diff --git a/config/unidesk-cli.yaml b/config/unidesk-cli.yaml
index 206c0869..25ddb505 100644
--- a/config/unidesk-cli.yaml
+++ b/config/unidesk-cli.yaml
@@ -2,6 +2,7 @@ version: 1
 kind: unidesk-cli
 output:
   maxStdoutBytes: 10240
+  maxPreviewLines: 240
   dumpDir: /tmp/unidesk-cli-output
   includePreview: false
   warning: "CLI stdout exceeded YAML-configured limit; full output was dumped to /tmp for one-off drill-down only. This is a CLI usability defect: improve the command itself to print concise tables/summaries and id-specific progressive disclosure instead of repeatedly depending on dump extraction."
diff --git a/docs/reference/cli.md b/docs/reference/cli.md
index 61ca90f6..52008ca2 100644
--- a/docs/reference/cli.md
+++ b/docs/reference/cli.md
@@ -313,7 +313,7 @@ core 只允许声明了 `host.ssh` capability 的 provider 使用 `host.ssh` dis
 
 ssh-like 远端命令如果出现 `kex_exchange_identification`、`Connection closed by remote host`、provider session timeout 或 exit code 255，CLI 会在原始 stderr 后追加一行 `UNIDESK_SSH_HINT { ... }`。该 JSON 不回显原始远端命令，只包含 `code=ssh-like-command-friction`、`trigger`、`try` 和 `triage`；`try` 固定指向显式 `sh` stdin heredoc 形态，避免把一次 ssh-like 解析/握手摩擦误读成 D601 SSH 整体不可用。`ssh`/`trans`/`tran` 在失败路径识别到 tcp-pool 数据面问题时会追加 `UNIDESK_SSH_TCP_POOL_HINT { ... }`，`failureKind` 固定分为 `provider-data-channel-closed`、`provider-data-channel-missing` 和 `provider-data-pool-exhausted`；这类 hint 表示 transport/data-pool transient，幂等受控操作应先运行 `bun scripts/cli.ts debug ssh-pool <providerId>` 查看 labels，再重试原受控 CLI，不能单独定性为远端 runtime 配置失败。backend-core/provider 控制面返回结构化 `ssh.error` 时 broker 还会输出 `UNIDESK_SSH_ERROR { ... }`，供 `job status` 从旧日志或异步 job 日志中恢复 failureKind。`ssh`/`trans`/`tran` 运行时硬超时会输出 `UNIDESK_SSH_RUNTIME_TIMEOUT { ... }` 或 wrapper 层 `UNIDESK_TRAN_TIMEOUT_HINT { ... }`；这不是远端业务失败，而是调用方需要改成短查询/轮询。`ssh`/`trans`/`tran` 只有在运行耗时超过默认 10000ms 时才会在 stderr 追加一行 `UNIDESK_SSH_TIMING { ... }`，且 `level=warning`；正常短调用不输出 timing 噪声。慢成功命令也必须保留该 warning，因为它是 provider session、远端命令成本、helper bootstrap 和 `trans`/`tran`/远端 patch 性能回归的重要监控信号。warning 包含 `elapsedMs`、`elapsedSeconds`、`transport`、`invocationKind` 和 `exitCode`，提示优先排查 provider/session 延迟、远端命令自身耗时、helper bootstrap 或工具层回归。阈值可用 `UNIDESK_SSH_SLOW_WARNING_MS=<ms>` 临时调节，提示同样不回显原始远端命令。
 
-非交互 `ssh`/`trans`/`tran` 远端命令的流式 stdout 默认有本地输出上限，避免远端日志、PowerShell JSON 或错误对象一次性输出过大导致上下文被淹没；交互登录 shell 不套该上限。超过上限时，CLI 只继续读取远端流并把完整内容写入 `/tmp/unidesk-cli-output/*.stdout.bin`，本地 stderr 追加 `UNIDESK_SSH_STDOUT_TRUNCATED { ... }`，其中包含 `thresholdBytes`、`observedBytesAtTruncation`、`dumpPath` 和 `dumpError`；stdout 本身只保留上限内的开头内容。默认上限是 256KiB，可用 `UNIDESK_SSH_STDOUT_STREAM_MAX_BYTES=<bytes>` 或 `UNIDESK_TRAN_STDOUT_STREAM_MAX_BYTES=<bytes>` 临时调整，最小 4KiB，最大 16MiB。该机制只做渐进披露和完整 dump，不替代远端命令失败判断；看到该 hint 时应优先改成 `tail`、分页或更窄的结构化查询。
+非交互 `ssh`/`trans`/`tran` 远端命令的流式 stdout/stderr 服从统一 CLI dump/preview 策略，默认预览预算来自 `config/unidesk-cli.yaml#output.maxStdoutBytes` 和 `#output.maxPreviewLines`，完整流写入同一 YAML 声明的 dump 目录；交互登录 shell 不套该上限。超过预算时，CLI 继续读取远端流并把完整内容写入 `/tmp/unidesk-cli-output/*.stdout.bin` 或 `*.stderr.bin`，本地 stderr 追加 `UNIDESK_SSH_STDOUT_TRUNCATED { ... }` 或 `UNIDESK_SSH_STDERR_TRUNCATED { ... }`，其中包含 `stream`、`trigger`、`thresholdBytes`、`thresholdLines`、`forwardedBytes`、`forwardedLines`、`observedBytesAtTruncation`、`observedLinesAtTruncation`、`dumpPath`、`dumpError`、`disclosurePolicy` 和 `recommendedRerun`；被截断的本地流只保留 YAML 预算内的开头预览。需要一次性扩大字节预算时可显式设置 `UNIDESK_SSH_STDOUT_STREAM_MAX_BYTES` / `UNIDESK_TRAN_STDOUT_STREAM_MAX_BYTES` 或 `UNIDESK_SSH_STDERR_STREAM_MAX_BYTES` / `UNIDESK_TRAN_STDERR_STREAM_MAX_BYTES`，仍受最小 4KiB、最大 16MiB 的工具保护。该机制只做渐进披露和完整 dump，不替代远端命令失败判断；看到 hint 时应优先改成 `rg -m`、`sed -n`、`tail`、`--limit`、`--tail-bytes`、`--raw/--full` 等更窄的结构化 drill-down。
 
 `trans <providerId>` 透传只在当前 operation 需要 helper 时才注入 `/tmp/unidesk-ssh-tools`，普通 `argv`、`sh`/`bash`、`kubectl`、`logs` 和默认 `apply-patch` 等路径不得传输无关工具源码。`apply-patch-v1` 只注入 `apply_patch`；`glob` 只注入 `glob`；`skills`/`skill discover` 只注入 `skill-discover`。`apply_patch` 接受标准 `*** Begin Patch` / `*** End Patch` patch 格式，便于通过 SSH 透传编辑远端仓库文件；远端存在 `perl` 时必须走快速精确匹配路径，避免大文件 hunk 被 sh 模式匹配拖成几十秒，缺少 `perl` 时才退回 sh-only 实现。`glob` 和 `skill-discover` 需要远端 `python3`。注入工具只写 `/tmp/unidesk-ssh-tools`，不修改目标仓库。
 
diff --git a/scripts/src/output.ts b/scripts/src/output.ts
index cc47b543..2327d474 100644
--- a/scripts/src/output.ts
+++ b/scripts/src/output.ts
@@ -23,8 +23,9 @@ const CLI_OUTPUT_CONFIG_PATH = rootPath("config", "unidesk-cli.yaml");
 const EMERGENCY_OUTPUT_DUMP_THRESHOLD_BYTES = 10 * 1024;
 const EMERGENCY_OUTPUT_DUMP_DIR = join(tmpdir(), "unidesk-cli-output");
 
-interface CliOutputPolicy {
+export interface CliOutputPolicy {
   maxStdoutBytes: number;
+  maxPreviewLines: number;
   dumpDir: string;
   includePreview: boolean;
   warning: string;
@@ -71,6 +72,10 @@ export function emitError(command: string, error: unknown): void {
   safeStdoutWrite(renderEnvelope(command, envelope));
 }
 
+export function readCliOutputPolicy(): CliOutputPolicy {
+  return cliOutputPolicy();
+}
+
 function normalizeErrorPayload(command: string, error: unknown): Record<string, unknown> {
   const message = error instanceof Error ? error.message : String(error);
   const parsed = parseStructuredErrorMessage(command, message);
@@ -141,16 +146,18 @@ function shouldSuppressStack(prefix: string): boolean {
 
 function renderEnvelope<T>(command: string, envelope: JsonEnvelope<T>): string {
   const fullText = `${JSON.stringify(envelope, null, 2)}\n`;
-  if (!shouldDumpLargeOutput(command, fullText, envelope)) return fullText;
-
   const policy = cliOutputPolicy();
+  const trigger = outputDumpTrigger(fullText, policy, "json");
+  if (trigger === null) return fullText;
+
   const dump = dumpLargeOutput(command, fullText, "json", policy);
   const compactPayload = {
     outputTruncated: true,
-    reason: "stdout-json-exceeded-threshold",
+    reason: trigger.reason,
     warning: policy.warning,
     message: "Full JSON output was written to a temporary file; stdout contains only file metadata and a compact summary.",
     disclosurePolicy: disclosurePolicy(policy),
+    trigger,
     dump,
     summary: summarizeEnvelope(envelope),
   };
@@ -160,29 +167,47 @@ function renderEnvelope<T>(command: string, envelope: JsonEnvelope<T>): string {
   return `${JSON.stringify(compactEnvelope, null, 2)}\n`;
 }
 
-function shouldDumpLargeOutput(command: string, text: string, envelope: JsonEnvelope<unknown>): boolean {
-  void command;
-  void envelope;
-  if (process.env.UNIDESK_CLI_OUTPUT_DUMP_DISABLED === "1") return false;
-  const threshold = cliOutputPolicy().maxStdoutBytes;
-  return Buffer.byteLength(text, "utf8") > threshold;
+function outputDumpTrigger(text: string, policy: CliOutputPolicy, content: "json" | "text"): Record<string, unknown> | null {
+  if (process.env.UNIDESK_CLI_OUTPUT_DUMP_DISABLED === "1") return null;
+  const bytes = Buffer.byteLength(text, "utf8");
+  const lines = countLines(text);
+  if (bytes > policy.maxStdoutBytes) {
+    return {
+      reason: `stdout-${content}-bytes-exceeded-threshold`,
+      thresholdBytes: policy.maxStdoutBytes,
+      observedBytes: bytes,
+      thresholdLines: policy.maxPreviewLines,
+      observedLines: lines,
+    };
+  }
+  if (lines > policy.maxPreviewLines) {
+    return {
+      reason: `stdout-${content}-lines-exceeded-threshold`,
+      thresholdBytes: policy.maxStdoutBytes,
+      observedBytes: bytes,
+      thresholdLines: policy.maxPreviewLines,
+      observedLines: lines,
+    };
+  }
+  return null;
 }
 
 function renderTextOutput(command: string, text: string): string {
   const fullText = text.endsWith("\n") ? text : `${text}\n`;
-  if (process.env.UNIDESK_CLI_OUTPUT_DUMP_DISABLED === "1") return fullText;
   const policy = cliOutputPolicy();
-  if (Buffer.byteLength(fullText, "utf8") <= policy.maxStdoutBytes) return fullText;
+  const trigger = outputDumpTrigger(fullText, policy, "text");
+  if (trigger === null) return fullText;
   const dump = dumpLargeOutput(command, fullText, "txt", policy);
   const payload: JsonEnvelope<Record<string, unknown>> = {
     ok: true,
     command,
     data: {
       outputTruncated: true,
-      reason: "stdout-text-exceeded-threshold",
+      reason: trigger.reason,
       warning: policy.warning,
       message: "Full text output was written to a temporary file; stdout contains only file metadata.",
       disclosurePolicy: disclosurePolicy(policy),
+      trigger,
       dump,
     },
   };
@@ -200,6 +225,7 @@ function dumpLargeOutput(command: string, text: string, extension: "json" | "txt
     path,
     configPath: policy.configPath,
     thresholdBytes: policy.maxStdoutBytes,
+    thresholdLines: policy.maxPreviewLines,
     bytes: Buffer.byteLength(text, "utf8"),
     chars: text.length,
     lines: countLines(text),
@@ -292,6 +318,7 @@ function disclosurePolicy(policy: CliOutputPolicy): Record<string, unknown> {
   return {
     configPath: policy.configPath,
     maxStdoutBytes: policy.maxStdoutBytes,
+    maxPreviewLines: policy.maxPreviewLines,
     dumpDir: policy.dumpDir,
     includePreview: policy.includePreview,
     recommendation: "Prefer k8s-style concise summaries/tables by default; expose full data through explicit --full/--raw/id-specific drill-down commands instead of large stdout.",
@@ -520,6 +547,7 @@ function cliOutputPolicy(): CliOutputPolicy {
     const output = objectField(root, "output", CLI_OUTPUT_CONFIG_RELATIVE_PATH);
     cachedOutputPolicy = {
       maxStdoutBytes: positiveIntegerField(output, "maxStdoutBytes", `${CLI_OUTPUT_CONFIG_RELATIVE_PATH}.output`),
+      maxPreviewLines: positiveIntegerField(output, "maxPreviewLines", `${CLI_OUTPUT_CONFIG_RELATIVE_PATH}.output`),
       dumpDir: absolutePathField(output, "dumpDir", `${CLI_OUTPUT_CONFIG_RELATIVE_PATH}.output`),
       includePreview: booleanField(output, "includePreview", `${CLI_OUTPUT_CONFIG_RELATIVE_PATH}.output`),
       warning: stringField(output, "warning", `${CLI_OUTPUT_CONFIG_RELATIVE_PATH}.output`),
@@ -530,6 +558,7 @@ function cliOutputPolicy(): CliOutputPolicy {
     const message = error instanceof Error ? error.message : String(error);
     cachedOutputPolicy = {
       maxStdoutBytes: EMERGENCY_OUTPUT_DUMP_THRESHOLD_BYTES,
+      maxPreviewLines: 240,
       dumpDir: EMERGENCY_OUTPUT_DUMP_DIR,
       includePreview: false,
       warning: "CLI output policy YAML could not be loaded; emergency dump guard is active for one-off drill-down only. Fix config/unidesk-cli.yaml, then improve the noisy command itself to print concise tables/summaries and id-specific progressive disclosure instead of repeatedly depending on dump extraction.",
diff --git a/scripts/src/remote-ssh.ts b/scripts/src/remote-ssh.ts
index 58ac1f2c..c9ca5acf 100644
--- a/scripts/src/remote-ssh.ts
+++ b/scripts/src/remote-ssh.ts
@@ -9,6 +9,7 @@ import {
   buildWindowsPowerShellInvocation,
   createPosixApplyPatchFileSystem,
   createWindowsApplyPatchFileSystem,
+  createSshStderrForwarder,
   createSshStdoutForwarder,
   formatSshFailureHint,
   formatSshRuntimeTimeoutHint,
@@ -382,6 +383,10 @@ async function runRemoteSshWebSocket(
       invocation,
       transport: "frontend-websocket",
     });
+    const stderrForwarder = parsed.remoteCommand === null ? null : createSshStderrForwarder({
+      invocation,
+      transport: "frontend-websocket",
+    });
     let timedOut = false;
     const openTimer = setTimeout(() => {
       if (sessionReady || settled) return;
@@ -464,8 +469,14 @@ async function runRemoteSshWebSocket(
       }
       if (message.type === "ssh.data") {
         const chunk = Buffer.from(String(message.data ?? ""), message.encoding === "base64" ? "base64" : "utf8");
-        if (message.stream === "stderr") process.stderr.write(chunk);
-        else if (stdoutForwarder === null) {
+        if (message.stream === "stderr") {
+          if (stderrForwarder === null) {
+            process.stderr.write(chunk);
+          } else {
+            const hint = stderrForwarder.write(chunk);
+            if (hint !== null) process.stderr.write(hint);
+          }
+        } else if (stdoutForwarder === null) {
           process.stdout.write(chunk);
         } else {
           const hint = stdoutForwarder.write(chunk);
diff --git a/scripts/src/remote.ts b/scripts/src/remote.ts
index 2ba1b93e..e6330b9f 100644
--- a/scripts/src/remote.ts
+++ b/scripts/src/remote.ts
@@ -10,6 +10,7 @@ import {
   buildWindowsPowerShellInvocation,
   createPosixApplyPatchFileSystem,
   createWindowsApplyPatchFileSystem,
+  createSshStderrForwarder,
   createSshStdoutForwarder,
   formatSshFailureHint,
   formatSshRuntimeTimeoutHint,
@@ -1019,6 +1020,10 @@ async function runRemoteSshWebSocket(
       invocation,
       transport: "frontend-websocket",
     });
+    const stderrForwarder = parsed.remoteCommand === null ? null : createSshStderrForwarder({
+      invocation,
+      transport: "frontend-websocket",
+    });
     let timedOut = false;
     const openTimer = setTimeout(() => {
       if (sessionReady || settled) return;
@@ -1101,8 +1106,14 @@ async function runRemoteSshWebSocket(
       }
       if (message.type === "ssh.data") {
         const chunk = Buffer.from(String(message.data ?? ""), message.encoding === "base64" ? "base64" : "utf8");
-        if (message.stream === "stderr") process.stderr.write(chunk);
-        else if (stdoutForwarder === null) {
+        if (message.stream === "stderr") {
+          if (stderrForwarder === null) {
+            process.stderr.write(chunk);
+          } else {
+            const hint = stderrForwarder.write(chunk);
+            if (hint !== null) process.stderr.write(hint);
+          }
+        } else if (stdoutForwarder === null) {
           process.stdout.write(chunk);
         } else {
           const hint = stdoutForwarder.write(chunk);
diff --git a/scripts/src/ssh.test.ts b/scripts/src/ssh.test.ts
index aa975b65..adbad403 100644
--- a/scripts/src/ssh.test.ts
+++ b/scripts/src/ssh.test.ts
@@ -1,20 +1,23 @@
 import { createHash } from "node:crypto";
-import { mkdtempSync, rmSync, writeFileSync } from "node:fs";
+import { mkdtempSync, readFileSync, rmSync, writeFileSync } from "node:fs";
 import { join } from "node:path";
 import { tmpdir } from "node:os";
 import { describe, expect, test } from "bun:test";
 import type { UniDeskConfig } from "./config";
 import {
   createPosixApplyPatchFileSystem,
+  createSshStderrForwarder,
   createSshStdoutForwarder,
   formatSshStdoutTruncationHint,
   parseSshInvocation,
   sshCaptureBackendPlan,
+  sshStderrStreamMaxBytes,
   sshStdoutStreamMaxBytes,
   sshStdoutTruncationHint,
   windowsFsReadOnlyScript,
   windowsPowerShellScriptPrelude,
 } from "./ssh";
+import { readCliOutputPolicy } from "./output";
 
 function sha256Hex(text: string): string {
   return createHash("sha256").update(text, "utf8").digest("hex");
@@ -150,14 +153,18 @@ describe("ssh host apply-patch fs backend", () => {
 });
 
 describe("ssh stdout bounded streaming", () => {
-  test("uses bounded defaults and clamps env override", () => {
-    expect(sshStdoutStreamMaxBytes({} as NodeJS.ProcessEnv)).toBe(256 * 1024);
+  test("uses YAML output policy defaults and clamps env override", () => {
+    const policy = readCliOutputPolicy();
+    expect(sshStdoutStreamMaxBytes({} as NodeJS.ProcessEnv)).toBe(policy.maxStdoutBytes);
+    expect(sshStderrStreamMaxBytes({} as NodeJS.ProcessEnv)).toBe(policy.maxStdoutBytes);
     expect(sshStdoutStreamMaxBytes({ UNIDESK_SSH_STDOUT_STREAM_MAX_BYTES: "8192" } as NodeJS.ProcessEnv)).toBe(8192);
+    expect(sshStderrStreamMaxBytes({ UNIDESK_SSH_STDERR_STREAM_MAX_BYTES: "8192" } as NodeJS.ProcessEnv)).toBe(8192);
     expect(sshStdoutStreamMaxBytes({ UNIDESK_SSH_STDOUT_STREAM_MAX_BYTES: "1" } as NodeJS.ProcessEnv)).toBe(4096);
     expect(sshStdoutStreamMaxBytes({ UNIDESK_SSH_STDOUT_STREAM_MAX_BYTES: String(64 * 1024 * 1024) } as NodeJS.ProcessEnv)).toBe(16 * 1024 * 1024);
   });
 
   test("formats truncation hint without echoing remote command", () => {
+    const policy = readCliOutputPolicy();
     const invocation = parseSshInvocation("D601:win", ["ps"]);
     expect(invocation.parsed.remoteCommand).not.toBeNull();
     const hint = sshStdoutTruncationHint({
@@ -175,6 +182,11 @@ describe("ssh stdout bounded streaming", () => {
     expect(payload.providerId).toBe("D601");
     expect(payload.route).toBe("D601:win");
     expect(payload.thresholdBytes).toBe(4096);
+    expect(payload.disclosurePolicy).toMatchObject({
+      name: "unified-cli-dump-preview",
+      configPath: "config/unidesk-cli.yaml",
+    });
+    expect(payload.thresholdLines).toBe(policy.maxPreviewLines);
     expect(formatted).not.toContain("Get-Content");
   });
 
@@ -201,6 +213,58 @@ describe("ssh stdout bounded streaming", () => {
     expect(Buffer.concat(forwarded).toString("utf8")).toBe("abcde");
     expect(hint).toContain("UNIDESK_SSH_STDOUT_TRUNCATED");
     expect(hint).toContain("\"transport\":\"frontend-websocket\"");
+    expect(hint).toContain("\"forwardedBytes\":5");
+    const payload = JSON.parse(hint!.slice("UNIDESK_SSH_STDOUT_TRUNCATED ".length)) as { dumpPath: string };
+    expect(readFileSync(payload.dumpPath, "utf8")).toBe("abcdefghijkl");
+    rmSync(payload.dumpPath, { force: true });
+  });
+
+  test("forwarder bounds very short lines by YAML-style line budget", () => {
+    const invocation = parseSshInvocation("D601:win", ["ps"]);
+    const forwarded: Buffer[] = [];
+    const stdout = {
+      write(chunk: string | Buffer): boolean {
+        forwarded.push(Buffer.isBuffer(chunk) ? chunk : Buffer.from(chunk));
+        return true;
+      },
+    } as NodeJS.WritableStream;
+    const forwarder = createSshStdoutForwarder({
+      invocation,
+      transport: "frontend-websocket",
+      maxBytes: 1000,
+      maxLines: 2,
+      stdout,
+    });
+
+    const hint = forwarder.write(Buffer.from("a\nb\nc\n"));
+    expect(Buffer.concat(forwarded).toString("utf8")).toBe("a\nb\n");
+    expect(hint).toContain("\"trigger\":\"lines\"");
+    const payload = JSON.parse(hint!.slice("UNIDESK_SSH_STDOUT_TRUNCATED ".length)) as { dumpPath: string; forwardedLines: number };
+    expect(payload.forwardedLines).toBe(2);
+    expect(readFileSync(payload.dumpPath, "utf8")).toBe("a\nb\nc\n");
+    rmSync(payload.dumpPath, { force: true });
+  });
+
+  test("stderr forwarder uses the same dump guard and marker", () => {
+    const invocation = parseSshInvocation("D601:win", ["ps"]);
+    const forwarded: Buffer[] = [];
+    const stderr = {
+      write(chunk: string | Buffer): boolean {
+        forwarded.push(Buffer.isBuffer(chunk) ? chunk : Buffer.from(chunk));
+        return true;
+      },
+    } as NodeJS.WritableStream;
+    const forwarder = createSshStderrForwarder({
+      invocation,
+      transport: "backend-core-broker",
+      maxBytes: 4,
+      stderr,
+    });
+
+    const hint = forwarder.write(Buffer.from("abcdef"));
+    expect(Buffer.concat(forwarded).toString("utf8")).toBe("abcd");
+    expect(hint).toContain("UNIDESK_SSH_STDERR_TRUNCATED");
+    expect(hint).toContain("\"stream\":\"stderr\"");
   });
 });
 
diff --git a/scripts/src/ssh.ts b/scripts/src/ssh.ts
index a36c7eed..e1323cc1 100644
--- a/scripts/src/ssh.ts
+++ b/scripts/src/ssh.ts
@@ -1,7 +1,6 @@
 import { spawn, spawnSync } from "node:child_process";
 import { createHash, randomBytes } from "node:crypto";
 import { appendFileSync, mkdirSync, writeFileSync } from "node:fs";
-import { tmpdir } from "node:os";
 import { join } from "node:path";
 import { type UniDeskConfig, repoRoot } from "./config";
 import {
@@ -24,6 +23,7 @@ import {
 } from "./ssh-file-transfer";
 import { readTransHostProxyEnvRule, type TransHostProxyEnvRule } from "./trans-host-proxy";
 import { readTransSshBackendConfig, type TransSshBackendConfig } from "./trans-config";
+import { readCliOutputPolicy } from "./output";
 
 export interface ParsedSshArgs {
   remoteCommand: string | null;
@@ -151,16 +151,30 @@ export class SshRemovedShellAliasError extends Error {
 }
 
 export interface SshStdoutTruncationHint {
-  code: "ssh-stdout-truncated";
+  code: "ssh-stdout-truncated" | "ssh-stderr-truncated";
   level: "warning";
+  stream: "stdout" | "stderr";
   providerId: string;
   route: string;
   transport: "backend-core-broker" | "frontend-websocket";
   invocationKind: SshInvocationKind;
   thresholdBytes: number;
+  thresholdLines: number;
+  trigger: "bytes" | "lines" | "bytes-and-lines";
   observedBytesAtTruncation: number;
+  forwardedBytes: number;
+  observedLinesAtTruncation: number;
+  forwardedLines: number;
   dumpPath: string | null;
   dumpError: string | null;
+  disclosurePolicy: {
+    name: "unified-cli-dump-preview";
+    configPath: string;
+    maxPreviewBytes: number;
+    maxPreviewLines: number;
+    dumpDir: string;
+  };
+  recommendedRerun: string[];
   message: string;
   action: string;
   note: string;
@@ -200,10 +214,8 @@ const defaultSshRuntimeTimeoutMs = 60_000;
 const maxSshRuntimeTimeoutMs = 60_000;
 const defaultSshBackendCoreDetectTimeoutMs = 15_000;
 const maxSshBackendCoreDetectTimeoutMs = 60_000;
-const defaultSshStdoutStreamMaxBytes = 256 * 1024;
 const minSshStdoutStreamMaxBytes = 4 * 1024;
 const maxSshStdoutStreamMaxBytes = 16 * 1024 * 1024;
-const sshStdoutDumpDir = join(tmpdir(), "unidesk-cli-output");
 export const sshShellCompatibilityPrelude = 'printf(){ if [ "${1+x}" = x ] && [ "$1" = "-v" ] && [ -n "${BASH_VERSION:-}" ]; then command printf "$@"; return $?; fi; if [ "${1+x}" = x ] && [ "$1" = "--" ]; then shift; fi; command printf -- "$@"; }';
 export const sshUserToolPathPrelude = [
   'for unidesk_path_dir in "$HOME/.bun/bin" "$HOME/.local/bin" "$HOME/bin" "/root/.bun/bin"; do',
@@ -2653,37 +2665,71 @@ export function formatSshRuntimeTimeoutHint(hint: SshRuntimeTimeoutHint): string
 export function sshStdoutStreamMaxBytes(env: NodeJS.ProcessEnv = process.env): number {
   const raw = env.UNIDESK_SSH_STDOUT_STREAM_MAX_BYTES ?? env.UNIDESK_TRAN_STDOUT_STREAM_MAX_BYTES;
   const parsed = raw === undefined ? NaN : Number(raw);
-  if (!Number.isFinite(parsed) || parsed <= 0) return defaultSshStdoutStreamMaxBytes;
+  if (!Number.isFinite(parsed) || parsed <= 0) return readCliOutputPolicy().maxStdoutBytes;
+  return Math.min(maxSshStdoutStreamMaxBytes, Math.max(minSshStdoutStreamMaxBytes, Math.trunc(parsed)));
+}
+
+export function sshStderrStreamMaxBytes(env: NodeJS.ProcessEnv = process.env): number {
+  const raw = env.UNIDESK_SSH_STDERR_STREAM_MAX_BYTES ?? env.UNIDESK_TRAN_STDERR_STREAM_MAX_BYTES;
+  const parsed = raw === undefined ? NaN : Number(raw);
+  if (!Number.isFinite(parsed) || parsed <= 0) return readCliOutputPolicy().maxStdoutBytes;
   return Math.min(maxSshStdoutStreamMaxBytes, Math.max(minSshStdoutStreamMaxBytes, Math.trunc(parsed)));
 }
 
 export function sshStdoutTruncationHint(options: {
   invocation: ParsedSshInvocation;
   transport: SshStdoutTruncationHint["transport"];
+  stream?: SshStdoutTruncationHint["stream"];
   thresholdBytes: number;
+  thresholdLines?: number;
+  trigger?: SshStdoutTruncationHint["trigger"];
   observedBytesAtTruncation: number;
+  forwardedBytes?: number;
+  observedLinesAtTruncation?: number;
+  forwardedLines?: number;
   dumpPath: string | null;
   dumpError?: string | null;
 }): SshStdoutTruncationHint {
+  const stream = options.stream ?? "stdout";
+  const policy = readCliOutputPolicy();
   return {
-    code: "ssh-stdout-truncated",
+    code: stream === "stdout" ? "ssh-stdout-truncated" : "ssh-stderr-truncated",
     level: "warning",
+    stream,
     providerId: safeProviderId(options.invocation.providerId),
     route: options.invocation.route.raw,
     transport: options.transport,
     invocationKind: options.invocation.parsed.invocationKind,
     thresholdBytes: options.thresholdBytes,
+    thresholdLines: options.thresholdLines ?? policy.maxPreviewLines,
+    trigger: options.trigger ?? "bytes",
     observedBytesAtTruncation: options.observedBytesAtTruncation,
+    forwardedBytes: options.forwardedBytes ?? Math.min(options.thresholdBytes, options.observedBytesAtTruncation),
+    observedLinesAtTruncation: options.observedLinesAtTruncation ?? 0,
+    forwardedLines: options.forwardedLines ?? 0,
     dumpPath: options.dumpPath,
     dumpError: options.dumpError ?? null,
-    message: `ssh stdout exceeded ${options.thresholdBytes} bytes; stdout is bounded and the complete stream is written to a local dump when possible.`,
-    action: "Inspect the dump path, or rerun a narrower remote command with tail/paging instead of emitting full logs or huge JSON.",
+    disclosurePolicy: {
+      name: "unified-cli-dump-preview",
+      configPath: policy.configPath,
+      maxPreviewBytes: policy.maxStdoutBytes,
+      maxPreviewLines: policy.maxPreviewLines,
+      dumpDir: policy.dumpDir,
+    },
+    recommendedRerun: [
+      "Use rg -m/--max-count, sed -n, head, tail, --limit, --tail-bytes, or an id-specific query.",
+      "Use --full, --raw, --tail-bytes, --limit, or UNIDESK_*_STREAM_MAX_BYTES only when you intentionally need a wider one-off disclosure.",
+      "Read the dumpPath for the complete captured stream.",
+    ],
+    message: `ssh ${stream} exceeded the YAML-configured preview budget; ${stream} is bounded and the complete stream is written to a local dump when possible.`,
+    action: "Inspect dumpPath for the complete stream, or rerun a narrower remote command instead of emitting full logs, huge JSON, or broad search output.",
     note: "This hint is written to stderr and intentionally does not echo the original remote command.",
   };
 }
 
 export function formatSshStdoutTruncationHint(hint: SshStdoutTruncationHint): string {
-  return `UNIDESK_SSH_STDOUT_TRUNCATED ${JSON.stringify(hint)}\n`;
+  const marker = hint.stream === "stderr" ? "UNIDESK_SSH_STDERR_TRUNCATED" : "UNIDESK_SSH_STDOUT_TRUNCATED";
+  return `${marker} ${JSON.stringify(hint)}\n`;
 }
 
 export function classifySshTcpPoolFailure(text: string): SshTcpPoolFailureKind | null {
@@ -2739,27 +2785,66 @@ export function formatSshTcpPoolHint(hint: SshTcpPoolHint | null): string {
   return hint === null ? "" : `UNIDESK_SSH_TCP_POOL_HINT ${JSON.stringify(hint)}\n`;
 }
 
-function sshStdoutDumpPath(invocation: ParsedSshInvocation): string {
-  mkdirSync(sshStdoutDumpDir, { recursive: true, mode: 0o700 });
+function sshStreamDumpPath(invocation: ParsedSshInvocation, stream: SshStdoutTruncationHint["stream"]): string {
+  const policy = readCliOutputPolicy();
+  mkdirSync(policy.dumpDir, { recursive: true, mode: 0o700 });
   const timestamp = new Date().toISOString().replace(/[:.]/gu, "-");
   const suffix = randomBytes(4).toString("hex");
   const slug = `${invocation.providerId}-${invocation.route.raw}-${invocation.route.plane}`
     .replace(/[^A-Za-z0-9._-]+/gu, "-")
     .replace(/^-+|-+$/gu, "")
     .slice(0, 80) || "ssh";
-  return join(sshStdoutDumpDir, `${timestamp}-${process.pid}-${suffix}-${slug}.stdout.bin`);
+  return join(policy.dumpDir, `${timestamp}-${process.pid}-${suffix}-${slug}.${stream}.bin`);
 }
 
 export function createSshStdoutForwarder(options: {
   invocation: ParsedSshInvocation;
   transport: SshStdoutTruncationHint["transport"];
   maxBytes?: number;
+  maxLines?: number;
   stdout?: NodeJS.WritableStream;
 }): { write: (chunk: Buffer) => string | null } {
-  const stdout = options.stdout ?? process.stdout;
-  const maxBytes = options.maxBytes ?? sshStdoutStreamMaxBytes();
+  return createSshStreamForwarder({
+    invocation: options.invocation,
+    transport: options.transport,
+    stream: "stdout",
+    maxBytes: options.maxBytes ?? sshStdoutStreamMaxBytes(),
+    maxLines: options.maxLines ?? readCliOutputPolicy().maxPreviewLines,
+    target: options.stdout ?? process.stdout,
+  });
+}
+
+export function createSshStderrForwarder(options: {
+  invocation: ParsedSshInvocation;
+  transport: SshStdoutTruncationHint["transport"];
+  maxBytes?: number;
+  maxLines?: number;
+  stderr?: NodeJS.WritableStream;
+}): { write: (chunk: Buffer) => string | null } {
+  return createSshStreamForwarder({
+    invocation: options.invocation,
+    transport: options.transport,
+    stream: "stderr",
+    maxBytes: options.maxBytes ?? sshStderrStreamMaxBytes(),
+    maxLines: options.maxLines ?? readCliOutputPolicy().maxPreviewLines,
+    target: options.stderr ?? process.stderr,
+  });
+}
+
+function createSshStreamForwarder(options: {
+  invocation: ParsedSshInvocation;
+  transport: SshStdoutTruncationHint["transport"];
+  stream: SshStdoutTruncationHint["stream"];
+  maxBytes: number;
+  maxLines: number;
+  target: NodeJS.WritableStream;
+}): { write: (chunk: Buffer) => string | null } {
   let observedBytes = 0;
   let forwardedBytes = 0;
+  let observedLineBreaks = 0;
+  let forwardedLineBreaks = 0;
+  let observedEndsWithLineBreak = false;
+  let forwardedEndsWithLineBreak = false;
   let truncated = false;
   let dumpPath: string | null = null;
   let dumpError: string | null = null;
@@ -2769,7 +2854,7 @@ export function createSshStdoutForwarder(options: {
     if (dumpError !== null) return;
     try {
       if (dumpPath === null) {
-        dumpPath = sshStdoutDumpPath(options.invocation);
+        dumpPath = sshStreamDumpPath(options.invocation, options.stream);
         writeFileSync(dumpPath, Buffer.alloc(0), { mode: 0o600 });
         for (const buffered of bufferedChunks) appendFileSync(dumpPath, buffered);
         bufferedChunks.length = 0;
@@ -2784,26 +2869,48 @@ export function createSshStdoutForwarder(options: {
   return {
     write(chunk: Buffer): string | null {
       observedBytes += chunk.length;
-      if (!truncated && observedBytes <= maxBytes) {
+      observedLineBreaks += countBufferLineBreaks(chunk);
+      if (chunk.length > 0) observedEndsWithLineBreak = chunk[chunk.length - 1] === 10;
+      const observedLines = lineCountFromBreaks(observedBytes, observedLineBreaks, observedEndsWithLineBreak);
+      if (!truncated && observedBytes <= options.maxBytes && observedLines <= options.maxLines) {
         bufferedChunks.push(Buffer.from(chunk));
-        stdout.write(chunk);
+        options.target.write(chunk);
         forwardedBytes += chunk.length;
+        forwardedLineBreaks += countBufferLineBreaks(chunk);
+        if (chunk.length > 0) forwardedEndsWithLineBreak = chunk[chunk.length - 1] === 10;
         return null;
       }
 
       if (!truncated) {
         truncated = true;
-        const remaining = Math.max(0, maxBytes - forwardedBytes);
+        const remainingByBytes = Math.max(0, options.maxBytes - forwardedBytes);
+        const remainingByLines = prefixLengthWithinLineBudget(
+          chunk,
+          forwardedBytes,
+          forwardedLineBreaks,
+          forwardedEndsWithLineBreak,
+          options.maxLines,
+        );
+        const remaining = Math.min(remainingByBytes, remainingByLines);
         if (remaining > 0) {
-          stdout.write(chunk.subarray(0, remaining));
+          const forwarded = chunk.subarray(0, remaining);
+          options.target.write(forwarded);
           forwardedBytes += remaining;
+          forwardedLineBreaks += countBufferLineBreaks(forwarded);
+          if (forwarded.length > 0) forwardedEndsWithLineBreak = forwarded[forwarded.length - 1] === 10;
         }
         appendDump(chunk);
         return formatSshStdoutTruncationHint(sshStdoutTruncationHint({
           invocation: options.invocation,
           transport: options.transport,
-          thresholdBytes: maxBytes,
+          stream: options.stream,
+          thresholdBytes: options.maxBytes,
+          thresholdLines: options.maxLines,
+          trigger: sshStreamTruncationTrigger(observedBytes, observedLines, options.maxBytes, options.maxLines),
           observedBytesAtTruncation: observedBytes,
+          forwardedBytes,
+          observedLinesAtTruncation: lineCountFromBreaks(observedBytes, observedLineBreaks, observedEndsWithLineBreak),
+          forwardedLines: lineCountFromBreaks(forwardedBytes, forwardedLineBreaks, forwardedEndsWithLineBreak),
           dumpPath,
           dumpError,
         }));
@@ -2815,6 +2922,51 @@ export function createSshStdoutForwarder(options: {
   };
 }
 
+function countBufferLineBreaks(buffer: Buffer): number {
+  let count = 0;
+  for (const byte of buffer) {
+    if (byte === 10) count += 1;
+  }
+  return count;
+}
+
+function lineCountFromBreaks(bytes: number, lineBreaks: number, endsWithLineBreak: boolean): number {
+  return bytes === 0 ? 0 : lineBreaks + (endsWithLineBreak ? 0 : 1);
+}
+
+function sshStreamTruncationTrigger(
+  observedBytes: number,
+  observedLines: number,
+  maxBytes: number,
+  maxLines: number,
+): SshStdoutTruncationHint["trigger"] {
+  const bytes = observedBytes > maxBytes;
+  const lines = observedLines > maxLines;
+  if (bytes && lines) return "bytes-and-lines";
+  return bytes ? "bytes" : "lines";
+}
+
+function prefixLengthWithinLineBudget(
+  chunk: Buffer,
+  currentBytes: number,
+  currentLineBreaks: number,
+  currentEndsWithLineBreak: boolean,
+  maxLines: number,
+): number {
+  if (lineCountFromBreaks(currentBytes, currentLineBreaks, currentEndsWithLineBreak) >= maxLines) return 0;
+  let bytes = currentBytes;
+  let lineBreaks = currentLineBreaks;
+  let endsWithLineBreak = currentEndsWithLineBreak;
+  for (let index = 0; index < chunk.length; index += 1) {
+    const byte = chunk[index] ?? 0;
+    bytes += 1;
+    if (byte === 10) lineBreaks += 1;
+    endsWithLineBreak = byte === 10;
+    if (lineCountFromBreaks(bytes, lineBreaks, endsWithLineBreak) > maxLines) return index;
+  }
+  return chunk.length;
+}
+
 function brokerSource(): string {
   return String.raw`
 const open = JSON.parse(process.argv[2] || process.argv[1] || "{}");
@@ -3769,6 +3921,10 @@ export async function runSsh(config: UniDeskConfig, providerId: string, args: st
       invocation,
       transport: "backend-core-broker",
     });
+    const stderrForwarder = createSshStderrForwarder({
+      invocation,
+      transport: "backend-core-broker",
+    });
     child.stdout.on("data", (chunk: Buffer) => {
       const hint = stdoutForwarder.write(chunk);
       if (hint !== null) {
@@ -3776,11 +3932,21 @@ export async function runSsh(config: UniDeskConfig, providerId: string, args: st
         process.stderr.write(hint);
       }
     });
+    child.stderr.on("data", (chunk: Buffer) => {
+      appendStderrTail(chunk);
+      const hint = stderrForwarder.write(chunk);
+      if (hint !== null) {
+        appendStderrTail(hint);
+        process.stderr.write(hint);
+      }
+    });
+  }
+  if (parsed.remoteCommand === null) {
+    child.stderr.on("data", (chunk: Buffer) => {
+      appendStderrTail(chunk);
+      process.stderr.write(chunk);
+    });
   }
-  child.stderr.on("data", (chunk: Buffer) => {
-    appendStderrTail(chunk);
-    process.stderr.write(chunk);
-  });
 
   return await new Promise<number>((resolve) => {
     let settled = false;