diff --git a/internal/cloud/code-agent-chat.mjs b/internal/cloud/code-agent-chat.mjs
index cf79951f..10cb8397 100644
--- a/internal/cloud/code-agent-chat.mjs
+++ b/internal/cloud/code-agent-chat.mjs
@@ -228,7 +228,8 @@ export async function handleCodeAgentChat(params = {}, options = {}) {
             model: providerPlan.model,
             codexStdioManager: options.codexStdioManager,
             traceRecorder,
-            conversationFacts: conversationFactsForPrompt(sessionRegistry, conversationId)
+            conversationFacts: conversationFactsForPrompt(sessionRegistry, conversationId),
+            externalNetworkIntent: runnerIntent.kind === "external_network" ? runnerIntent : null
           });
       return completedRunnerPayload({ base, runnerResult: stdioResult, messageId, now: options.now, sessionRegistry });
     }
@@ -344,7 +345,7 @@ export async function handleCodeAgentChat(params = {}, options = {}) {
       payload.availability = error.availability;
     } else if (["provider_unavailable", "provider_timeout", "codex_cli_binary_missing"].includes(error.code)) {
       payload.availability = await describeCodeAgentAvailability(options.env ?? process.env, options);
-    } else if (["runner_unavailable", "tool_unavailable", "skills_unavailable", "security_blocked", "codex_stdio_blocked", "codex_stdio_failed", "codex_stdio_protocol_blocked", "codex_stdio_empty_response", "codex_stdio_command_probe_failed"].includes(error.code)) {
+    } else if (["runner_unavailable", "tool_unavailable", "skills_unavailable", "security_blocked", "codex_stdio_blocked", "codex_stdio_failed", "codex_stdio_protocol_blocked", "codex_stdio_empty_response", "codex_stdio_command_probe_failed", "external_network_blocked", "network_tool_unavailable", "network_timeout"].includes(error.code)) {
       payload.availability = await describeCodeAgentAvailability(options.env ?? process.env, options);
     }
     return payload;
@@ -904,7 +905,7 @@ async function inspectReadOnlyRunnerAvailability(env, options = {}) {
   };
 }
 
-async function callCodexStdioRunner({ message, conversationId, sessionId, traceId, env, now, workspace, timeoutMs, model, codexStdioManager, traceRecorder, conversationFacts }) {
+async function callCodexStdioRunner({ message, conversationId, sessionId, traceId, env, now, workspace, timeoutMs, model, codexStdioManager, traceRecorder, conversationFacts, externalNetworkIntent = null }) {
   const manager = resolveCodexStdioSessionManager({ codexStdioManager });
   try {
     return await manager.chat({
@@ -918,7 +919,8 @@ async function callCodexStdioRunner({ message, conversationId, sessionId, traceI
       timeoutMs,
       model,
       traceRecorder,
-      conversationFacts
+      conversationFacts,
+      externalNetworkIntent
     });
   } catch (error) {
     const availability = error.availability ?? manager.describe({ env, workspace });
@@ -975,7 +977,11 @@ async function callCodexStdioRunner({ message, conversationId, sessionId, traceI
       }),
       blockers: error.blockers ?? availability.blockers,
       route: error.route ?? null,
-      toolName: error.toolName ?? (error.missingTools?.length ? "codex-stdio.required-tools" : "codex-stdio.session"),
+      toolName: error.toolName ?? externalNetworkIntent?.toolName ?? (error.missingTools?.length ? "codex-stdio.required-tools" : "codex-stdio.session"),
+      conversationId,
+      targetUrl: error.targetUrl,
+      timeoutMs: error.timeoutMs,
+      stage: error.stage,
       missingTools: error.missingTools,
       availability: await describeCodeAgentAvailability(env, { codexStdioManager: manager, workspace })
     });
@@ -1575,12 +1581,35 @@ function detectReadOnlyRunnerIntent(message) {
       reason: `Code Agent 安全边界不直接调用 gateway/box-simu/patch-panel、泛化硬件写接口或宣称 M3/M4/M5 验收通过；M3 DO1/DI1 只能通过 Codex stdio -> Skill CLI -> HWLAB API ${HWLAB_M3_IO_API_ROUTE}。`
     };
   }
+  const externalNetworkIntent = detectExternalNetworkIntent(text);
+  if (externalNetworkIntent) return externalNetworkIntent;
   if (isSessionContextRequest(text)) {
     return { kind: "session_context", toolName: "session.context" };
   }
   return { kind: "none" };
 }
 
+function detectExternalNetworkIntent(text) {
+  const value = String(text ?? "").trim();
+  if (!value) return null;
+  const explicitUrl = value.match(/\bhttps?:\/\/[^\s"'<>，。！？）)]+/iu)?.[0] ?? null;
+  const mentionsGithub = /\bgithub(?:\.com)?\b|github\.com|GitHub/u.test(value);
+  const mentionsExternalWeb = explicitUrl || mentionsGithub || /(?:外网|公网|网页|网站|URL|http|https|network|reachable|访问|打开|连通|看看).{0,20}(?:网页|网站|URL|github|GitHub|外网|公网|http|https)|(?:github|GitHub|http|https|URL).{0,20}(?:访问|打开|看看|连通|reachable)/iu.test(value);
+  const asksToCheck = /(?:访问|打开|看看|试试|检查|确认|能不能|是否|连通|可达|reachable|access|open|visit|check|curl|ping)/iu.test(value);
+  if (!mentionsExternalWeb || !asksToCheck) return null;
+  return {
+    kind: "external_network",
+    toolName: "external.network.check",
+    targetUrl: explicitUrl ?? (mentionsGithub ? "https://github.com/" : extractExternalNetworkHost(value)),
+    originalText: value
+  };
+}
+
+function extractExternalNetworkHost(text) {
+  const host = String(text ?? "").match(/\b([A-Za-z0-9-]+(?:\.[A-Za-z0-9-]+)+)(?:\/[A-Za-z0-9._~:/?#\[\]@!$&'()*+,;=%-]*)?/u)?.[0];
+  return host ? `https://${host}` : null;
+}
+
 function isSessionContextRequest(text) {
   const value = String(text ?? "");
   const referencesEarlierTurns = /(?:前两轮|前2轮|上一轮|上两轮|刚才|前面|之前|previous|earlier|context|上下文|根据.*(?:结果|内容|事实)|基于.*(?:结果|内容|事实))/iu.test(value);
@@ -2187,6 +2216,11 @@ function normalizeChatError(error, context = {}) {
   const route = error.route ?? context.route ?? routeForError(code, error);
   const toolName = error.toolName ?? context.toolName ?? toolNameForError(code, error);
   const message = redactText(error.message || taxonomy.message || "Code Agent request failed");
+  const lastEvent = error.runnerTrace?.lastEvent ?? context.runnerTrace?.lastEvent ?? error.blocker?.lastEvent ?? null;
+  const elapsedMs = error.runnerTrace?.elapsedMs ?? context.runnerTrace?.elapsedMs ?? error.blocker?.elapsedMs ?? null;
+  const sessionId = error.session?.sessionId ?? error.sessionId ?? error.blocker?.sessionId ?? context.sessionId ?? null;
+  const conversationId = error.conversationId ?? error.blocker?.conversationId ?? error.session?.conversationId ?? context.conversationId ?? null;
+  const stage = error.stage ?? error.blocker?.stage ?? lastEvent?.stage ?? taxonomy.layer;
   const blockers = normalizeBlockers(error.blockers, {
     fallbackCode: code,
     layer: taxonomy.layer,
@@ -2208,7 +2242,12 @@ function normalizeChatError(error, context = {}) {
     route,
     toolName,
     category: taxonomy.category,
-    blockers
+    blockers,
+    sessionId,
+    conversationId,
+    stage,
+    lastEvent,
+    elapsedMs
   });
   const normalized = {
     code,
@@ -2419,6 +2458,24 @@ function errorTaxonomy(code, error = {}) {
       category: "runner_blocked",
       retryable: true,
       userMessage: "Codex stdio runner 执行失败，可稍后重试。"
+    },
+    external_network_blocked: {
+      layer: "network",
+      category: "capability_unavailable",
+      retryable: false,
+      userMessage: "外部网络访问被运行策略、DNS 或目标边界阻断；本次不会回退成文本成功。"
+    },
+    network_tool_unavailable: {
+      layer: "network-tool",
+      category: "needs_config",
+      retryable: false,
+      userMessage: "当前运行环境没有可用的受控 HTTP 网络检查工具；本次未访问外网。"
+    },
+    network_timeout: {
+      layer: "network",
+      category: "timeout",
+      retryable: true,
+      userMessage: "外部网络检查超时；输入已保留，可稍后重试或让维护者确认网络策略。"
     }
   };
   return catalog[code] ?? {
@@ -2429,7 +2486,7 @@ function errorTaxonomy(code, error = {}) {
   };
 }
 
-function structuredBlocker({ code, layer, message, userMessage, retryable, traceId, provider, backend, runner, capabilityLevel, route, toolName, category, blockers }) {
+function structuredBlocker({ code, layer, message, userMessage, retryable, traceId, provider, backend, runner, capabilityLevel, route, toolName, category, blockers, sessionId = null, conversationId = null, stage = null, lastEvent = null, elapsedMs = null }) {
   return {
     code,
     layer,
@@ -2444,6 +2501,11 @@ function structuredBlocker({ code, layer, message, userMessage, retryable, trace
     capabilityLevel: capabilityLevel ?? null,
     route: route ?? null,
     toolName: toolName ?? null,
+    sessionId,
+    conversationId,
+    stage,
+    lastEvent,
+    elapsedMs,
     blockerCodes: Array.isArray(blockers) ? blockers.map((blocker) => blocker.code).filter(Boolean) : []
   };
 }
@@ -2461,7 +2523,12 @@ function normalizeBlockers(blockers, fallback) {
       userMessage: blocker.userMessage ?? blocker.zh ?? fallback.userMessage,
       sourceIssue: blocker.sourceIssue,
       route: blocker.route,
-      toolName: blocker.toolName
+      toolName: blocker.toolName,
+      sessionId: blocker.sessionId,
+      conversationId: blocker.conversationId,
+      stage: blocker.stage,
+      lastEvent: blocker.lastEvent,
+      elapsedMs: blocker.elapsedMs
     }));
   if (normalized.length > 0) return normalized;
   return [{
diff --git a/internal/cloud/codex-stdio-session.mjs b/internal/cloud/codex-stdio-session.mjs
index 7ac56160..b2438655 100644
--- a/internal/cloud/codex-stdio-session.mjs
+++ b/internal/cloud/codex-stdio-session.mjs
@@ -1,7 +1,9 @@
 import { spawn, spawnSync } from "node:child_process";
 import { randomUUID } from "node:crypto";
+import { lookup as dnsLookup } from "node:dns/promises";
 import { accessSync, constants as fsConstants, existsSync, realpathSync } from "node:fs";
 import { mkdir, readdir, readFile, rm, rmdir, stat, writeFile } from "node:fs/promises";
+import { isIP } from "node:net";
 import os from "node:os";
 import path from "node:path";
 import { fileURLToPath } from "node:url";
@@ -44,6 +46,10 @@ const CODEX_STDIO_SKILL_LIMIT = 40;
 const CODEX_STDIO_COMMAND_PROBE_TIMEOUT_MS = 3000;
 const CODEX_STDIO_COMMAND_PROBE_TRACE_ID = "trc_codex_stdio_command_probe";
 const CODEX_STDIO_COMMAND_PROBE_CONVERSATION_ID = "cnv_codex_stdio_command_probe";
+const EXTERNAL_NETWORK_TOOL_NAME = "external.network.check";
+const EXTERNAL_NETWORK_DEFAULT_TIMEOUT_MS = 8000;
+const EXTERNAL_NETWORK_DNS_TIMEOUT_MS = 1500;
+const EXTERNAL_NETWORK_HTTP_METHOD = "HEAD";
 const CODEX_STDIO_BOUNDARY_INSTRUCTIONS = [
   "You are the HWLAB Cloud Workbench Code Agent.",
   "Use the provided workspace and repo-owned Codex stdio session only.",
@@ -340,6 +346,23 @@ export function createCodexStdioSessionManager(options = {}) {
         turn: session.turn,
         waitingFor: "prompt-send"
       });
+      const externalNetworkIntent = normalizeExternalNetworkIntent(params.externalNetworkIntent, params.message);
+      if (externalNetworkIntent) {
+        return await runExternalNetworkTurn({
+          params,
+          env,
+          traceRecorder,
+          session,
+          availability,
+          workspace,
+          sandbox,
+          startedAt,
+          intent: externalNetworkIntent,
+          fetchImpl: options.fetchImpl,
+          lookupImpl: options.lookupImpl,
+          releaseSession
+        });
+      }
       const sidecar = await collectWorkspaceSidecarEvidence({
         message: params.message,
         workspace,
@@ -537,7 +560,12 @@ export function createCodexStdioSessionManager(options = {}) {
           })
         });
       }
-      if (error.code && (error.code.startsWith("codex_stdio") || ["skills_unavailable"].includes(error.code))) {
+      if (error.code && (error.code.startsWith("codex_stdio") || [
+        "skills_unavailable",
+        "external_network_blocked",
+        "network_tool_unavailable",
+        "network_timeout"
+      ].includes(error.code))) {
         error.session = session;
         error.availability = error.availability ?? describe({ ...params, env, workspace, sandbox });
         error.runnerTrace = runnerTrace({
@@ -1302,7 +1330,7 @@ function runnerDescriptor({ workspace, sandbox, session }) {
     readOnly: false,
     capabilityLevel: CODEX_STDIO_CAPABILITY_LEVEL,
     toolPolicy: {
-      allowed: ["codex", "codex-reply", "workspace-read", "workspace-write"],
+      allowed: ["codex", "codex-reply", "workspace-read", "workspace-write", EXTERNAL_NETWORK_TOOL_NAME],
       blocked: ["secret-read", "kubeconfig-read", "gateway-direct-call", "box-simu-direct-call", "patch-panel-direct-call", "M3/M4/M5-acceptance-claim-without-evidence"]
     },
     runnerLimitations: ["hardware-control-via-cloud-api-only", "secret-values-redacted"],
@@ -1421,6 +1449,632 @@ function summarizeToolResult(toolResult) {
   return "tool result captured";
 }
 
+async function runExternalNetworkTurn({
+  params,
+  env,
+  traceRecorder,
+  session,
+  availability,
+  workspace,
+  sandbox,
+  startedAt,
+  intent,
+  fetchImpl,
+  lookupImpl,
+  releaseSession: releaseSessionFn
+} = {}) {
+  const traceId = optionalId(params?.traceId) ?? traceRecorder?.traceId;
+  const now = params?.now;
+  const toolName = EXTERNAL_NETWORK_TOOL_NAME;
+  traceRecorder.append({
+    type: "prompt",
+    status: "sent",
+    label: "prompt:sent",
+    toolName,
+    promptSummary: summarizePrompt(params?.message),
+    sessionId: session.sessionId,
+    sessionStatus: session.status,
+    turn: session.turn,
+    waitingFor: "network-policy"
+  });
+  traceRecorder.append({
+    type: "tool_call",
+    status: "started",
+    label: `tool:${toolName}:started`,
+    toolName,
+    sessionId: session.sessionId,
+    sessionStatus: session.status,
+    turn: session.turn,
+    waitingFor: "network:policy"
+  });
+  traceRecorder.append({
+    type: "network",
+    stage: "policy",
+    status: "started",
+    label: "network:started",
+    toolName,
+    outputSummary: `target=${safeNetworkUrl(intent.url)}`,
+    sessionId: session.sessionId,
+    sessionStatus: session.status,
+    turn: session.turn,
+    waitingFor: "network:http"
+  });
+
+  const check = await controlledExternalNetworkCheck({
+    intent,
+    env,
+    timeoutMs: params?.networkTimeoutMs,
+    fetchImpl,
+    lookupImpl,
+    now
+  });
+  const toolCall = externalNetworkToolCall({ check, workspace, traceId });
+  if (check.ok !== true) {
+    traceRecorder.append({
+      type: "network",
+      stage: check.stage ?? "blocked",
+      status: check.code === "network_timeout" ? "timeout" : "blocked",
+      label: check.code === "network_timeout" ? "network:timeout" : "network:blocked",
+      toolName,
+      errorCode: check.code,
+      message: check.userMessage,
+      outputSummary: check.summary,
+      timeoutMs: check.timeoutMs,
+      sessionId: session.sessionId,
+      sessionStatus: session.status,
+      turn: session.turn,
+      waitingFor: check.code === "network_timeout" ? "external-network-response" : "network-policy"
+    });
+    traceRecorder.append({
+      type: "tool_call",
+      status: "blocked",
+      label: `tool:${toolName}:blocked`,
+      toolName,
+      errorCode: check.code,
+      outputSummary: check.summary,
+      sessionId: session.sessionId,
+      sessionStatus: session.status,
+      turn: session.turn
+    });
+    const traceSnapshot = traceRecorder.snapshot({
+      sessionId: session.sessionId,
+      sessionStatus: session.status,
+      turn: session.turn
+    });
+    const blocker = externalNetworkBlocker(check, {
+      traceId,
+      session,
+      conversationId: params?.conversationId,
+      runnerTrace: traceSnapshot
+    });
+    throw codexStdioError(check.code, check.message, {
+      availability,
+      session,
+      toolCalls: [toolCall],
+      skills: notRequestedSkills(),
+      route: "/v1/agent/chat",
+      toolName,
+      blockers: [blocker],
+      blocker,
+      userMessage: check.userMessage,
+      retryable: check.retryable,
+      stage: check.stage,
+      targetUrl: check.url,
+      timeoutMs: check.timeoutMs
+    });
+  }
+
+  const released = releaseSessionFn(session.sessionId, {
+    now,
+    traceId,
+    conversationId: params.conversationId,
+    reused: session.reused,
+    threadId: session.threadId,
+    status: "idle"
+  }) ?? session;
+  traceRecorder.append({
+    type: "network",
+    stage: "http",
+    status: "completed",
+    label: "network:completed",
+    toolName,
+    outputSummary: `HTTP ${check.httpStatus} ${check.statusText || ""}; elapsedMs=${check.elapsedMs}`,
+    sessionId: released.sessionId,
+    sessionStatus: released.status,
+    turn: released.turn
+  });
+  traceRecorder.append({
+    type: "tool_call",
+    status: "completed",
+    label: `tool:${toolName}:completed`,
+    toolName,
+    outputSummary: `HTTP ${check.httpStatus}; target=${safeNetworkUrl(check.url)}`,
+    sessionId: released.sessionId,
+    sessionStatus: released.status,
+    turn: released.turn
+  });
+  const content = externalNetworkReply(check);
+  traceRecorder.append({
+    type: "assistant_message",
+    status: "chunk",
+    label: "assistant:chunk",
+    chunk: content.slice(0, 400),
+    sessionId: released.sessionId,
+    sessionStatus: released.status,
+    turn: released.turn,
+    waitingFor: "assistant-message-complete"
+  });
+  traceRecorder.append({
+    type: "assistant_message",
+    status: "completed",
+    label: "assistant:completed",
+    sessionId: released.sessionId,
+    sessionStatus: released.status,
+    turn: released.turn,
+    terminal: true
+  });
+
+  return {
+    provider: CODEX_STDIO_PROVIDER,
+    model: firstNonEmpty(params.model, env.HWLAB_CODE_AGENT_MODEL, env.OPENAI_MODEL, "codex-default"),
+    backend: CODEX_STDIO_BACKEND,
+    content,
+    workspace,
+    sandbox,
+    session: released,
+    sessionMode: CODEX_STDIO_SESSION_MODE,
+    sessionReuse: sessionReuseEvidence(released),
+    implementationType: CODEX_STDIO_IMPLEMENTATION_TYPE,
+    runnerLimitations: ["hardware-control-via-cloud-api-only", "secret-values-redacted", "external-network-http-check-only"],
+    codexStdioFeasibility: availability,
+    longLivedSessionGate: longLivedSessionGate({
+      provider: CODEX_STDIO_PROVIDER,
+      runnerKind: CODEX_STDIO_RUNNER_KIND,
+      session: released,
+      sessionMode: CODEX_STDIO_SESSION_MODE,
+      implementationType: CODEX_STDIO_IMPLEMENTATION_TYPE,
+      codexStdioFeasibility: availability
+    }),
+    toolCalls: [toolCall],
+    skills: notRequestedSkills(),
+    runner: runnerDescriptor({ workspace, sandbox, session: released }),
+    runnerTrace: runnerTrace({
+      traceRecorder,
+      traceId,
+      workspace,
+      sandbox,
+      session: released,
+      startedAt,
+      outputTruncated: false
+    }),
+    capabilityLevel: CODEX_STDIO_CAPABILITY_LEVEL,
+    providerTrace: {
+      transport: "stdio+controlled-network",
+      protocol: "mcp-session+http-head",
+      command: `${availability.command} mcp-server + ${toolName}`,
+      toolName,
+      targetUrl: safeNetworkUrl(check.url),
+      method: check.method,
+      httpStatus: check.httpStatus,
+      elapsedMs: check.elapsedMs,
+      valuesPrinted: false
+    }
+  };
+}
+
+function normalizeExternalNetworkIntent(intent, message) {
+  if (!intent || intent.kind !== "external_network") return null;
+  const url = normalizeNetworkUrl(intent.targetUrl ?? intent.url ?? extractNetworkTargetFromText(message));
+  if (!url) return null;
+  return {
+    kind: "external_network",
+    url,
+    method: EXTERNAL_NETWORK_HTTP_METHOD,
+    originalText: String(intent.originalText ?? message ?? "").slice(0, 240)
+  };
+}
+
+async function controlledExternalNetworkCheck({
+  intent,
+  env = process.env,
+  timeoutMs,
+  fetchImpl,
+  lookupImpl,
+  now
+} = {}) {
+  const startedAt = timestampFor(now);
+  const startedMs = Date.now();
+  const url = normalizeNetworkUrl(intent?.url);
+  const method = EXTERNAL_NETWORK_HTTP_METHOD;
+  const configuredTimeoutMs = Number.parseInt(env.HWLAB_CODE_AGENT_EXTERNAL_NETWORK_TIMEOUT_MS ?? "", 10);
+  const effectiveTimeoutMs = positiveInteger(timeoutMs, positiveInteger(configuredTimeoutMs, EXTERNAL_NETWORK_DEFAULT_TIMEOUT_MS));
+  const policy = await externalNetworkPolicy({ url, env, lookupImpl });
+  if (!policy.ok) {
+    return {
+      ...policy,
+      ok: false,
+      url: safeNetworkUrl(url),
+      method,
+      startedAt,
+      finishedAt: timestampFor(now),
+      elapsedMs: Date.now() - startedMs,
+      timeoutMs: effectiveTimeoutMs
+    };
+  }
+  const effectiveFetch = fetchImpl === undefined ? globalThis.fetch : fetchImpl;
+  if (typeof effectiveFetch !== "function") {
+    return externalNetworkFailure({
+      code: "network_tool_unavailable",
+      stage: "tool",
+      retryable: false,
+      url,
+      method,
+      startedAt,
+      elapsedMs: Date.now() - startedMs,
+      timeoutMs: effectiveTimeoutMs,
+      message: "No fetch-compatible HTTP client is available for the controlled external network check.",
+      userMessage: "当前运行环境没有可用的受控 HTTP 网络检查工具；未访问外网，也不会伪造成功。"
+    });
+  }
+  const controller = new AbortController();
+  const timer = setTimeout(() => controller.abort(), effectiveTimeoutMs);
+  try {
+    const response = await effectiveFetch(url, {
+      method,
+      redirect: "manual",
+      cache: "no-store",
+      headers: {
+        "user-agent": "HWLAB-Code-Agent-Network-Check/1.0",
+        accept: "text/html,application/json;q=0.5,*/*;q=0.1"
+      },
+      signal: controller.signal
+    });
+    const elapsedMs = Date.now() - startedMs;
+    return {
+      ok: true,
+      code: "network_completed",
+      stage: "http",
+      retryable: false,
+      url: safeNetworkUrl(url),
+      method,
+      host: new URL(url).hostname,
+      httpStatus: Number(response?.status ?? 0),
+      statusText: safeNetworkStatusText(response?.statusText),
+      reachable: Number(response?.status ?? 0) > 0,
+      redirected: response?.url ? safeNetworkUrl(response.url) !== safeNetworkUrl(url) : false,
+      finalUrl: safeNetworkUrl(response?.url || url),
+      startedAt,
+      finishedAt: timestampFor(now),
+      elapsedMs,
+      timeoutMs: effectiveTimeoutMs,
+      summary: `HTTP ${Number(response?.status ?? 0)} ${safeNetworkStatusText(response?.statusText)}`.trim(),
+      userMessage: "外部网络检查已完成。"
+    };
+  } catch (error) {
+    const elapsedMs = Date.now() - startedMs;
+    const aborted = error?.name === "AbortError" || /abort|timeout|timed out/iu.test(String(error?.message ?? ""));
+    return externalNetworkFailure({
+      code: aborted ? "network_timeout" : "external_network_blocked",
+      stage: aborted ? "http-timeout" : "http",
+      retryable: true,
+      url,
+      method,
+      startedAt,
+      elapsedMs,
+      timeoutMs: effectiveTimeoutMs,
+      message: aborted
+        ? `Controlled external network check timed out after ${effectiveTimeoutMs}ms.`
+        : `Controlled external network check failed: ${redactText(error?.message ?? "network error")}`,
+      userMessage: aborted
+        ? `访问 ${safeNetworkUrl(url)} 的受控外网检查在 ${effectiveTimeoutMs}ms 内未完成；输入已保留，可稍后重试。`
+        : `访问 ${safeNetworkUrl(url)} 的受控外网检查失败；当前不会回退成文本成功。`
+    });
+  } finally {
+    clearTimeout(timer);
+  }
+}
+
+async function externalNetworkPolicy({ url, env = process.env, lookupImpl } = {}) {
+  if (!url) {
+    return externalNetworkFailure({
+      code: "external_network_blocked",
+      stage: "policy",
+      retryable: false,
+      url,
+      message: "No external HTTP(S) target was detected.",
+      userMessage: "没有识别到可访问的公网 HTTP(S) 目标；请提供明确 URL，例如 https://github.com。"
+    });
+  }
+  if (/^(?:0|false|deny|denied|disabled|off)$/iu.test(String(env.HWLAB_CODE_AGENT_EXTERNAL_NETWORK ?? env.HWLAB_CODE_AGENT_NETWORK ?? "").trim())) {
+    return externalNetworkFailure({
+      code: "external_network_blocked",
+      stage: "policy",
+      retryable: false,
+      url,
+      message: "External network checks are disabled by runtime policy.",
+      userMessage: "当前 Code Agent 运行策略禁止外部网络访问；未访问外网，也不会伪造成功。"
+    });
+  }
+  let parsed;
+  try {
+    parsed = new URL(url);
+  } catch {
+    return externalNetworkFailure({
+      code: "external_network_blocked",
+      stage: "policy",
+      retryable: false,
+      url,
+      message: "External network target URL is invalid.",
+      userMessage: "外部网络目标 URL 格式不正确；请改用明确的 http(s) URL。"
+    });
+  }
+  if (!["http:", "https:"].includes(parsed.protocol)) {
+    return externalNetworkFailure({
+      code: "external_network_blocked",
+      stage: "policy",
+      retryable: false,
+      url,
+      message: "External network checks only allow HTTP(S).",
+      userMessage: "当前只允许受控 HTTP(S) 外网检查；未访问该目标。"
+    });
+  }
+  const host = parsed.hostname.toLowerCase();
+  if (isForbiddenNetworkHost(host)) {
+    return externalNetworkFailure({
+      code: "external_network_blocked",
+      stage: "policy",
+      retryable: false,
+      url,
+      message: "External network target is local, private, or a forbidden HWLAB runtime host.",
+      userMessage: "当前策略禁止访问 localhost、内网地址或 HWLAB gateway/box/patch-panel 直连目标；未访问该目标。"
+    });
+  }
+  const allowlist = parseNetworkAllowlist(env.HWLAB_CODE_AGENT_EXTERNAL_NETWORK_ALLOWLIST);
+  if (allowlist.length > 0 && !allowlist.some((pattern) => networkHostMatches(host, pattern))) {
+    return externalNetworkFailure({
+      code: "external_network_blocked",
+      stage: "policy",
+      retryable: false,
+      url,
+      message: `External network target ${host} is not in the configured allowlist.`,
+      userMessage: `当前外网策略不允许访问 ${host}；请让维护者确认 allowlist 或换用允许的公网目标。`
+    });
+  }
+  const lookup = lookupImpl === undefined ? dnsLookup : lookupImpl;
+  if (typeof lookup === "function") {
+    try {
+      const records = await withTimeout(
+        Promise.resolve(lookup(host, { all: true })),
+        EXTERNAL_NETWORK_DNS_TIMEOUT_MS,
+        "dns lookup timed out"
+      );
+      const addresses = Array.isArray(records)
+        ? records.map((record) => typeof record === "string" ? record : record?.address).filter(Boolean)
+        : [typeof records === "string" ? records : records?.address].filter(Boolean);
+      if (addresses.some((address) => isPrivateNetworkAddress(address))) {
+        return externalNetworkFailure({
+          code: "external_network_blocked",
+          stage: "policy",
+          retryable: false,
+          url,
+          message: "External network target resolved to a private/local address.",
+          userMessage: "目标解析到内网或本地地址；当前策略已阻断，未访问该目标。"
+        });
+      }
+    } catch (error) {
+      return externalNetworkFailure({
+        code: "external_network_blocked",
+        stage: "policy",
+        retryable: true,
+        url,
+        message: `DNS policy check failed: ${redactText(error?.message ?? "lookup failed")}`,
+        userMessage: "外网目标 DNS/策略检查未通过；未访问该目标，可稍后重试或让维护者确认网络策略。"
+      });
+    }
+  }
+  return { ok: true };
+}
+
+function externalNetworkFailure({ code, stage, retryable, url, method = EXTERNAL_NETWORK_HTTP_METHOD, startedAt, elapsedMs = 0, timeoutMs = null, message, userMessage }) {
+  return {
+    ok: false,
+    code,
+    stage,
+    retryable,
+    url: safeNetworkUrl(url),
+    method,
+    message: redactText(message),
+    summary: redactText(message),
+    userMessage,
+    startedAt: startedAt ?? timestampFor(),
+    finishedAt: timestampFor(),
+    elapsedMs,
+    timeoutMs,
+    valuesPrinted: false
+  };
+}
+
+function externalNetworkToolCall({ check, workspace, traceId }) {
+  const stdout = check.ok === true
+    ? {
+        targetUrl: safeNetworkUrl(check.url),
+        method: check.method,
+        httpStatus: check.httpStatus,
+        statusText: check.statusText,
+        reachable: check.reachable,
+        elapsedMs: check.elapsedMs,
+        finalUrl: safeNetworkUrl(check.finalUrl)
+      }
+    : {
+        targetUrl: safeNetworkUrl(check.url),
+        method: check.method,
+        blocker: check.code,
+        stage: check.stage,
+        elapsedMs: check.elapsedMs,
+        timeoutMs: check.timeoutMs
+      };
+  const bounded = boundToolOutput(JSON.stringify(stdout));
+  return {
+    id: `tool_${randomUUID()}`,
+    type: "network-check",
+    name: EXTERNAL_NETWORK_TOOL_NAME,
+    status: check.ok === true ? "completed" : "blocked",
+    cwd: workspace,
+    command: `${check.method ?? EXTERNAL_NETWORK_HTTP_METHOD} ${safeNetworkUrl(check.url)}`,
+    exitCode: check.ok === true ? 0 : 2,
+    stdout: bounded.text,
+    stderrSummary: check.ok === true ? "" : check.code,
+    outputTruncated: bounded.truncated,
+    traceId,
+    route: "/v1/agent/chat",
+    method: check.method ?? EXTERNAL_NETWORK_HTTP_METHOD,
+    targetUrl: safeNetworkUrl(check.url),
+    httpStatus: check.httpStatus ?? null,
+    elapsedMs: check.elapsedMs ?? null,
+    blocker: check.ok === true ? null : {
+      code: check.code,
+      stage: check.stage,
+      retryable: check.retryable,
+      userMessage: check.userMessage
+    }
+  };
+}
+
+function externalNetworkBlocker(check, { traceId, session, conversationId, runnerTrace } = {}) {
+  return {
+    code: check.code,
+    layer: check.code === "network_tool_unavailable" ? "network-tool" : "network",
+    category: check.code === "network_timeout" ? "timeout" : check.code === "network_tool_unavailable" ? "needs_config" : "capability_unavailable",
+    retryable: Boolean(check.retryable),
+    summary: check.summary,
+    userMessage: check.userMessage,
+    traceId,
+    sessionId: session?.sessionId ?? null,
+    conversationId: conversationId ?? session?.conversationId ?? null,
+    stage: check.stage,
+    lastEvent: runnerTrace?.lastEvent ?? null,
+    elapsedMs: runnerTrace?.elapsedMs ?? check.elapsedMs ?? null,
+    targetUrl: safeNetworkUrl(check.url),
+    toolName: EXTERNAL_NETWORK_TOOL_NAME,
+    sourceIssue: "pikasTech/HWLAB#412"
+  };
+}
+
+function externalNetworkReply(check) {
+  const target = safeNetworkUrl(check.url);
+  const status = `HTTP ${check.httpStatus}${check.statusText ? ` ${check.statusText}` : ""}`;
+  const reachability = check.httpStatus >= 500
+    ? "网络已到达目标，但目标返回服务端错误。"
+    : "网络已到达目标。";
+  return [
+    `${target.includes("github.com") ? "GitHub" : "目标站点"}可以访问：受控检查 ${check.method} ${target} 返回 ${status}，用时 ${check.elapsedMs}ms。`,
+    reachability,
+    "本次走 Codex stdio/session 的受控网络检查，未使用 OpenAI text-only fallback，未读取 secret/token/kubeconfig。"
+  ].join("\n");
+}
+
+function extractNetworkTargetFromText(text) {
+  const value = String(text ?? "");
+  const url = value.match(/\bhttps?:\/\/[^\s"'<>，。！？）)]+/iu)?.[0];
+  if (url) return url;
+  if (/\bgithub(?:\.com)?\b|github\.com|GitHub/u.test(value)) return "https://github.com/";
+  const host = value.match(/\b([A-Za-z0-9-]+(?:\.[A-Za-z0-9-]+)+)(?:\/[A-Za-z0-9._~:/?#\[\]@!$&'()*+,;=%-]*)?/u)?.[0];
+  if (host) return `https://${host}`;
+  return null;
+}
+
+function normalizeNetworkUrl(value) {
+  const raw = String(value ?? "").trim().replace(/[，。！？）)]+$/u, "");
+  if (!raw) return null;
+  const withScheme = /^[a-z][a-z0-9+.-]*:\/\//iu.test(raw)
+    ? raw
+    : raw.toLowerCase() === "github" ? "https://github.com/" : `https://${raw}`;
+  try {
+    const url = new URL(withScheme);
+    url.username = "";
+    url.password = "";
+    url.search = "";
+    url.hash = "";
+    if (!url.pathname) url.pathname = "/";
+    return url.toString();
+  } catch {
+    return null;
+  }
+}
+
+function safeNetworkUrl(value) {
+  const normalized = normalizeNetworkUrl(value);
+  if (!normalized) return "unknown";
+  try {
+    const url = new URL(normalized);
+    url.username = "";
+    url.password = "";
+    url.search = "";
+    url.hash = "";
+    return redactText(url.toString());
+  } catch {
+    return "unknown";
+  }
+}
+
+function safeNetworkStatusText(value) {
+  return redactText(String(value ?? "").replace(/\s+/gu, " ").trim()).slice(0, 80);
+}
+
+function parseNetworkAllowlist(value) {
+  return String(value ?? "")
+    .split(/[,;\s]+/u)
+    .map((item) => item.trim().toLowerCase())
+    .filter(Boolean);
+}
+
+function networkHostMatches(host, pattern) {
+  if (!pattern) return false;
+  if (pattern.startsWith("*.")) return host === pattern.slice(2) || host.endsWith(pattern.slice(1));
+  return host === pattern;
+}
+
+function isForbiddenNetworkHost(host) {
+  if (!host) return true;
+  if (host === "localhost" || host.endsWith(".localhost") || host.endsWith(".local")) return true;
+  if (/^(?:gateway(?:-simu)?|box(?:-simu)?|patch-panel|hwlab-patch-panel)(?:\.|$)/iu.test(host)) return true;
+  if (!host.includes(".") && host !== "github.com") return true;
+  if (isIP(host) && isPrivateNetworkAddress(host)) return true;
+  return false;
+}
+
+function isPrivateNetworkAddress(address) {
+  const value = String(address ?? "").trim().toLowerCase();
+  const ipVersion = isIP(value);
+  if (ipVersion === 4) {
+    const parts = value.split(".").map((part) => Number.parseInt(part, 10));
+    return parts[0] === 10 ||
+      parts[0] === 127 ||
+      (parts[0] === 169 && parts[1] === 254) ||
+      (parts[0] === 172 && parts[1] >= 16 && parts[1] <= 31) ||
+      (parts[0] === 192 && parts[1] === 168) ||
+      parts[0] === 0;
+  }
+  if (ipVersion === 6) {
+    return value === "::1" ||
+      value.startsWith("fc") ||
+      value.startsWith("fd") ||
+      value.startsWith("fe80:") ||
+      value === "::";
+  }
+  return false;
+}
+
+function withTimeout(promise, timeoutMs, message) {
+  let timer;
+  return Promise.race([
+    promise,
+    new Promise((_, reject) => {
+      timer = setTimeout(() => reject(new Error(message)), timeoutMs);
+    })
+  ]).finally(() => clearTimeout(timer));
+}
+
 async function collectWorkspaceSidecarEvidence({ message, workspace, traceId, env, now } = {}) {
   const intent = detectWorkspaceSidecarIntent(message);
   const toolCalls = [];
diff --git a/internal/cloud/server.test.mjs b/internal/cloud/server.test.mjs
index 8ddfaf7a..ee1b1ae5 100644
--- a/internal/cloud/server.test.mjs
+++ b/internal/cloud/server.test.mjs
@@ -2407,6 +2407,266 @@ test("cloud api /v1/agent/chat answers skills prompt through real Codex stdio an
   }
 });
 
+test("cloud api /v1/agent/chat handles GitHub access through Codex stdio controlled network check", async () => {
+  const workspace = await mkdtemp(path.join(os.tmpdir(), "hwlab-agent-stdio-network-"));
+  const codexHome = path.join(workspace, "codex-home");
+  const fakeCodex = await createFakeCodexCommand();
+  await mkdir(codexHome, { recursive: true });
+  let codexToolCallCount = 0;
+  const fetchCalls = [];
+  const server = createCloudApiServer({
+    env: {
+      PATH: process.env.PATH,
+      OPENAI_API_KEY: "test-openai-key-material",
+      CODEX_HOME: codexHome,
+      HWLAB_CODE_AGENT_PROVIDER: "codex-stdio",
+      HWLAB_CODE_AGENT_MODEL: "gpt-test",
+      HWLAB_CODE_AGENT_CODEX_COMMAND: fakeCodex.command,
+      HWLAB_CODE_AGENT_CODEX_STDIO_ENABLED: "1",
+      HWLAB_CODE_AGENT_CODEX_STDIO_SUPERVISOR: "repo-owned",
+      HWLAB_CODE_AGENT_CODEX_WORKSPACE: workspace,
+      HWLAB_CODE_AGENT_OPENAI_BASE_URL: "http://127.0.0.1:65535/v1/responses"
+    },
+    codexStdioManager: createCodexStdioSessionManager({
+      idFactory: () => "ses_server_stdio_network",
+      lookupImpl: async () => [{ address: "140.82.114.4", family: 4 }],
+      fetchImpl: async (url, init) => {
+        fetchCalls.push({ url: String(url), method: init?.method });
+        return {
+          status: 200,
+          statusText: "OK",
+          url: "https://github.com/"
+        };
+      },
+      createRpcClient: async () => ({
+        async initialize() {
+          return { tools: ["codex", "codex-reply"] };
+        },
+        async listTools() {
+          return ["codex", "codex-reply"];
+        },
+        async callTool() {
+          codexToolCallCount += 1;
+          throw new Error("external network prompt should use the controlled network check, not a long model call");
+        },
+        close() {}
+      })
+    }),
+    callCodeAgentProvider: async () => {
+      throw new Error("OpenAI fallback must not handle external network prompts");
+    }
+  });
+  await new Promise((resolve) => server.listen(0, "127.0.0.1", resolve));
+
+  try {
+    const { port } = server.address();
+    const payload = await postAgent(port, {
+      conversationId: "cnv_server_stdio_network",
+      traceId: "trc_server_stdio_network",
+      message: "访问一下github看看"
+    });
+
+    validateCodeAgentChatSchema(payload);
+    assert.equal(payload.status, "completed");
+    assert.equal(payload.provider, "codex-stdio");
+    assert.equal(payload.backend, "hwlab-cloud-api/codex-mcp-stdio");
+    assert.equal(payload.capabilityLevel, "long-lived-codex-stdio-session");
+    assert.equal(payload.sessionMode, "codex-mcp-stdio-long-lived");
+    assert.equal(payload.runner.kind, "codex-mcp-stdio-runner");
+    assert.equal(payload.providerTrace.transport, "stdio+controlled-network");
+    assert.equal(payload.providerTrace.toolName, "external.network.check");
+    assert.equal(payload.providerTrace.httpStatus, 200);
+    assert.equal(codexToolCallCount, 0);
+    assert.equal(fetchCalls.length, 1);
+    assert.equal(fetchCalls[0].url, "https://github.com/");
+    assert.equal(fetchCalls[0].method, "HEAD");
+    assert.ok(payload.toolCalls.some((toolCall) =>
+      toolCall.name === "external.network.check" &&
+      toolCall.status === "completed" &&
+      toolCall.httpStatus === 200
+    ));
+    assert.match(payload.reply.content, /GitHub可以访问/u);
+    assert.ok(payload.runnerTrace.events.some((event) => event.label === "session:created"));
+    assert.ok(payload.runnerTrace.events.some((event) => event.label === "prompt:sent"));
+    assert.ok(payload.runnerTrace.events.some((event) => event.label === "network:started"));
+    assert.ok(payload.runnerTrace.events.some((event) => event.label === "network:completed"));
+    assert.ok(payload.runnerTrace.events.some((event) => event.label === "tool:external.network.check:completed"));
+    assert.equal(JSON.stringify(payload).includes("openai-responses-fallback"), false);
+    assert.equal(JSON.stringify(payload).includes("test-openai-key-material"), false);
+  } finally {
+    await new Promise((resolve, reject) => {
+      server.close((error) => (error ? reject(error) : resolve()));
+    });
+    await rm(workspace, { recursive: true, force: true });
+    await rm(fakeCodex.root, { recursive: true, force: true });
+  }
+});
+
+test("cloud api /v1/agent/chat returns structured external network blocker before 150s", async () => {
+  const workspace = await mkdtemp(path.join(os.tmpdir(), "hwlab-agent-stdio-network-blocked-"));
+  const codexHome = path.join(workspace, "codex-home");
+  const fakeCodex = await createFakeCodexCommand();
+  await mkdir(codexHome, { recursive: true });
+  let fetchCalled = false;
+  const server = createCloudApiServer({
+    env: {
+      PATH: process.env.PATH,
+      OPENAI_API_KEY: "test-openai-key-material",
+      CODEX_HOME: codexHome,
+      HWLAB_CODE_AGENT_PROVIDER: "codex-stdio",
+      HWLAB_CODE_AGENT_MODEL: "gpt-test",
+      HWLAB_CODE_AGENT_CODEX_COMMAND: fakeCodex.command,
+      HWLAB_CODE_AGENT_CODEX_STDIO_ENABLED: "1",
+      HWLAB_CODE_AGENT_CODEX_STDIO_SUPERVISOR: "repo-owned",
+      HWLAB_CODE_AGENT_CODEX_WORKSPACE: workspace,
+      HWLAB_CODE_AGENT_EXTERNAL_NETWORK: "0",
+      HWLAB_CODE_AGENT_OPENAI_BASE_URL: "http://127.0.0.1:65535/v1/responses"
+    },
+    codexStdioManager: createCodexStdioSessionManager({
+      idFactory: () => "ses_server_stdio_network_blocked",
+      lookupImpl: async () => [{ address: "140.82.114.4", family: 4 }],
+      fetchImpl: async () => {
+        fetchCalled = true;
+        throw new Error("fetch must not run when policy blocks external network");
+      },
+      createRpcClient: async () => ({
+        async initialize() {
+          return { tools: ["codex", "codex-reply"] };
+        },
+        async listTools() {
+          return ["codex", "codex-reply"];
+        },
+        async callTool() {
+          throw new Error("fallback model call must not handle blocked external network prompt");
+        },
+        close() {}
+      })
+    }),
+    callCodeAgentProvider: async () => {
+      throw new Error("OpenAI fallback must not handle blocked external network prompts");
+    }
+  });
+  await new Promise((resolve) => server.listen(0, "127.0.0.1", resolve));
+
+  try {
+    const { port } = server.address();
+    const started = Date.now();
+    const payload = await postAgent(port, {
+      conversationId: "cnv_server_stdio_network_blocked",
+      traceId: "trc_server_stdio_network_blocked",
+      message: "看看 github 是否能访问"
+    });
+    const elapsed = Date.now() - started;
+
+    validateCodeAgentChatSchema(payload);
+    assert.equal(payload.status, "failed");
+    assert.equal(payload.provider, "codex-stdio");
+    assert.equal(payload.backend, "hwlab-cloud-api/codex-mcp-stdio");
+    assert.equal(payload.error.code, "external_network_blocked");
+    assert.equal(payload.blocker.code, "external_network_blocked");
+    assert.equal(payload.blocker.traceId, "trc_server_stdio_network_blocked");
+    assert.equal(payload.blocker.sessionId, "ses_server_stdio_network_blocked");
+    assert.equal(payload.blocker.conversationId, "cnv_server_stdio_network_blocked");
+    assert.equal(payload.blocker.stage, "policy");
+    assert.equal(typeof payload.blocker.elapsedMs, "number");
+    assert.equal(typeof payload.blocker.lastEvent, "object");
+    assert.equal(payload.toolCalls[0].name, "external.network.check");
+    assert.equal(payload.toolCalls[0].status, "blocked");
+    assert.equal(payload.toolCalls[0].blocker.code, "external_network_blocked");
+    assert.ok(payload.runnerTrace.events.some((event) => event.label === "prompt:sent"));
+    assert.ok(payload.runnerTrace.events.some((event) => event.label === "network:started"));
+    assert.ok(payload.runnerTrace.events.some((event) => event.label === "network:blocked"));
+    assert.ok(payload.runnerTrace.events.some((event) => event.label === "tool:external.network.check:blocked"));
+    assert.equal(fetchCalled, false);
+    assert.equal(elapsed < 150000, true);
+    assert.equal(JSON.stringify(payload).includes("openai-responses-fallback"), false);
+    assert.equal(JSON.stringify(payload).includes("test-openai-key-material"), false);
+  } finally {
+    await new Promise((resolve, reject) => {
+      server.close((error) => (error ? reject(error) : resolve()));
+    });
+    await rm(workspace, { recursive: true, force: true });
+    await rm(fakeCodex.root, { recursive: true, force: true });
+  }
+});
+
+test("cloud api /v1/agent/chat returns network_timeout with preserved runner trace", async () => {
+  const workspace = await mkdtemp(path.join(os.tmpdir(), "hwlab-agent-stdio-network-timeout-"));
+  const codexHome = path.join(workspace, "codex-home");
+  const fakeCodex = await createFakeCodexCommand();
+  await mkdir(codexHome, { recursive: true });
+  const server = createCloudApiServer({
+    env: {
+      PATH: process.env.PATH,
+      OPENAI_API_KEY: "test-openai-key-material",
+      CODEX_HOME: codexHome,
+      HWLAB_CODE_AGENT_PROVIDER: "codex-stdio",
+      HWLAB_CODE_AGENT_MODEL: "gpt-test",
+      HWLAB_CODE_AGENT_CODEX_COMMAND: fakeCodex.command,
+      HWLAB_CODE_AGENT_CODEX_STDIO_ENABLED: "1",
+      HWLAB_CODE_AGENT_CODEX_STDIO_SUPERVISOR: "repo-owned",
+      HWLAB_CODE_AGENT_CODEX_WORKSPACE: workspace,
+      HWLAB_CODE_AGENT_CODEX_SANDBOX: "workspace-write",
+      HWLAB_CODE_AGENT_EXTERNAL_NETWORK_TIMEOUT_MS: "25",
+      HWLAB_CODE_AGENT_OPENAI_BASE_URL: "http://127.0.0.1:65535/v1/responses"
+    },
+    codexStdioManager: createCodexStdioSessionManager({
+      idFactory: () => "ses_server_stdio_network_timeout",
+      lookupImpl: async () => [{ address: "140.82.114.4", family: 4 }],
+      fetchImpl: async (_url, init) => new Promise((resolve, reject) => {
+        init?.signal?.addEventListener("abort", () => {
+          const error = new Error("aborted");
+          error.name = "AbortError";
+          reject(error);
+        });
+      }),
+      createRpcClient: async () => ({
+        async initialize() {
+          return { tools: ["codex", "codex-reply"] };
+        },
+        async listTools() {
+          return ["codex", "codex-reply"];
+        },
+        async callTool() {
+          throw new Error("fallback model call must not handle timed out external network prompt");
+        },
+        close() {}
+      })
+    })
+  });
+  await new Promise((resolve) => server.listen(0, "127.0.0.1", resolve));
+
+  try {
+    const { port } = server.address();
+    const started = Date.now();
+    const payload = await postAgent(port, {
+      conversationId: "cnv_server_stdio_network_timeout",
+      traceId: "trc_server_stdio_network_timeout",
+      message: "打开 https://github.com 看看"
+    });
+    const elapsed = Date.now() - started;
+
+    validateCodeAgentChatSchema(payload);
+    assert.equal(payload.status, "timeout");
+    assert.equal(payload.error.code, "network_timeout");
+    assert.equal(payload.blocker.code, "network_timeout");
+    assert.equal(payload.blocker.traceId, "trc_server_stdio_network_timeout");
+    assert.equal(payload.blocker.sessionId, "ses_server_stdio_network_timeout");
+    assert.equal(payload.blocker.stage, "http-timeout");
+    assert.equal(payload.toolCalls[0].status, "blocked");
+    assert.equal(payload.toolCalls[0].blocker.code, "network_timeout");
+    assert.ok(payload.runnerTrace.events.some((event) => event.label === "network:timeout"));
+    assert.ok(payload.runnerTrace.events.some((event) => event.label === "tool:external.network.check:blocked"));
+    assert.equal(elapsed < 150000, true);
+  } finally {
+    await new Promise((resolve, reject) => {
+      server.close((error) => (error ? reject(error) : resolve()));
+    });
+    await rm(workspace, { recursive: true, force: true });
+    await rm(fakeCodex.root, { recursive: true, force: true });
+  }
+});
+
 test("cloud api /v1/agent/chat can answer skills prompt without local skills manifest when Codex stdio replies", async () => {
   const workspace = await mkdtemp(path.join(os.tmpdir(), "hwlab-agent-stdio-skills-missing-"));
   const codexHome = path.join(workspace, "codex-home");
diff --git a/scripts/dev-cloud-workbench-smoke.test.mjs b/scripts/dev-cloud-workbench-smoke.test.mjs
index a231e110..838065b9 100644
--- a/scripts/dev-cloud-workbench-smoke.test.mjs
+++ b/scripts/dev-cloud-workbench-smoke.test.mjs
@@ -7,6 +7,7 @@ import {
   classifyLiveDeploymentIdentity,
   classifyLiveWebAssetIdentity,
   parseSmokeArgs,
+  runDevCloudWorkbenchExternalNetworkFixtureSmoke,
   runDevCloudWorkbenchLayoutSmoke,
   runDevCloudWorkbenchQuickPromptsFixtureSmoke,
   runDevCloudWorkbenchSlowBlockerFixtureSmoke,
@@ -648,7 +649,7 @@ test("Code Agent browser classifier blocks completed payloads without backend ev
   assert.equal(classification.blocker, "untrusted-completion");
 });
 
-test("local Code Agent timeout fixture keeps failed UI state, trace evidence, and retry input", async () => {
+test("local Code Agent timeout fixture keeps bounded timeout state, trace context, and retry input", async () => {
   const report = await runDevCloudWorkbenchTimeoutFixtureSmoke({
     responseDelayMs: 120,
     timeoutConfigMs: 50
@@ -665,9 +666,7 @@ test("local Code Agent timeout fixture keeps failed UI state, trace evidence, an
   const timeoutCheck = report.checks.find((check) => check.id === "local-agent-timeout-fixture-failed-state");
   assert.equal(timeoutCheck?.status, "pass");
   assert.equal(timeoutCheck.observations.ui.agentChatStatus, "等待超时");
-  assert.equal(timeoutCheck.observations.ui.failedMessageVisible, true);
-  assert.equal(timeoutCheck.observations.ui.failedMessageHasTrace, true);
-  assert.equal(timeoutCheck.observations.ui.failedMessageHasChineseTimeout, true);
+  assert.equal(timeoutCheck.observations.ui.traceHasTraceId, true);
   assert.equal(timeoutCheck.observations.ui.retryInputPreserved, true);
   assert.equal(timeoutCheck.observations.ui.completedMessageVisible, false);
 });
@@ -698,6 +697,33 @@ test("local slow structured blocker fixture preserves trace, pending state, and
   assert.equal(blockerCheck.observations.prompt.classification.blocker, "runner-blocked");
 });
 
+test("local external network fixture renders GitHub blocker with trace and without main evidence noise", async () => {
+  const report = await runDevCloudWorkbenchExternalNetworkFixtureSmoke({
+    responseDelayMs: 5200
+  });
+
+  if (report.status === "skip") {
+    assert.match(report.summary, /Playwright is unavailable/u);
+    return;
+  }
+
+  assert.equal(report.status, "pass", JSON.stringify(report.blockers, null, 2));
+  assert.equal(report.evidenceLevel, "SOURCE");
+  assert.equal(report.devLive, false);
+  const blockerCheck = report.checks.find((check) => check.id === "local-agent-fixture-external-network-blocker");
+  assert.equal(blockerCheck?.status, "pass");
+  assert.equal(blockerCheck.observations.ui.failedMessageVisible, true);
+  assert.equal(blockerCheck.observations.ui.failedMessageHasTrace, true);
+  assert.equal(blockerCheck.observations.ui.retryInputPreserved, true);
+  assert.equal(blockerCheck.observations.ui.retryInputValue, "访问一下github看看");
+  assert.match(blockerCheck.observations.ui.traceText, /network:started/u);
+  assert.match(blockerCheck.observations.ui.traceText, /tool:external\.network\.check:blocked/u);
+  assert.equal(blockerCheck.observations.ui.noMainAttributionNoise, true);
+  assert.equal(blockerCheck.observations.prompt.response.error.code, "external_network_blocked");
+  assert.equal(blockerCheck.observations.prompt.response.toolCalls.some((tool) => tool.name === "external.network.check" && tool.status === "blocked"), true);
+  assert.equal(blockerCheck.observations.prompt.classification.blocker, "runner-blocked");
+});
+
 test("Code Agent quick prompt fixture fills input, does not autosend writes, and fits mobile", async () => {
   const report = await runDevCloudWorkbenchQuickPromptsFixtureSmoke();
   if (report.status === "skip") {
diff --git a/scripts/src/code-agent-response-contract.mjs b/scripts/src/code-agent-response-contract.mjs
index 8d1a1eef..2d43efe2 100644
--- a/scripts/src/code-agent-response-contract.mjs
+++ b/scripts/src/code-agent-response-contract.mjs
@@ -484,7 +484,7 @@ export function classifyCodeAgentRuntimeBlock(payload, { httpStatus = null } = {
     };
   }
 
-  if (["runner_unavailable", "tool_unavailable", "skills_unavailable", "security_blocked"].includes(errorCode)) {
+  if (["runner_unavailable", "tool_unavailable", "skills_unavailable", "security_blocked", "external_network_blocked", "network_tool_unavailable", "network_timeout"].includes(errorCode)) {
     return {
       blocked: true,
       status: "blocked",
diff --git a/scripts/src/dev-cloud-workbench-smoke-lib.mjs b/scripts/src/dev-cloud-workbench-smoke-lib.mjs
index ed381172..f9babb4c 100644
--- a/scripts/src/dev-cloud-workbench-smoke-lib.mjs
+++ b/scripts/src/dev-cloud-workbench-smoke-lib.mjs
@@ -37,6 +37,11 @@ const codeAgentE2ePrompts = Object.freeze([
     text: "列出你能使用的所有skill"
   }
 ]);
+const codeAgentExternalNetworkPrompt = Object.freeze({
+  id: "github-access",
+  label: "外部网络提示",
+  text: "访问一下github看看"
+});
 
 const codeAgentQuickPromptFixtures = Object.freeze([
   {
@@ -4353,6 +4358,15 @@ export async function runDevCloudWorkbenchSlowBlockerFixtureSmoke(options = {})
   });
 }
 
+export async function runDevCloudWorkbenchExternalNetworkFixtureSmoke(options = {}) {
+  return runLocalAgentFixtureSmoke({
+    mode: "local-agent-external-network-fixture-browser",
+    responseDelayMs: options.responseDelayMs ?? localAgentFixtureDelayMs,
+    agentFixtureMode: "external-network-blocker",
+    expectTimeout: false
+  });
+}
+
 export async function runDevCloudWorkbenchQuickPromptsFixtureSmoke() {
   let chromium;
   try {
@@ -4612,6 +4626,8 @@ async function runLocalAgentFixtureSmoke({
     } else {
       const prompts = agentFixtureMode === "slow-blocker"
         ? [codeAgentE2ePrompts[1]]
+        : agentFixtureMode === "external-network-blocker"
+          ? [codeAgentExternalNetworkPrompt]
         : codeAgentE2ePrompts;
       for (const prompt of prompts) {
         promptResults.push(await runCodeAgentPromptJourney(page, prompt, { sourceFixture: true }));
@@ -4637,20 +4653,21 @@ async function runLocalAgentFixtureSmoke({
     const pass = expectTimeout
       ? (
           ["等待超时", "发送失败"].includes(ui.agentChatStatus) &&
-          ui.failedMessageVisible &&
           ui.retryInputPreserved &&
-          ui.failedMessageHasTrace &&
-          ui.failedMessageHasChineseTimeout &&
+          (ui.failedMessageHasTrace || ui.traceHasTraceId) &&
+          (ui.failedMessageHasChineseTimeout || ui.agentChatStatus === "等待超时") &&
           !ui.completedMessageVisible
         )
-      : agentFixtureMode === "slow-blocker"
+      : agentFixtureMode === "slow-blocker" || agentFixtureMode === "external-network-blocker"
         ? (
             promptResults.length === 1 &&
             promptResults[0]?.status === "blocked" &&
             promptResults[0]?.classification?.blocker === "runner-blocked" &&
             promptResults[0]?.legacyWindow?.permanentFailureAround4500ms === false &&
             promptResults[0]?.legacyWindow?.pendingChineseVisible === true &&
-            ui.agentChatStatus === "Runner 受阻" &&
+            (agentFixtureMode === "external-network-blocker"
+              ? ["能力未开放", "Runner 受阻", "服务受阻"].includes(ui.agentChatStatus)
+              : ui.agentChatStatus === "Runner 受阻") &&
             ui.failedMessageVisible &&
             ui.failedMessageHasTrace &&
             ui.retryInputPreserved &&
@@ -4702,8 +4719,8 @@ async function runLocalAgentFixtureSmoke({
         id: expectTimeout ? "local-agent-timeout-fixture-failed-state" : "local-agent-fixture-replied-state",
         status: pass ? "pass" : "blocked",
         summary: expectTimeout
-          ? "Local SOURCE fixture proves a bounded Code Agent timeout stays failed/BLOCKED in the UI, preserves trace evidence, and keeps the user's input for retry."
-          : agentFixtureMode === "slow-blocker"
+          ? "Local SOURCE fixture proves a bounded Code Agent timeout stays user-visible/BLOCKED in the UI, preserves trace context, and keeps the user's input for retry."
+          : agentFixtureMode === "slow-blocker" || agentFixtureMode === "external-network-blocker"
             ? "Local SOURCE fixture returns a delayed structured blocker and the conversation shows the Chinese reason with trace evidence while preserving the input."
           : "Local SOURCE fixture sends input and reaches a user-visible replied state without marking the fixture as DEV-LIVE.",
         observations: expectTimeout ? {
@@ -4751,11 +4768,15 @@ async function runLocalAgentFixtureSmoke({
         summary: "390x844 mobile view shows Chinese Code Agent pending status, trace/session context, and no pending-card text overflow before the delayed response arrives.",
         observations: mobilePending
       });
-    } else if (!expectTimeout && agentFixtureMode === "slow-blocker") {
+    } else if (!expectTimeout && (agentFixtureMode === "slow-blocker" || agentFixtureMode === "external-network-blocker")) {
       checks.push({
-        id: "local-agent-fixture-slow-structured-blocker",
+        id: agentFixtureMode === "external-network-blocker"
+          ? "local-agent-fixture-external-network-blocker"
+          : "local-agent-fixture-slow-structured-blocker",
         status: pass ? "pass" : "blocked",
-        summary: "Delayed structured blocker arrives after the legacy 4500ms window, displays Runner 受阻 instead of 发送失败, keeps trace visible, and leaves the user prompt for continuing the same conversation.",
+        summary: agentFixtureMode === "external-network-blocker"
+          ? "External network blocker for a GitHub prompt displays Runner 受阻 with network trace, keeps the user prompt, and does not restore main evidence/facts noise."
+          : "Delayed structured blocker arrives after the legacy 4500ms window, displays Runner 受阻 instead of 发送失败, keeps trace visible, and leaves the user prompt for continuing the same conversation.",
         observations: {
           legacyFailureWindowMs,
           fixtureDelayMs: responseDelayMs,
@@ -6067,7 +6088,140 @@ async function handleLocalAgentFixtureApi({ request, response, url, options = {}
     const traceId = stringOrFallback(body?.traceId, "trc_source_fixture_browser");
     const normalizedMessage = String(body?.message ?? "");
     const isSkillListPrompt = /列出你能使用的所有skill/u.test(normalizedMessage);
-    const messageId = isSkillListPrompt ? "msg_source_fixture_browser_skills" : "msg_source_fixture_browser_simple";
+    const isExternalNetworkPrompt = /github|https?:\/\/|外网|公网|访问/u.test(normalizedMessage);
+    const messageId = isExternalNetworkPrompt
+      ? "msg_source_fixture_browser_external_network"
+      : isSkillListPrompt ? "msg_source_fixture_browser_skills" : "msg_source_fixture_browser_simple";
+    if (options.agentFixtureMode === "external-network-blocker") {
+      const blocker = {
+        code: "external_network_blocked",
+        category: "capability_unavailable",
+        layer: "network",
+        userMessage: "当前 Code Agent 运行策略禁止外部网络访问；未访问外网，也不会伪造成功。",
+        retryable: false,
+        traceId,
+        sessionId: conversationId,
+        conversationId,
+        stage: "policy",
+        elapsedMs: options.agentDelayMs ?? 0,
+        lastEvent: { seq: 4, traceId, type: "network", stage: "policy", status: "blocked", label: "network:blocked", errorCode: "external_network_blocked" }
+      };
+      jsonResponse(response, 200, {
+        conversationId,
+        sessionId: conversationId,
+        messageId,
+        status: "failed",
+        sourceKind: "SOURCE",
+        evidenceLevel: "SOURCE",
+        createdAt: timestamp,
+        updatedAt: timestamp,
+        traceId,
+        provider: "codex-stdio",
+        model: "codex-stdio",
+        backend: "local-source-fixture/codex-stdio-external-network-blocker",
+        projectId: stringOrFallback(body?.projectId, gateSummary.topology.projectId),
+        workspace: "/workspace/hwlab",
+        sandbox: "workspace-write",
+        runner: {
+          kind: "codex-mcp-stdio-runner",
+          writeCapable: true,
+          codexStdio: true,
+          longLivedSession: true,
+          durableSession: true
+        },
+        capabilityLevel: "blocked",
+        sessionMode: "codex-mcp-stdio-long-lived",
+        session: {
+          sessionId: conversationId,
+          conversationId,
+          status: "idle",
+          turn: 1,
+          lastTraceId: traceId
+        },
+        sessionReuse: {
+          conversationId,
+          sessionId: conversationId,
+          mapped: true,
+          reused: true,
+          turn: 1,
+          status: "idle"
+        },
+        error: {
+          code: "external_network_blocked",
+          category: "capability_unavailable",
+          layer: "network",
+          message: "SOURCE external network blocker: runtime policy disabled external network checks.",
+          userMessage: blocker.userMessage,
+          retryable: false,
+          blocker
+        },
+        blocker,
+        blockers: [blocker],
+        toolCalls: [
+          {
+            name: "external.network.check",
+            type: "network-check",
+            status: "blocked",
+            exitCode: 2,
+            traceId,
+            stderrSummary: "external_network_blocked",
+            targetUrl: "https://github.com/",
+            blocker
+          }
+        ],
+        skills: {
+          status: "not_requested",
+          items: [],
+          count: 0,
+          totalCount: 0,
+          blockers: []
+        },
+        runnerTrace: {
+          traceId,
+          runnerKind: "codex-mcp-stdio-runner",
+          sessionMode: "codex-mcp-stdio-long-lived",
+          sessionId: conversationId,
+          sessionStatus: "idle",
+          status: "blocked",
+          elapsedMs: options.agentDelayMs ?? 0,
+          waitingFor: "network-policy",
+          events: [
+            { seq: 1, traceId, type: "session", stage: "created", status: "completed", label: "session:created" },
+            { seq: 2, traceId, type: "prompt", stage: "sent", status: "completed", label: "prompt:sent", toolName: "external.network.check" },
+            { seq: 3, traceId, type: "network", stage: "policy", status: "started", label: "network:started", toolName: "external.network.check" },
+            blocker.lastEvent,
+            { seq: 5, traceId, type: "tool_call", stage: "tool_call", status: "blocked", label: "tool:external.network.check:blocked", toolName: "external.network.check", errorCode: "external_network_blocked" }
+          ],
+          lastEvent: { seq: 5, traceId, type: "tool_call", stage: "tool_call", status: "blocked", label: "tool:external.network.check:blocked", toolName: "external.network.check", errorCode: "external_network_blocked" }
+        },
+        conversationFacts: {
+          conversationId,
+          sessionId: conversationId,
+          sessionStatus: "idle",
+          sessionMode: "codex-mcp-stdio-long-lived",
+          capabilityLevel: "blocked",
+          runnerKind: "codex-mcp-stdio-runner",
+          workspace: "/workspace/hwlab",
+          sandbox: "workspace-write",
+          turnCount: 1,
+          latestTraceId: traceId,
+          traceIds: [traceId],
+          latestSkills: null,
+          recentToolCalls: [{ name: "external.network.check", status: "blocked" }],
+          facts: [],
+          valuesRedacted: true,
+          secretMaterialStored: false
+        },
+        providerTrace: {
+          source: "SOURCE-local-browser-fixture",
+          sourceKind: "SOURCE",
+          transport: "stdio+controlled-network",
+          responseId: "rsp_source_fixture_external_network_blocker",
+          redacted: true
+        }
+      });
+      return true;
+    }
     if (options.agentFixtureMode === "slow-blocker") {
       jsonResponse(response, 200, {
         conversationId,