selected interpreter three questions and reports them as metr
 
 - `reme-ai` metadata version (`importlib.metadata.version("reme-ai")`), and whether it satisfies the minimum
   this integration targets.
-- `[core]` extras: whether `import agentscope` works. Without it, `auto_memory` and `auto_dream` are unavailable.
+- `[core]` extras: whether `import agentscope` works. Supported ReMe releases import AgentScope while loading the
+  CLI, so it is required to start the service. Install or reinstall `reme-ai[core]` when it is missing.
 - `reme` CLI: the console script beside the interpreter, or the Python wrapper fallback used at start time.
 
 **Install reme-ai[core]** runs `python -m pip install reme-ai[core]`, optionally with a package index (PyPI,
@@ -186,14 +187,18 @@ processes it manages when the Host exits. The plugin owns a small service adapte
   user with a process to kill by hand.
 - **Stop** tree-kills the recorded process (process group on POSIX, `taskkill /T /F` on Windows), waits for it to
   exit, escalates (POSIX: `SIGTERM` then `SIGKILL`; Windows: force `taskkill` again), and clears the record only
-  after the pid is gone. A service started elsewhere stays untouched and is only observed.
+  after the pid and the POSIX process group are gone. A child that outlives its parent still receives the force-kill.
+  If the group cannot be confirmed empty, its record is retained; a later unverifiable group is never signalled again.
+  A service started elsewhere stays untouched and is only observed.
 - A recorded launch that is still alive but never became healthy is shown as **Last launch not ready** with both
   **Stop** and **Start**: Stop clears the record, while Start makes the Host stop a provably owned previous launch or
   discard a proven-foreign one. It is not shown as "Starting" unless a start from this tab is actually in flight.
 - **Start** is serialized: two requests cannot spawn two services, and a second request observes the launch
   already in flight. Before replacing a recorded launch that never became healthy, Start only kills it when
-  ownership is proven; an unproven record is kept and reported, never silently dropped.
+  ownership is proven; an unproven record is kept and reported, never silently dropped. The selected interpreter's
+  dependencies are checked before stopping the previous service.
 - **Auto-start** (`autoStart`, off by default) pulls the service up when DSH starts, if it is not already running.
+  A refused launch is reported in the DSH Host log.
 
 Python probes and pip installs are bounded Host operations; the service is the only process that must outlive DSH.
 
@@ -221,7 +226,8 @@ with other projects.
 **Saving `.env` is refused.** `LLM_API_KEY` and `EMBEDDING_API_KEY` must both be non-empty in the saved file;
 use `EMPTY` for the embedding key when vector search is off. Emptying a secret field never reaches the file, so
 the stored key is kept; a required key that is not stored at all still fails the save, and the file is left
-unchanged.
+unchanged. Only a missing file is treated as a first save; permission or I/O read errors abort the save without
+replacing the active file or its backup.
 
 **The service reports “Port occupied”.** Something else listens on the endpoint. Change the port in the service
 URL (Memory settings) or stop the other program.
diff --git a/integrations/dsh/docs/environment_ZH.md b/integrations/dsh/docs/environment_ZH.md
index 49394855..2e075b02 100644
--- a/integrations/dsh/docs/environment_ZH.md
+++ b/integrations/dsh/docs/environment_ZH.md
@@ -49,7 +49,8 @@ ReMe 需要 **Python 3.11 或更新版本**。标签页在 Host 上探测下列
 检查会向所选解释器询问三件事，并以指标形式展示：
 
 - `reme-ai` 元数据版本（`importlib.metadata.version("reme-ai")`），以及是否达到本集成要求的最低版本。
-- `[core]` 附加依赖：`import agentscope` 是否可用。缺失时 `auto_memory` 与 `auto_dream` 不可用。
+- `[core]` 附加依赖：`import agentscope` 是否可用。受支持的 ReMe 版本在加载 CLI 时就会导入 AgentScope，因此缺失时
+  无法启动服务；请安装或重装 `reme-ai[core]`。
 - `reme` CLI：解释器旁的命令行入口，或启动时回退使用的 Python 包装。
 
 **安装 reme-ai[core]** 执行 `python -m pip install reme-ai[core]`，可附加软件源（PyPI、清华、阿里云）。**升级**追加
@@ -146,13 +147,14 @@ ReMe 在服务启动时读取 workspace 目录下的 `.env`；标签页从不把
   一样被管理：给出**停止**按钮，**启动**在它尚未健康时替换它。它不会再被当成标签页无从处理的外部进程，否则用户
   只能自己去杀进程。
 - **停止**会树杀记录的进程（POSIX 上按进程组、Windows 上为 `taskkill /T /F`），等待其退出，必要时升级（POSIX：
-  `SIGTERM` 后 `SIGKILL`；Windows：再次强制 `taskkill`），并**在 pid 真正消失之后**才清除记录。别处启动的服务不受影响，
-  只会被观察。
+  `SIGTERM` 后 `SIGKILL`；Windows：再次强制 `taskkill`），并**在 pid 及 POSIX 进程组真正消失之后**才清除记录。
+  父进程先退出时，仍会强制结束存活的子进程。无法确认进程组已清空就保留记录；后续无法验证身份的进程组不会再次被发信号。
+  别处启动的服务不受影响，只会被观察。
 - 记录中的进程仍存活但从未就绪时，显示为**上次启动未就绪**，并同时给出**停止**与**启动**：停止负责清记录，启动则让 Host
   停掉可证明归属的旧启动、或丢弃已证明属于外部的记录。只有本标签页发起的启动仍在进行时才会显示“启动中”。
 - **启动**是串行化的：两个请求不会拉起两个服务，后到的请求会观察已在进行的启动。替换“一直没有就绪”的旧记录时，只有
-  归属被证明才会杀掉它；证明不了就保留记录并报错，不会静默丢弃。
-- **自动启动**（`autoStart`，默认关闭）会在 DSH 启动时把尚未运行的服务拉起。
+  归属被证明才会杀掉它；证明不了就保留记录并报错，不会静默丢弃。停止旧服务前会先检查所选解释器的启动依赖。
+- **自动启动**（`autoStart`，默认关闭）会在 DSH 启动时把尚未运行的服务拉起；被拒绝的启动会记入 DSH Host 日志。
 
 Python 探测与 pip 安装都是有界的 Host 操作；服务是唯一需要比 DSH 活得更久的进程。
 
@@ -172,6 +174,8 @@ Python 探测与 pip 安装都是有界的 Host 操作；服务是唯一需要
 
 **所选解释器不在列表里。** 标签页会用“不在探测结果中”标注它，但仍然使用它。重新探测，或改选探测到的解释器。
 
+**保存 `.env` 时读取失败。** 只有文件不存在才按首次保存处理；权限或 I/O 错误会中止保存，不会替换原文件或备份。
+
 **安装失败。** 先看日志尾部：缺少 wheel、代理配置过期或网络受限通常都能看出来，可以换一个软件源。conda 环境里 `pip` 也可
 用，但独立环境更能避免与其它项目的依赖冲突。
 
diff --git a/integrations/dsh/scripts/test-package.mjs b/integrations/dsh/scripts/test-package.mjs
index 6775cdb4..e42b5807 100644
--- a/integrations/dsh/scripts/test-package.mjs
+++ b/integrations/dsh/scripts/test-package.mjs
@@ -195,7 +195,7 @@ try {
       .map((file) => path.join("tests", file));
     const tested = await run(
       process.execPath,
-      ["--test", ...testFiles],
+      ["--test", "--test-reporter=tap", ...testFiles],
       installed,
       `tests DSH ${release.dsh}`,
     );
diff --git a/integrations/dsh/src/client/status-page.tsx b/integrations/dsh/src/client/status-page.tsx
index 8abf8e69..f7a4c1e2 100644
--- a/integrations/dsh/src/client/status-page.tsx
+++ b/integrations/dsh/src/client/status-page.tsx
@@ -1224,7 +1224,8 @@ function componentGroupLabel(group: string, t: StatusTranslator): string {
     file_store: "fileStore",
     keyword_index: "keywordIndex",
   };
-  return labels[group] === undefined ? readableName(group) : t(labels[group]);
+  const key = Object.hasOwn(labels, group) ? labels[group] : undefined;
+  return key === undefined ? readableName(group) : t(key);
 }
 
 function componentFieldLabel(field: string, t: StatusTranslator): string {
@@ -1242,7 +1243,8 @@ function componentFieldLabel(field: string, t: StatusTranslator): string {
     vocab_size: "vocabulary",
     memory: "memoryUsage",
   };
-  return labels[field] === undefined ? readableName(field) : t(labels[field]);
+  const key = Object.hasOwn(labels, field) ? labels[field] : undefined;
+  return key === undefined ? readableName(field) : t(key);
 }
 
 function readableName(value: string): string {
diff --git a/integrations/dsh/src/environment/client/dependency.tsx b/integrations/dsh/src/environment/client/dependency.tsx
index 92668728..00b03fbb 100644
--- a/integrations/dsh/src/environment/client/dependency.tsx
+++ b/integrations/dsh/src/environment/client/dependency.tsx
@@ -1,6 +1,7 @@
 import { useCallback, useEffect, useRef, useState } from "react";
 import type { StatusRpc } from "../../client/status-page.js";
 import { safeError } from "../../endpoint.js";
+import { canHostService } from "../dependency.js";
 import { interpreterKey } from "../interpreter-key.js";
 import type { InstallStatus, RemeCheck } from "../types.js";
 import { fill, type EnvTranslator } from "./locales.js";
@@ -368,7 +369,7 @@ export function DependencySection({
     ? undefined
     : !checkData.installed
     ? { tone: "progress" as const, text: t("depMissing") }
-    : checkData.versionOk && checkData.hasCore
+    : canHostService(checkData)
     ? { tone: "ok" as const, text: t("depReady") }
     : checkData.versionOk
     ? { tone: "progress" as const, text: t("coreMissingBadge") }
diff --git a/integrations/dsh/src/environment/client/locales.ts b/integrations/dsh/src/environment/client/locales.ts
index ed797fe7..4bd643f1 100644
--- a/integrations/dsh/src/environment/client/locales.ts
+++ b/integrations/dsh/src/environment/client/locales.ts
@@ -41,7 +41,7 @@ export const envEn = {
   notInstalled: "Not installed",
   upgradeRecommended: "upgrade recommended",
   coreOk: "Available",
-  coreMissing: "Missing (auto_memory / auto_dream unavailable)",
+  coreMissing: "Missing (required to start the service)",
   coreMissingBadge: "core missing",
   cliFallback: "python wrapper fallback",
   installButton: "Install reme-ai[core]",
@@ -130,6 +130,8 @@ export const envEn = {
     "reme-ai is not installed in the selected interpreter.",
   startErrorVersionTooOld:
     "The installed reme-ai is too old; upgrade it first.",
+  startErrorCoreMissing:
+    "AgentScope is missing; install reme-ai[core] before starting the service.",
   startErrorFailed: "The service could not be started; check the log.",
   stopNoRecord: "No service was started by this plugin.",
   stopForeign: "The recorded service does not belong to this endpoint.",
@@ -246,7 +248,7 @@ export const envZh: typeof envEn = {
   notInstalled: "未安装",
   upgradeRecommended: "建议升级",
   coreOk: "可用",
-  coreMissing: "缺失（auto_memory / auto_dream 不可用）",
+  coreMissing: "缺失（启动服务所必需）",
   coreMissingBadge: "缺少 core",
   cliFallback: "回退到 python 包装",
   installButton: "安装 reme-ai[core]",
@@ -325,6 +327,7 @@ export const envZh: typeof envEn = {
   startErrorNoPython: "请先选择一个 Python 解释器。",
   startErrorNotInstalled: "所选解释器尚未安装 reme-ai。",
   startErrorVersionTooOld: "已安装的 reme-ai 版本过低，请先升级。",
+  startErrorCoreMissing: "缺少 AgentScope，请先安装 reme-ai[core] 再启动服务。",
   startErrorFailed: "服务未能启动，请查看日志。",
   stopNoRecord: "本插件没有启动过该服务。",
   stopForeign: "记录中的服务不属于当前服务地址。",
diff --git a/integrations/dsh/src/environment/client/service.tsx b/integrations/dsh/src/environment/client/service.tsx
index 9b19c2c1..f314a878 100644
--- a/integrations/dsh/src/environment/client/service.tsx
+++ b/integrations/dsh/src/environment/client/service.tsx
@@ -39,6 +39,7 @@ const START_ERROR_KEYS: Record<string, EnvKey> = {
   "no-python": "startErrorNoPython",
   "not-installed": "startErrorNotInstalled",
   "version-too-old": "startErrorVersionTooOld",
+  "core-missing": "startErrorCoreMissing",
   "start-failed": "startErrorFailed",
 };
 
@@ -47,7 +48,10 @@ function startErrorText(t: EnvTranslator, result: ServiceStartResult): string {
   // can tell the user what to look for instead of a generic sentence.
   if (result.code === "unverified-record" && result.pid !== undefined)
     return fill(t("startErrorUnverifiedRecordPid"), { pid: result.pid });
-  const key = result.code ? START_ERROR_KEYS[result.code] : undefined;
+  const key =
+    result.code && Object.hasOwn(START_ERROR_KEYS, result.code)
+      ? START_ERROR_KEYS[result.code]
+      : undefined;
   return key ? t(key) : result.error || t("serviceError");
 }
 
@@ -63,7 +67,10 @@ function stopReasonText(
   t: EnvTranslator,
   result: { code?: string; reason?: string },
 ): string {
-  const key = result.code ? STOP_REASON_KEYS[result.code] : undefined;
+  const key =
+    result.code && Object.hasOwn(STOP_REASON_KEYS, result.code)
+      ? STOP_REASON_KEYS[result.code]
+      : undefined;
   return key ? t(key) : result.reason || t("serviceError");
 }
 
@@ -84,15 +91,15 @@ const RECORD_ONLY_CODES = new Set([
  * The Host names the record it refused on: that record may belong to another
  * endpoint than the one on screen, and forgetting the endpoint on screen
  * would be refused as foreign. A refusal that names no record (a conflict, a
- * missing interpreter) has no record-only way out. An older Host names no
- * record either, so the endpoint on screen stays the fallback.
+ * missing interpreter) has no record-only way out. An older Host that names
+ * no record cannot safely offer Forget for the endpoint on screen.
  */
-function recoveryFor(
-  result: { code?: string; record?: ServiceRecordRef },
-  endpoint: string,
-): ServiceRecordRef | undefined {
+function recoveryFor(result: {
+  code?: string;
+  record?: ServiceRecordRef;
+}): ServiceRecordRef | undefined {
   if (!result.code || !RECORD_ONLY_CODES.has(result.code)) return undefined;
-  return result.record ?? { endpoint };
+  return result.record;
 }
 
 export interface ServiceViewState {
@@ -313,7 +320,7 @@ export function useService(
         // the record-only escape hatch, aimed at the record the Host named.
         // A refusal that names no record leaves an existing offer alone: the
         // record it describes is still there.
-        const recovery = recoveryFor(started, endpoint);
+        const recovery = recoveryFor(started);
         if (recovery) setForgetTarget(recovery);
         applyState({ phase: "error", error: startErrorText(t, started) });
         return;
@@ -415,7 +422,7 @@ export function useService(
       // A record the Host refuses to stop (unverifiable, or a process that
       // survived the force-kill) cannot be cleared by either button: offer the
       // record-only way out instead of leaving two actions that both fail.
-      const recovery = recoveryFor(result, target);
+      const recovery = recoveryFor(result);
       if (recovery) setForgetTarget(recovery);
       // A stopped service has no record left; a refusal that names none (a
       // foreign record, a missing one) leaves an existing offer alone.
diff --git a/integrations/dsh/src/environment/client/tab.tsx b/integrations/dsh/src/environment/client/tab.tsx
index 453e8ca0..6fef1658 100644
--- a/integrations/dsh/src/environment/client/tab.tsx
+++ b/integrations/dsh/src/environment/client/tab.tsx
@@ -5,7 +5,7 @@ import type { StatusRpc } from "../../client/status-page.js";
 import { safeError } from "../../endpoint.js";
 import { serviceEndpointKey } from "../endpoint-key.js";
 import { isLocalEndpoint } from "../endpoint-rules.js";
-import { hasCoreFeatures } from "../dependency.js";
+import { canHostService } from "../dependency.js";
 import type { HealthErrorCode, RemeCheck } from "../types.js";
 import type { ReMeSettings } from "../../types.js";
 import { DependencySection, useDependency } from "./dependency.js";
@@ -60,7 +60,10 @@ function healthErrorText(
   connection: ConnectionState,
 ): string {
   if (connection.phase !== "fail") return "";
-  const key = connection.code ? HEALTH_ERROR_KEYS[connection.code] : undefined;
+  const key =
+    connection.code && Object.hasOwn(HEALTH_ERROR_KEYS, connection.code)
+      ? HEALTH_ERROR_KEYS[connection.code]
+      : undefined;
   return key ? t(key) : connection.error ?? "";
 }
 
@@ -95,7 +98,7 @@ function remeSummaryBadge(
       text: `${t("heroReme")} · ${t("notInstalled")}`,
     };
   return {
-    tone: check.versionOk && check.hasCore ? "ok" : "progress",
+    tone: canHostService(check) ? "ok" : "progress",
     text: `${t("heroReme")} ${check.version}`,
   };
 }
@@ -215,7 +218,7 @@ export function ReMeEnvironmentTab({
   const ready =
     current &&
     connection.phase === "ok" &&
-    (!local || hasCoreFeatures(dependency.checkData));
+    (!local || canHostService(dependency.checkData));
   const scannedAt = python.detection.data?.scannedAt
     ? Date.parse(python.detection.data.scannedAt)
     : Number.NaN;
diff --git a/integrations/dsh/src/environment/dependency.ts b/integrations/dsh/src/environment/dependency.ts
index 6487f4c4..83894e41 100644
--- a/integrations/dsh/src/environment/dependency.ts
+++ b/integrations/dsh/src/environment/dependency.ts
@@ -1,36 +1,14 @@
-/**
- * What one interpreter can and cannot run.
- *
- * The dependency card, the hero and the service card all have to answer the
- * same question about the selected interpreter, and the Host answers it again
- * when a start is requested. The answers live here so the four cannot drift
- * apart: a button that is offered for an interpreter the Host will refuse
- * only produces an error, and a button that is hidden for one the Host would
- * accept takes a capability away.
- *
- * This module stays browser-safe: the client imports it too.
- */
+/** Shared, browser-safe readiness rule for the Host and setup cards. */
 import type { RemeCheck } from "./types.js";
 
 /**
- * Whether the interpreter can host the ReMe service.
- *
- * This is the Host's own start gate: `reme-ai` must be installed and satisfy
- * the minimum version, because the Host refuses a start otherwise with
- * `not-installed` or `version-too-old`.
+ * Supported ReMe releases import AgentScope while loading the CLI, so a bare
+ * installation cannot start the service. Install `reme-ai[core]` first.
  */
 export function canHostService(check: RemeCheck | undefined): boolean {
-  return check?.installed === true && check.versionOk === true;
-}
-
-/**
- * Whether the interpreter offers the whole feature set.
- *
- * The `[core]` extras provide automatic memory and automatic consolidation, so
- * an interpreter without them runs the service but not those two jobs. The
- * hero reports this state; a start is still offered, because the Host accepts
- * one and search still works.
- */
-export function hasCoreFeatures(check: RemeCheck | undefined): boolean {
-  return canHostService(check) && check?.hasCore === true;
+  return (
+    check?.installed === true &&
+    check.versionOk === true &&
+    check.hasCore === true
+  );
 }
diff --git a/integrations/dsh/src/environment/host/install.ts b/integrations/dsh/src/environment/host/install.ts
index b6c437b9..5a66e9f8 100644
--- a/integrations/dsh/src/environment/host/install.ts
+++ b/integrations/dsh/src/environment/host/install.ts
@@ -6,6 +6,7 @@ import type { InstallPhase, InstallRequest, InstallStatus } from "../types.js";
 import { interpreterKey } from "../interpreter-key.js";
 import { INSTALL_LOG_KEEP, openAppendLog, pruneInstallLogs } from "./log.js";
 import { isAbsolutePath } from "./paths.js";
+import { processGroupAlive } from "./runner.js";
 
 export interface InstallChild {
   pid: number | undefined;
@@ -172,18 +173,7 @@ export function createInstallSpawner(
           }
         },
         groupAlive() {
-          // Only POSIX puts the install in its own process group, and only
-          // there can the leader exit while the group outlives it.
-          if (process.platform === "win32" || child.pid === undefined)
-            return false;
-          try {
-            process.kill(-child.pid, 0);
-            return true;
-          } catch (error) {
-            // ESRCH means the group is empty; anything else cannot be proven
-            // empty, so the job waits instead of settling early.
-            return (error as NodeJS.ErrnoException).code !== "ESRCH";
-          }
+          return processGroupAlive(child.pid);
         },
       };
     },
diff --git a/integrations/dsh/src/environment/host/manager.ts b/integrations/dsh/src/environment/host/manager.ts
index de3a2462..34a37d4c 100644
--- a/integrations/dsh/src/environment/host/manager.ts
+++ b/integrations/dsh/src/environment/host/manager.ts
@@ -165,8 +165,8 @@ export class ReMeEnvManager {
     let existing = "";
     try {
       existing = readFileSync(path, "utf8");
-    } catch {
-      // First write creates the file.
+    } catch (error) {
+      if ((error as NodeJS.ErrnoException).code !== "ENOENT") throw error;
     }
     const stored = parseEnvFile(existing);
     // The update rules are applied here as well as in the tab: a client that
@@ -345,12 +345,14 @@ export class ReMeEnvManager {
       pythonPath = detection.suggested;
     }
     if (!pythonPath) return;
-    await this.serviceStart(
+    const result = await this.serviceStart(
       options.endpoint,
       pythonPath,
       options.workspaceDir,
       options.authToken ?? "",
     );
+    if (!result.started && !result.alreadyRunning)
+      throw new Error(result.error || "Could not auto-start the ReMe service");
   }
 
   /**
@@ -567,41 +569,31 @@ export class ReMeEnvManager {
         startedAt: now,
         ...(current.version ? { version: current.version } : {}),
       };
-    if (current.phase === "conflict") {
-      // The port is answered by something that is not a healthy service. The
-      // record may name that process: one of ours (still booting or rejecting
-      // our token) is stopped and replaced; one whose identity cannot be read
-      // is named, so the tab can forget it; anything else is left alone.
-      const { record, ownership } = await this.recordedService();
-      if (
-        record &&
-        ownership === "owned" &&
-        isLocalEndpoint(endpointValue) &&
-        this.sameOrigin(record.endpoint, endpointValue)
-      ) {
-        const previous = await stopService(this.serviceIO, {
-          statePath: this.serviceStatePath,
-          endpoint: record.endpoint,
-          ownership: "owned",
-        });
-        if (!previous.stopped)
-          return this.refused(
-            logPath,
-            now,
-            "previous-not-stopped",
-            `A previous launch could not be stopped: ${
-              previous.reason ?? "unknown reason"
-            }`,
-            { record: previous.record },
-          );
-      } else if (
+    const { record, ownership, alive } = await this.recordedService();
+    const replace =
+      record !== undefined &&
+      ownership === "owned" &&
+      isLocalEndpoint(endpointValue) &&
+      this.sameOrigin(record.endpoint, endpointValue);
+    // A port conflict is replaceable only when this record proves that our
+    // own service holds it. An unverified related record retains Forget.
+    if (
+      current.phase === "conflict" &&
+      !replace &&
+      !(
         record &&
         ownership === "unknown" &&
         this.relatedRecord(record.endpoint, endpointValue)
-      ) {
-        // The process may be ours, but its identity cannot be read: it must
-        // never be signalled. The record has to be named anyway, because it is
-        // the only way out of a port the tab cannot clear.
+      )
+    )
+      return this.refused(
+        logPath,
+        now,
+        "conflict",
+        "Another process is already listening on this endpoint",
+      );
+    if (record && alive) {
+      if (ownership === "unknown")
         return this.refused(
           logPath,
           now,
@@ -609,117 +601,13 @@ export class ReMeEnvManager {
           `The recorded service for ${record.endpoint} (pid ${record.pid}) could not be verified; leaving it untouched`,
           { pid: record.pid, record: serviceRecordRef(record) },
         );
-      } else {
+      if (ownership === "owned" && !replace)
         return this.refused(
           logPath,
           now,
-          "conflict",
-          "Another process is already listening on this endpoint",
+          "other-endpoint-running",
+          `A service for ${record.endpoint} is still running; stop it from that endpoint first`,
         );
-      }
-    }
-    // A record for a *different* endpoint that is still alive would be
-    // overwritten by the new launch, leaving that endpoint unable to stop it.
-    // A provably owned or an unverifiable process blocks the new start; only a
-    // provably foreign record is discarded, just like the same-endpoint case
-    // below.
-    const other = await this.recordedService();
-    const recorded = other.record;
-    if (
-      recorded &&
-      other.alive &&
-      serviceEndpointKey(recorded.endpoint) !==
-        serviceEndpointKey(endpointValue)
-    ) {
-      if (other.ownership === "owned") {
-        // The launch configures only host and port, so two endpoints on the
-        // same origin name the same local service even when their paths
-        // differ. A record left by a version that still launched a prefixed
-        // endpoint (for example `/reme`) is that service, and the endpoint on
-        // screen cannot reach it to stop it: replace it here instead of
-        // refusing with an instruction the tab cannot carry out.
-        //
-        // Only a launchable request may replace it: a prefixed request is
-        // refused by `buildStartCommand` below, so stopping a healthy
-        // same-origin service first would leave nothing running (autoStart
-        // would do that on every DSH start).
-        if (
-          isLocalEndpoint(endpointValue) &&
-          this.sameOrigin(recorded.endpoint, endpointValue)
-        ) {
-          const previous = await stopService(this.serviceIO, {
-            statePath: this.serviceStatePath,
-            endpoint: recorded.endpoint,
-            ownership: "owned",
-          });
-          if (!previous.stopped)
-            return this.refused(
-              logPath,
-              now,
-              "previous-not-stopped",
-              `A previous launch could not be stopped: ${
-                previous.reason ?? "unknown reason"
-              }`,
-              { record: previous.record },
-            );
-        } else
-          return this.refused(
-            logPath,
-            now,
-            "other-endpoint-running",
-            `A service for ${recorded.endpoint} is still running; stop it from that endpoint first`,
-          );
-      }
-      // An unreadable image/command line is not proof the process is gone:
-      // dropping the record would orphan a live service this plugin can no
-      // longer stop. Keep it and report why the start is blocked. The record is
-      // named, so the client can offer to forget exactly this one.
-      if (other.ownership === "unknown")
-        return this.refused(
-          logPath,
-          now,
-          "unverified-record",
-          `The recorded service for ${recorded.endpoint} (pid ${recorded.pid}) could not be verified; leaving it untouched`,
-          { pid: recorded.pid, record: serviceRecordRef(recorded) },
-        );
-      removeServiceState(this.serviceStatePath);
-    }
-    // A previous launch that never became healthy may still be alive. Stop it
-    // when ownership is proven; an unprovable record is kept and reported,
-    // because dropping it would orphan a live process the tab cannot stop.
-    if (current.pid !== undefined) {
-      if (other.ownership === "owned") {
-        const previous = await stopService(this.serviceIO, {
-          statePath: this.serviceStatePath,
-          endpoint: endpointValue,
-          ownership: "owned",
-        });
-        if (!previous.stopped)
-          return this.refused(
-            logPath,
-            now,
-            "previous-not-stopped",
-            `A previous launch could not be stopped: ${
-              previous.reason ?? "unknown reason"
-            }`,
-            { record: previous.record },
-          );
-      } else if (other.ownership === "unknown") {
-        // PowerShell/ps failed to describe a live process. Discarding the
-        // record here would orphan it: the tab could never stop or replace it.
-        // The message and the record name the same pid: it is the one the
-        // confirmed Forget is pinned to.
-        const pid = other.record?.pid ?? current.pid;
-        return this.refused(
-          logPath,
-          now,
-          "unverified-record",
-          `The recorded service for ${endpointValue} (pid ${pid}) could not be verified; leaving it untouched`,
-          { pid, record: serviceRecordRef(other.record) },
-        );
-      } else {
-        removeServiceState(this.serviceStatePath);
-      }
     }
     const path = pythonPath.trim();
     if (!path)
@@ -732,17 +620,45 @@ export class ReMeEnvManager {
     const check = await this.checkReme(path);
     // The same rule the tab uses to offer a start decides it here, so a
     // button is never offered for an interpreter this refuses.
-    if (!canHostService(check))
-      return this.refused(
-        logPath,
-        now,
-        check.installed ? "version-too-old" : "not-installed",
-        check.installed
-          ? `reme-ai ${
-              check.version || "(unknown version)"
-            } is older than ${MINIMUM_REME}; upgrade it first`
-          : "reme-ai is not installed in the selected interpreter",
-      );
+    if (!canHostService(check)) {
+      const code = !check.installed
+        ? "not-installed"
+        : !check.versionOk
+        ? "version-too-old"
+        : "core-missing";
+      const errors = {
+        "not-installed": "reme-ai is not installed in the selected interpreter",
+        "version-too-old": `reme-ai ${
+          check.version || "(unknown version)"
+        } is older than ${MINIMUM_REME}; upgrade it first`,
+        "core-missing":
+          "AgentScope is required to start ReMe; install reme-ai[core] in the selected interpreter",
+      };
+      return this.refused(logPath, now, code, errors[code]);
+    }
+    // All replacement cases share this path. Validate the new interpreter
+    // before stopping anything, then re-verify ownership at the stop boundary.
+    if (replace && record) {
+      const previous = await stopService(this.serviceIO, {
+        statePath: this.serviceStatePath,
+        endpoint: record.endpoint,
+        expectPid: record.pid,
+      });
+      const remaining = readServiceState(this.serviceStatePath);
+      if (!previous.stopped || remaining)
+        return this.refused(
+          logPath,
+          now,
+          "previous-not-stopped",
+          `A previous launch could not be stopped: ${
+            previous.reason ?? "the service record changed while stopping"
+          }`,
+          { record: previous.record ?? serviceRecordRef(remaining) },
+        );
+    } else if (record) {
+      // Only dead or provably foreign records reach here.
+      removeServiceState(this.serviceStatePath);
+    }
     // Set before the spawn so a second request arriving while the service is
     // booting observes the first launch instead of spawning another one. It is
     // cleared again when the spawn fails, so a retry is possible immediately.
diff --git a/integrations/dsh/src/environment/host/runner.ts b/integrations/dsh/src/environment/host/runner.ts
index 5e568adf..5a76283b 100644
--- a/integrations/dsh/src/environment/host/runner.ts
+++ b/integrations/dsh/src/environment/host/runner.ts
@@ -1,5 +1,22 @@
 import { spawn } from "node:child_process";
 
+/** Only ESRCH proves a detached POSIX process group is empty. */
+export function processGroupAlive(pid: number | undefined): boolean {
+  if (
+    process.platform === "win32" ||
+    pid === undefined ||
+    !Number.isInteger(pid) ||
+    pid <= 1
+  )
+    return false;
+  try {
+    process.kill(-pid, 0);
+    return true;
+  } catch (error) {
+    return (error as NodeJS.ErrnoException).code !== "ESRCH";
+  }
+}
+
 export interface RunResult {
   code: number | null;
   stdout: string;
diff --git a/integrations/dsh/src/environment/host/service.ts b/integrations/dsh/src/environment/host/service.ts
index 511a6bd5..8feaa6cf 100644
--- a/integrations/dsh/src/environment/host/service.ts
+++ b/integrations/dsh/src/environment/host/service.ts
@@ -26,6 +26,7 @@ import type {
 } from "../types.js";
 import { openAppendLog } from "./log.js";
 import { isWindowsPath } from "./paths.js";
+import { processGroupAlive } from "./runner.js";
 
 export { serviceEndpointKey, serviceOriginKey } from "../endpoint-key.js";
 export { parseLocalEndpoint } from "../endpoint-rules.js";
@@ -73,6 +74,8 @@ export interface ServiceIO {
    */
   killTree(pid: number, force?: boolean): void;
   probePid(pid: number): void;
+  /** Whether the detached POSIX process group still exists after its leader exits. */
+  groupAlive?(pid: number): boolean;
   /** OS image name of a pid, or "" when it cannot be read. */
   processImage(pid: number): Promise<string>;
   /** Full command line of a pid, or "" when it cannot be read. */
@@ -208,9 +211,9 @@ function alive(io: ServiceIO, pid?: number): boolean {
   }
 }
 
-/** Whether a pid is alive, rejecting pids this plugin never records. */
+/** Whether the recorded pid or its detached process group still exists. */
 export function processAlive(io: ServiceIO, pid?: number): boolean {
-  return alive(io, pid);
+  return isValidPid(pid) && (alive(io, pid) || io.groupAlive?.(pid) === true);
 }
 
 /**
@@ -305,7 +308,10 @@ export async function serviceOwnership(
   if (!persisted || !isValidPid(persisted.pid)) return "foreign";
   if (serviceEndpointKey(persisted.endpoint) !== serviceEndpointKey(endpoint))
     return "foreign";
-  if (!alive(io, persisted.pid)) return "foreign";
+  // A failed stop may leave children after the verified leader exited. Keep
+  // the record, but do not claim ownership we can no longer verify.
+  if (!alive(io, persisted.pid))
+    return processAlive(io, persisted.pid) ? "unknown" : "foreign";
   let image = "";
   try {
     image = await io.processImage(persisted.pid);
@@ -358,7 +364,7 @@ export async function serviceStatus(
     persisted !== undefined &&
     serviceEndpointKey(persisted.endpoint) ===
       serviceEndpointKey(options.endpoint);
-  const recordAlive = alive(io, persisted?.pid);
+  const recordAlive = processAlive(io, persisted?.pid);
   // A record whose process is gone must not be reported, or a later start
   // would keep seeing a stale pid. Remove it while nobody can be relying on it.
   if (persisted && !recordAlive) clearServiceState(options.statePath);
@@ -562,7 +568,7 @@ function delay(ms: number): Promise<void> {
   });
 }
 
-/** Poll until the pid disappears; true when it exited within `timeoutMs`. */
+/** Wait for both the leader and its detached process group to disappear. */
 async function waitForExit(
   io: ServiceIO,
   pid: number,
@@ -571,7 +577,7 @@ async function waitForExit(
 ): Promise<boolean> {
   const deadline = Date.now() + timeoutMs;
   for (;;) {
-    if (!alive(io, pid)) return true;
+    if (!processAlive(io, pid)) return true;
     const remaining = deadline - Date.now();
     if (remaining <= 0) return false;
     await delay(Math.max(1, Math.min(pollMs, remaining)));
@@ -582,7 +588,7 @@ async function waitForExit(
  * Stop the service this plugin started for the endpoint, and only that one: a
  * service on another port, or a foreign process, is left running.
  *
- * The record is removed only after the process is confirmed gone. Otherwise a
+ * The record is removed only after the process group is confirmed gone. Otherwise a
  * SIGTERM the service ignored would delete the pid, leaving a running process
  * that the tab can never stop again.
  */
@@ -591,12 +597,12 @@ export async function stopService(
   options: {
     statePath: string;
     endpoint: string;
+    /** Pin a replacement to the process inspected before dependency checks. */
+    expectPid?: number;
     /** Grace period before escalating to SIGKILL (tests shorten it). */
     timeoutMs?: number;
     forceTimeoutMs?: number;
     pollMs?: number;
-    /** Precomputed ownership from the caller; avoids a second process probe. */
-    ownership?: ServiceOwnership;
   },
 ): Promise<ServiceStopResult> {
   const persisted = readServiceState(options.statePath);
@@ -608,9 +614,14 @@ export async function stopService(
       code: "no-record",
     };
   }
-  const ownership =
-    options.ownership ??
-    (await serviceOwnership(io, persisted, options.endpoint));
+  if (options.expectPid !== undefined && persisted.pid !== options.expectPid)
+    return {
+      stopped: false,
+      reason: "The recorded service changed since it was inspected",
+      code: "record-changed",
+      record: serviceRecordRef(persisted),
+    };
+  const ownership = await serviceOwnership(io, persisted, options.endpoint);
   if (ownership === "unknown")
     return {
       stopped: false,
@@ -626,6 +637,24 @@ export async function stopService(
       code: "foreign",
     };
   const pid = persisted.pid;
+  const isCurrentRecord = (): boolean => {
+    const current = readServiceState(options.statePath);
+    return (
+      current?.pid === pid &&
+      current.endpoint === persisted.endpoint &&
+      current.startedAt === persisted.startedAt
+    );
+  };
+  // Identity reads yield to the event loop. Never signal a record that was
+  // replaced while those reads were in flight, or erase a newer launch later.
+  if (!isCurrentRecord())
+    return {
+      stopped: false,
+      pid,
+      reason: "The recorded service changed since it was inspected",
+      code: "record-changed",
+      record: serviceRecordRef(readServiceState(options.statePath)),
+    };
   const pollMs = options.pollMs ?? STOP_POLL_MS;
   try {
     io.killTree(pid);
@@ -635,7 +664,7 @@ export async function stopService(
   if (
     await waitForExit(io, pid, options.timeoutMs ?? STOP_TIMEOUT_MS, pollMs)
   ) {
-    clearServiceState(options.statePath);
+    if (isCurrentRecord()) clearServiceState(options.statePath);
     return { stopped: true, pid };
   }
   // The service ignored (or slowly handled) SIGTERM: escalate, then only drop
@@ -653,7 +682,7 @@ export async function stopService(
       pollMs,
     )
   ) {
-    clearServiceState(options.statePath);
+    if (isCurrentRecord()) clearServiceState(options.statePath);
     return { stopped: true, pid };
   }
   return {
@@ -863,6 +892,7 @@ export function createServiceIO(): ServiceIO {
         throw new RangeError("Refusing to probe an invalid pid");
       process.kill(pid, 0);
     },
+    groupAlive: processGroupAlive,
     processImage(pid) {
       return new Promise((resolve) => {
         if (!isValidPid(pid)) {
diff --git a/integrations/dsh/src/environment/types.ts b/integrations/dsh/src/environment/types.ts
index a4e1e299..8ad1ddc5 100644
--- a/integrations/dsh/src/environment/types.ts
+++ b/integrations/dsh/src/environment/types.ts
@@ -164,6 +164,7 @@ export type ServiceStartErrorCode =
   | "no-python"
   | "not-installed"
   | "version-too-old"
+  | "core-missing"
   | "start-failed";
 
 /** Stable reason for a refused/unsuccessful stop, so the client can localize it. */
diff --git a/integrations/dsh/tests/env-manager.test.mjs b/integrations/dsh/tests/env-manager.test.mjs
index 823979fe..711eeffe 100644
--- a/integrations/dsh/tests/env-manager.test.mjs
+++ b/integrations/dsh/tests/env-manager.test.mjs
@@ -1,5 +1,7 @@
 import assert from "node:assert/strict";
 import test from "node:test";
+import fs from "node:fs";
+import { syncBuiltinESMExports } from "node:module";
 import {
   mkdirSync,
   mkdtempSync,
@@ -139,6 +141,130 @@ test("a failed spawn can be retried immediately", async (t) => {
   assert.equal(calls.spawn.length, 2);
 });
 
+test("auto-start reports a refused launch to the Host logger boundary", async (t) => {
+  const { manager, directory, calls } = managerIn(t);
+  manager.checkReme = async () => ({
+    installed: true,
+    version: "0.4.2.1",
+    versionOk: true,
+    hasCore: false,
+    cliPath: "",
+    error: "",
+  });
+  await assert.rejects(
+    manager.autoStart({
+      endpoint: "http://127.0.0.1:2334",
+      pythonPath: "/env/bin/python",
+      workspaceDir: directory,
+    }),
+    /AgentScope/,
+  );
+  assert.equal(calls.spawn.length, 0);
+});
+
+test("missing core dependencies leave the previous service untouched", async (t) => {
+  const { manager, directory, calls, io } = managerIn(t);
+  const statePath = join(directory, "reme-memory", "service.json");
+  writeServiceState(statePath, {
+    pid: 6000,
+    endpoint: "http://127.0.0.1:2334",
+    workspaceDir: directory,
+    pythonPath: "/old/bin/python",
+    command: "reme start",
+    startedAt: "old",
+  });
+  io.processCommandLine = async () =>
+    `reme start workspace_dir=${directory} service.port=2334`;
+  io.killTree = (pid) => calls.killTree.push(pid);
+  manager.checkReme = async () => ({
+    installed: true,
+    version: "0.4.2.1",
+    versionOk: true,
+    hasCore: false,
+    cliPath: "",
+    error: "",
+  });
+  const result = await manager.serviceStart(
+    "http://127.0.0.1:2334",
+    "/bare/bin/python",
+    directory,
+  );
+  assert.equal(result.started, false);
+  assert.equal(result.code, "core-missing");
+  assert.match(result.error, /AgentScope/);
+  assert.deepEqual(calls.killTree, []);
+  assert.deepEqual(calls.spawn, []);
+  assert.equal(readServiceState(statePath)?.pid, 6000);
+});
+
+test("a replacement never stops a launch recorded during the dependency check", async (t) => {
+  const { manager, directory, calls, io } = managerIn(t);
+  const statePath = join(directory, "reme-memory", "service.json");
+  const original = {
+    pid: 6000,
+    endpoint: "http://127.0.0.1:2334",
+    workspaceDir: directory,
+    pythonPath: "/old/bin/python",
+    command: "reme start",
+    startedAt: "old",
+  };
+  writeServiceState(statePath, original);
+  io.processCommandLine = async () =>
+    `reme start workspace_dir=${directory} service.port=2334`;
+  io.killTree = (pid) => calls.killTree.push(pid);
+  const check = manager.checkReme;
+  manager.checkReme = async (path) => {
+    writeServiceState(statePath, { ...original, pid: 7000, startedAt: "new" });
+    return check(path);
+  };
+  const result = await manager.serviceStart(
+    original.endpoint,
+    "/new/bin/python",
+    directory,
+  );
+  assert.equal(result.code, "previous-not-stopped");
+  assert.deepEqual(result.record, { endpoint: original.endpoint, pid: 7000 });
+  assert.deepEqual(calls.killTree, []);
+  assert.deepEqual(calls.spawn, []);
+  assert.equal(readServiceState(statePath)?.pid, 7000);
+});
+
+test("a replacement never overwrites a launch recorded while the old service stops", async (t) => {
+  const { manager, directory, calls, io } = managerIn(t);
+  const statePath = join(directory, "reme-memory", "service.json");
+  const original = {
+    pid: 6000,
+    endpoint: "http://127.0.0.1:2334",
+    workspaceDir: directory,
+    pythonPath: "/old/bin/python",
+    command: "reme start",
+    startedAt: "old",
+  };
+  writeServiceState(statePath, original);
+  io.processCommandLine = async () =>
+    `reme start workspace_dir=${directory} service.port=2334`;
+  let running = true;
+  io.probePid = (pid) => {
+    if (pid === 6000 && !running)
+      throw Object.assign(new Error("gone"), { code: "ESRCH" });
+  };
+  io.killTree = (pid) => {
+    calls.killTree.push(pid);
+    running = false;
+    writeServiceState(statePath, { ...original, pid: 7000, startedAt: "new" });
+  };
+  const result = await manager.serviceStart(
+    original.endpoint,
+    "/new/bin/python",
+    directory,
+  );
+  assert.equal(result.code, "previous-not-stopped");
+  assert.deepEqual(result.record, { endpoint: original.endpoint, pid: 7000 });
+  assert.deepEqual(calls.killTree, [6000]);
+  assert.deepEqual(calls.spawn, []);
+  assert.equal(readServiceState(statePath)?.pid, 7000);
+});
+
 test("refuses to spawn while another process owns the port", async (t) => {
   const { manager, calls, directory } = managerIn(t);
   manager.serviceStatus = async (endpoint) => ({
@@ -863,3 +989,43 @@ test("writes .env atomically with a backup and owner-only mode", (t) => {
   if (process.platform !== "win32")
     assert.equal(statSync(envPath).mode & 0o777, 0o600);
 });
+
+for (const code of ["EIO", "EACCES"]) {
+  test(`a ${code} .env read failure preserves the file and backup`, (t) => {
+    const { manager, directory } = managerIn(t);
+    const envPath = join(directory, ".env");
+    const original = "# keep\r\nLLM_API_KEY=old\r\nUNRELATED=keep\r\n";
+    writeFileSync(envPath, original);
+    writeFileSync(`${envPath}.bak`, "previous backup");
+    const read = fs.readFileSync;
+    let injected = false;
+    const stub = t.mock.method(fs, "readFileSync", (path, ...args) => {
+      if (path === envPath && !injected) {
+        injected = true;
+        throw Object.assign(new Error(code), { code });
+      }
+      return read(path, ...args);
+    });
+    syncBuiltinESMExports();
+    try {
+      assert.throws(() => manager.writeEnv(directory, { LLM_API_KEY: "new" }), {
+        code,
+      });
+    } finally {
+      stub.mock.restore();
+      syncBuiltinESMExports();
+    }
+    assert.equal(injected, true);
+    assert.equal(readFileSync(envPath, "utf8"), original);
+    assert.equal(readFileSync(`${envPath}.bak`, "utf8"), "previous backup");
+  });
+}
+
+test("a missing .env can still be created on the first save", (t) => {
+  const { manager, directory } = managerIn(t);
+  manager.writeEnv(directory, { LLM_API_KEY: "new" });
+  assert.match(
+    readFileSync(join(directory, ".env"), "utf8"),
+    /^LLM_API_KEY=new$/m,
+  );
+});
diff --git a/integrations/dsh/tests/env-rules.test.mjs b/integrations/dsh/tests/env-rules.test.mjs
index 820c070f..5425cc08 100644
--- a/integrations/dsh/tests/env-rules.test.mjs
+++ b/integrations/dsh/tests/env-rules.test.mjs
@@ -4,10 +4,7 @@ import { mkdtempSync, readFileSync, rmSync, writeFileSync } from "node:fs";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
 
-import {
-  canHostService,
-  hasCoreFeatures,
-} from "../dist/environment/dependency.js";
+import { canHostService } from "../dist/environment/dependency.js";
 import {
   isLocalEndpoint,
   parseLocalEndpoint,
@@ -45,8 +42,7 @@ const INSTALLED = {
 };
 
 test("the interpreter readiness has one definition", () => {
-  // The Host refuses a start unless reme-ai is installed and new enough, so
-  // the tab must offer exactly the same starts.
+  // Supported CLI releases need AgentScope even before running any jobs.
   assert.equal(canHostService(INSTALLED), true);
   assert.equal(canHostService(undefined), false);
   assert.equal(
@@ -55,11 +51,7 @@ test("the interpreter readiness has one definition", () => {
   );
   assert.equal(canHostService({ ...INSTALLED, versionOk: false }), false);
 
-  // The [core] extras are a stronger state: without them the service still
-  // starts, but automatic memory and consolidation do not.
-  assert.equal(hasCoreFeatures(INSTALLED), true);
-  assert.equal(hasCoreFeatures({ ...INSTALLED, hasCore: false }), false);
-  assert.equal(hasCoreFeatures({ ...INSTALLED, versionOk: false }), false);
+  assert.equal(canHostService({ ...INSTALLED, hasCore: false }), false);
 });
 
 test("only a loopback HTTP endpoint is a manageable local service", () => {
diff --git a/integrations/dsh/tests/env-service.test.mjs b/integrations/dsh/tests/env-service.test.mjs
index 66bb4ed3..9c4964d4 100644
--- a/integrations/dsh/tests/env-service.test.mjs
+++ b/integrations/dsh/tests/env-service.test.mjs
@@ -1,7 +1,7 @@
 import assert from "node:assert/strict";
 import test from "node:test";
 import { createServer } from "node:http";
-import { mkdtempSync, rmSync } from "node:fs";
+import { mkdtempSync, readFileSync, rmSync } from "node:fs";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
 
@@ -541,6 +541,101 @@ test("refuses to stop a service recorded for another endpoint", async (t) => {
   assert.ok(readServiceState(statePath), "the foreign record is left in place");
 });
 
+for (const exits of [true, false]) {
+  test(`a parent-first exit ${
+    exits ? "waits for" : "retains"
+  } its process group`, async (t) => {
+    const { directory, statePath } = tempState(t, "reme-stop-group-");
+    record(statePath, { pid: 999, workspaceDir: directory });
+    let parent = true;
+    let group = true;
+    const { io, calls } = fakeIO({
+      platform: "linux",
+      processCommandLine: async () => commandFor(statePath),
+      probePid() {
+        if (!parent) throw Object.assign(new Error("gone"), { code: "ESRCH" });
+      },
+      groupAlive: () => group,
+      killTree(pid, force = false) {
+        calls.killTree.push(pid);
+        parent = false;
+        if (force) {
+          calls.force.push(pid);
+          group = !exits;
+        }
+      },
+    });
+    const result = await stopService(io, {
+      statePath,
+      endpoint: ENDPOINT,
+      timeoutMs: 10,
+      forceTimeoutMs: 10,
+      pollMs: 2,
+    });
+    assert.deepEqual(calls.force, [999], "the surviving child gets SIGKILL");
+    assert.equal(result.stopped, exits);
+    if (exits) {
+      assert.equal(readServiceState(statePath), undefined);
+    } else {
+      assert.equal(result.code, "not-exited");
+      const status = await serviceStatus(io, {
+        statePath,
+        endpoint: ENDPOINT,
+        logPath: join(directory, "service.log"),
+      });
+      assert.equal(readServiceState(statePath)?.pid, 999);
+      assert.equal(status.pid, 999);
+      assert.equal(
+        await serviceOwnership(io, readServiceState(statePath), ENDPOINT),
+        "unknown",
+      );
+      // A later stop no longer has a leader whose identity it can verify.
+      const later = await stopService(io, { statePath, endpoint: ENDPOINT });
+      assert.equal(later.code, "unverified");
+      assert.deepEqual(
+        calls.force,
+        [999],
+        "an unverified group is not signalled again",
+      );
+    }
+  });
+}
+
+test("a stop never signals a record replaced during the ownership probe", async (t) => {
+  const { statePath } = tempState(t, "reme-stop-race-");
+  record(statePath);
+  const command = commandFor(statePath);
+  const { io, calls } = fakeIO({
+    processCommandLine: async () => {
+      record(statePath, { pid: 888, startedAt: "new" });
+      return command;
+    },
+  });
+  const result = await stopService(io, { statePath, endpoint: ENDPOINT });
+  assert.equal(result.code, "record-changed");
+  assert.deepEqual(calls.killTree, []);
+  assert.equal(readServiceState(statePath)?.pid, 888);
+});
+
+test("finishing an old stop does not erase a newer service record", async (t) => {
+  const { statePath } = tempState(t, "reme-stop-new-record-");
+  record(statePath);
+  let running = true;
+  const { io } = fakeIO({
+    processCommandLine: async () => commandFor(statePath),
+    probePid() {
+      if (!running) throw Object.assign(new Error("gone"), { code: "ESRCH" });
+    },
+    killTree() {
+      running = false;
+      record(statePath, { pid: 888, startedAt: "new" });
+    },
+  });
+  const result = await stopService(io, { statePath, endpoint: ENDPOINT });
+  assert.equal(result.stopped, true);
+  assert.equal(readServiceState(statePath)?.pid, 888);
+});
+
 test("refuses to stop a process whose identity cannot be verified", async (t) => {
   const { statePath } = tempState(t, "reme-unknown-");
   record(statePath);
@@ -710,3 +805,92 @@ test("real IO spawns, identifies and stops a detached process", async (t) => {
   }
   assert.equal(running, false, "the detached process must actually exit");
 });
+
+test(
+  "real POSIX stop kills a listening child after its parent exits",
+  {
+    skip: process.platform === "win32",
+    timeout: 15_000,
+  },
+  async (t) => {
+    const { directory, statePath } = tempState(t, "reme-real-group-");
+    const io = createServiceIO();
+    const logPath = join(directory, "service.log");
+    const childCode = `
+    process.on('SIGTERM', () => {});
+    const server = require('node:net').createServer(socket => socket.end());
+    server.listen(0, '127.0.0.1', () => {
+      console.log(JSON.stringify({ port: server.address().port, pid: process.pid }));
+    });
+  `;
+    const parentCode = `
+    process.on('SIGTERM', () => process.exit(0));
+    const child = require('node:child_process').spawn(process.execPath,
+      ['-e', ${JSON.stringify(
+        childCode,
+      )}], { stdio: ['ignore', 'pipe', 'ignore'] });
+    child.stdout.pipe(process.stdout);
+  `;
+    const { pid } = await io.spawnService({
+      exe: process.execPath,
+      args: [
+        "-e",
+        parentCode,
+        `workspace_dir=${directory}`,
+        "service.port=2334",
+      ],
+      cwd: directory,
+      logPath,
+      env: process.env,
+    });
+    const kill = io.killTree;
+    t.after(() => kill(pid, true));
+    let ready;
+    const deadline = Date.now() + 5_000;
+    while (!ready && Date.now() < deadline) {
+      try {
+        ready = JSON.parse(readFileSync(logPath, "utf8").trim());
+      } catch {
+        /* not listening yet */
+      }
+      if (!ready) await new Promise((resolve) => setTimeout(resolve, 20));
+    }
+    assert.ok(ready, "the child listener must be ready before signalling");
+    assert.equal(await io.portOpen("127.0.0.1", ready.port), true);
+    record(statePath, { pid, workspaceDir: directory });
+    // The fixture uses Node instead of Python; spawn, command line, signals,
+    // group liveness and socket checks still use the real service adapter.
+    io.processImage = async () => "python";
+    let escalated = false;
+    io.killTree = (target, force) => {
+      if (force) {
+        escalated = true;
+        assert.throws(() => io.probePid(pid), { code: "ESRCH" });
+        assert.doesNotThrow(() => io.probePid(ready.pid));
+      }
+      kill(target, force);
+    };
+    const result = await stopService(io, {
+      statePath,
+      endpoint: ENDPOINT,
+      timeoutMs: 200,
+      forceTimeoutMs: 2_000,
+      pollMs: 20,
+    });
+    assert.equal(
+      escalated,
+      true,
+      "parent exit must not bypass child termination",
+    );
+    assert.equal(await io.portOpen("127.0.0.1", ready.port), false);
+    // Some container init processes leave orphaned zombies unreaped. A group
+    // still visible to signal 0 conservatively retains its record.
+    if (result.stopped) {
+      assert.equal(io.groupAlive(pid), false);
+      assert.equal(readServiceState(statePath), undefined);
+    } else {
+      assert.equal(result.code, "not-exited");
+      assert.equal(readServiceState(statePath)?.pid, pid);
+    }
+  },
+);
diff --git a/integrations/dsh/tests/env-tab.test.mjs b/integrations/dsh/tests/env-tab.test.mjs
index ec3b74f7..530bcd78 100644
--- a/integrations/dsh/tests/env-tab.test.mjs
+++ b/integrations/dsh/tests/env-tab.test.mjs
@@ -230,6 +230,99 @@ test("renders the status hero and the four setup steps", async (t) => {
   assert.match(copy, /C:\\Users\\test\\\.reme\\\.env/);
 });
 
+test("an interpreter without AgentScope cannot offer Start or report ready", async (t) => {
+  const { renderer, restore } = await mount(
+    {},
+    {
+      responses: {
+        "remeEnv/checkReme": {
+          ...RESPONSES["remeEnv/checkReme"],
+          hasCore: false,
+        },
+        "remeEnv/serviceStatus": {
+          ...RESPONSES["remeEnv/serviceStatus"],
+          phase: "stopped",
+          pid: undefined,
+        },
+      },
+    },
+  );
+  t.after(restore);
+  assert.equal(buttonByText(renderer, envZh.startService).props.disabled, true);
+  const copy = texts(renderer.toJSON()).join(" ");
+  assert.ok(copy.includes(envZh.coreMissing));
+  assert.equal(copy.includes(envZh.heroReady), false);
+});
+
+for (const [code, error, expected] of [
+  ["core-missing", "AgentScope missing", envZh.startErrorCoreMissing],
+  ["constructor", "Unknown Host refusal", "Unknown Host refusal"],
+]) {
+  test(`localizes or safely falls back for the ${code} start refusal`, async (t) => {
+    const { renderer, restore } = await mount(
+      {},
+      {
+        responses: {
+          "remeEnv/serviceStatus": {
+            ...RESPONSES["remeEnv/serviceStatus"],
+            phase: "stopped",
+            pid: undefined,
+          },
+          "remeEnv/serviceStart": {
+            started: false,
+            alreadyRunning: false,
+            command: "",
+            logPath: "",
+            startedAt: new Date().toISOString(),
+            code,
+            error,
+          },
+        },
+      },
+    );
+    t.after(restore);
+    await act(async () =>
+      buttonByText(renderer, envZh.startService).props.onClick(),
+    );
+    assert.ok(texts(renderer.toJSON()).join(" ").includes(expected));
+  });
+}
+
+test("an older Host refusal without a record never guesses a Forget target", async (t) => {
+  const { renderer, calls, restore } = await mount(
+    {},
+    {
+      responses: {
+        "remeEnv/serviceStatus": {
+          ...RESPONSES["remeEnv/serviceStatus"],
+          phase: "stopped",
+          pid: undefined,
+        },
+        "remeEnv/serviceStart": {
+          started: false,
+          alreadyRunning: false,
+          command: "",
+          logPath: "",
+          startedAt: new Date().toISOString(),
+          code: "unverified-record",
+        },
+      },
+    },
+  );
+  t.after(restore);
+  await act(async () =>
+    buttonByText(renderer, envZh.startService).props.onClick(),
+  );
+  assert.equal(
+    texts(renderer.toJSON()).join(" ").includes(envZh.forgetRecord),
+    false,
+  );
+  assert.equal(
+    calls.rpc.some((call) => call.method === "remeEnv/serviceForget"),
+    false,
+  );
+});
+
 test("keeps the interpreter list collapsed until asked, then paginates", async (t) => {
   const { renderer, restore } = await mount();
   t.after(restore);
@@ -474,6 +567,7 @@ test("shows why Stop left the service alone", async (t) => {
           stopped: false,
           reason: "The recorded process identity could not be verified",
           code: "unverified",
+          record: { endpoint: "http://127.0.0.1:2333", pid: 98820 },
         },
       },
     },
@@ -514,6 +608,7 @@ test("a process that survived the force-kill still offers forgetting the record"
           stopped: false,
           reason: "The service did not exit after the force-kill",
           code: "not-exited",
+          record: { endpoint: "http://127.0.0.1:2333", pid: 98820 },
         },
       },
     },
@@ -1335,6 +1430,7 @@ test("an unverified record reports the pid it refused to touch", async (t) => {
           alreadyRunning: false,
           error: "The recorded service identity could not be verified",
           code: "unverified-record",
+          record: { endpoint: "http://127.0.0.1:2333", pid: 6000 },
           pid: 6000,
           command: "",
           logPath: stopped.logPath,