diff --git a/internal/cloud/code-agent-chat.mjs b/internal/cloud/code-agent-chat.mjs
index b9b5426e..cc67bbf2 100644
--- a/internal/cloud/code-agent-chat.mjs
+++ b/internal/cloud/code-agent-chat.mjs
@@ -2582,25 +2582,25 @@ function m3IoApiBaseUrlMissingBlocker({ route = HWLAB_M3_IO_API_ROUTE } = {}) {
 
 function m3IoSkillReply(skillResult) {
   const lines = [
-    `M3 IO Skill CLI result: status=${skillResult.status}; accepted=${skillResult.accepted}; route=${skillResult.route}; traceId=${skillResult.traceId}; operationId=${skillResult.operationId ?? "null"}.`
+    `M3 IO Skill CLI result: 已通过 Code Agent -> Skill CLI -> HWLAB API ${skillResult.route} 处理请求；status=${skillResult.status}; accepted=${skillResult.accepted}; traceId=${skillResult.traceId}; operationId=${skillResult.operationId ?? "null"}。`
   ];
   if (skillResult.audit?.summary) {
-    lines.push(`Audit: ${skillResult.audit.summary}.`);
+    lines.push(`Audit: ${skillResult.audit.summary}（audit 摘要）。`);
   }
   if (skillResult.evidence?.summary) {
-    lines.push(`Evidence: ${skillResult.evidence.summary}.`);
+    lines.push(`Evidence: ${skillResult.evidence.summary}（evidence 摘要）。`);
   }
   if (skillResult.blocker) {
-    lines.push(`Blocker: ${skillResult.blocker.code}; ${skillResult.blocker.zh ?? skillResult.blocker.message}.`);
+    lines.push(`Blocker: ${skillResult.blocker.code}; ${skillResult.blocker.zh ?? skillResult.blocker.message}（blocker）。`);
   }
   if (skillResult.action === "do.write") {
-    lines.push(`DO1 requested value=${String(skillResult.command?.value)}; DI1 readback=${String(skillResult.result?.targetReadback?.value ?? "unknown")}.`);
+    lines.push(`DO1 写入请求：res_boxsimu_1:DO1=${String(skillResult.command?.value)}；DI1 readback：res_boxsimu_2:DI1=${String(skillResult.result?.targetReadback?.value ?? "unknown")}。`);
   } else if (skillResult.action === "di.read") {
-    lines.push(`DI1 value=${String(skillResult.result?.value ?? "unknown")}.`);
+    lines.push(`DI1 读取结果：res_boxsimu_2:DI1=${String(skillResult.result?.value ?? "unknown")}。`);
   } else if (skillResult.readonly === true || skillResult.route === HWLAB_M3_STATUS_API_ROUTE) {
-    lines.push(`M3 status readback DI1=${String(skillResult.readback?.value ?? "unknown")}; readiness=${skillResult.readiness?.status ?? "unknown"}.`);
+    lines.push(`M3 status readback：res_boxsimu_2:DI1=${String(skillResult.readback?.value ?? "unknown")}；readiness=${skillResult.readiness?.status ?? "unknown"}。`);
   }
-  lines.push(`Boundary: Code Agent -> Skill CLI -> HWLAB API ${skillResult.route}; no direct gateway/box/patch-panel call; no OpenAI fallback used. This is source/artifact control capability, not DEV-LIVE verification.`);
+  lines.push(`Boundary/边界：本次只走 Code Agent -> Skill CLI -> HWLAB API ${skillResult.route}；没有直连 gateway/box/patch-panel，也没有使用 OpenAI fallback 冒充 toolCall。这是受控操作结果，不是 M3 DEV-LIVE 验收结论。`);
   return boundToolOutput(lines.join("\n"), READONLY_TOOL_OUTPUT_LIMIT).text;
 }
 
diff --git a/internal/cloud/server.test.mjs b/internal/cloud/server.test.mjs
index d89a97ad..0d0fef4d 100644
--- a/internal/cloud/server.test.mjs
+++ b/internal/cloud/server.test.mjs
@@ -2360,7 +2360,7 @@ test("cloud api /v1/agent/chat routes M3 IO through Skill CLI to /v1/m3/io only"
       },
       body: JSON.stringify({
         conversationId: "cnv_server-test-m3-skill",
-        message: "请通过 M3 DO1 写入 false，并回读 DI1"
+        message: "通过 HWLAB API 把 res_boxsimu_1 的 DO1 写成 false，然后读取 res_boxsimu_2 的 DI1。"
       })
     });
     assert.equal(response.status, 200);
@@ -2381,6 +2381,9 @@ test("cloud api /v1/agent/chat routes M3 IO through Skill CLI to /v1/m3/io only"
     assert.equal(payload.providerTrace.fallbackUsed, false);
     assert.equal(payload.providerTrace.method, "POST");
     assert.equal(payload.providerTrace.readback.value, false);
+    assert.match(payload.reply.content, /HWLAB API \/v1\/m3\/io/u);
+    assert.match(payload.reply.content, /res_boxsimu_1:DO1=false/u);
+    assert.match(payload.reply.content, /res_boxsimu_2:DI1=false/u);
     assert.equal(payload.runner.safety.directGatewayCallsAllowed, false);
     assert.equal(payload.runner.safety.directBoxSimuCallsAllowed, false);
     assert.equal(payload.runner.safety.directPatchPanelCallsAllowed, false);
@@ -2478,6 +2481,9 @@ test("cloud api /v1/agent/chat routes Codex stdio M3 request through in-process
     assert.equal(payload.runnerTrace.route, "/v1/m3/io");
     assert.equal(payload.providerTrace.codexStdio, true);
     assert.equal(payload.providerTrace.fallbackUsed, false);
+    assert.match(payload.reply.content, /HWLAB API \/v1\/m3\/io/u);
+    assert.match(payload.reply.content, /res_boxsimu_1:DO1=true/u);
+    assert.match(payload.reply.content, /res_boxsimu_2:DI1=true/u);
     assert.ok(payload.runner.toolPolicy.allowed.includes("POST /v1/m3/io"));
     assert.deepEqual(gatewayCalls.map((call) => new URL(call.url).pathname), [
       "/status",
diff --git a/scripts/code-agent-chat-smoke.mjs b/scripts/code-agent-chat-smoke.mjs
index 6c869051..dd67cd91 100644
--- a/scripts/code-agent-chat-smoke.mjs
+++ b/scripts/code-agent-chat-smoke.mjs
@@ -510,7 +510,7 @@ async function runLocalContractSmoke() {
     {
       conversationId: "cnv_code-agent-chat-m3-skill",
       traceId: "trc_code-agent-chat-m3-skill",
-      message: "请通过 M3 DO1 写入 true，并回读 DI1"
+      message: "通过 HWLAB API 把 res_boxsimu_1 的 DO1 写成 true，然后读取 res_boxsimu_2 的 DI1。"
     },
     {
       now: () => "2026-05-22T00:04:55.000Z",
@@ -583,13 +583,99 @@ async function runLocalContractSmoke() {
   assert.equal(m3SkillWrite.providerTrace.method, "POST");
   assert.equal(m3SkillWrite.providerTrace.readback.value, true);
   assert.equal(m3SkillWrite.runner.safety.directGatewayCallsAllowed, false);
+  assert.match(m3SkillWrite.reply.content, /HWLAB API \/v1\/m3\/io/u);
+  assert.match(m3SkillWrite.reply.content, /res_boxsimu_1:DO1=true/u);
+  assert.match(m3SkillWrite.reply.content, /res_boxsimu_2:DI1=true/u);
   assert.equal(m3SkillCalls.length, 1);
   assert.equal(m3SkillCalls[0].url, "http://hwlab-cloud-api.hwlab-dev.svc.cluster.local:6667/v1/m3/io");
+  assert.equal(m3SkillCalls[0].request.body.action, "do.write");
+  assert.equal(m3SkillCalls[0].request.body.value, true);
   assert.equal(m3SkillCalls[0].url.includes("gateway-simu"), false);
   assert.equal(m3SkillCalls[0].url.includes("box-simu"), false);
   assert.equal(m3SkillCalls[0].url.includes("patch-panel"), false);
   logOk("M3 Skill CLI routes through HWLAB API only");
 
+  const m3SkillFalseCalls = [];
+  const m3SkillWriteFalse = await handleCodeAgentChat(
+    {
+      conversationId: "cnv_code-agent-chat-m3-skill-false",
+      traceId: "trc_code-agent-chat-m3-skill-false",
+      message: "通过 HWLAB API 把 res_boxsimu_1 的 DO1 写成 false，然后读取 res_boxsimu_2 的 DI1。"
+    },
+    {
+      now: () => "2026-05-22T00:04:56.000Z",
+      env: {
+        PATH: process.env.PATH,
+        HWLAB_CODE_AGENT_WORKSPACE: process.cwd(),
+        HWLAB_CODE_AGENT_HWLAB_API_BASE_URL: "http://hwlab-cloud-api.hwlab-dev.svc.cluster.local:6667",
+        OPENAI_API_KEY: "must-not-be-used"
+      },
+      callProvider: async () => {
+        throw new Error("OpenAI fallback must not be used for M3 IO");
+      },
+      m3IoSkillRequestJson: async (url, request) => {
+        m3SkillFalseCalls.push({ url, request });
+        return {
+          ok: true,
+          status: 200,
+          body: {
+            status: "succeeded",
+            accepted: true,
+            action: "do.write",
+            traceId: "trc_code-agent-chat-m3-skill-false",
+            operationId: "op_m3_do_write_false_smoke",
+            auditId: "aud_m3_do_write_false_smoke_succeeded",
+            evidenceId: "evd_m3_do_write_false_smoke_succeeded",
+            auditState: {
+              status: "written_non_durable"
+            },
+            evidenceState: {
+              status: "blocked",
+              sourceKind: "BLOCKED",
+              blocker: "runtime_durable_not_green",
+              writeStatus: "written_non_durable"
+            },
+            durableStatus: {
+              status: "degraded",
+              durable: false,
+              blocker: "runtime_durable_not_green"
+            },
+            result: {
+              value: false,
+              targetReadback: {
+                status: "succeeded",
+                value: false
+              }
+            },
+            controlPath: {
+              cloudApi: true,
+              gatewaySimu: true,
+              boxSimu: true,
+              patchPanel: true,
+              frontendBypass: false
+            }
+          }
+        };
+      }
+    }
+  );
+  validateCodeAgentChatSchema(m3SkillWriteFalse);
+  assert.equal(m3SkillWriteFalse.status, "completed");
+  assert.equal(m3SkillWriteFalse.provider, "hwlab-skill-cli");
+  assert.equal(m3SkillWriteFalse.toolCalls[0].route, "/v1/m3/io");
+  assert.equal(m3SkillWriteFalse.toolCalls[0].method, "POST");
+  assert.equal(m3SkillWriteFalse.toolCalls[0].operationId, "op_m3_do_write_false_smoke");
+  assert.equal(m3SkillWriteFalse.toolCalls[0].readback.value, false);
+  assert.equal(m3SkillWriteFalse.providerTrace.fallbackUsed, false);
+  assert.match(m3SkillWriteFalse.reply.content, /HWLAB API \/v1\/m3\/io/u);
+  assert.match(m3SkillWriteFalse.reply.content, /res_boxsimu_1:DO1=false/u);
+  assert.match(m3SkillWriteFalse.reply.content, /res_boxsimu_2:DI1=false/u);
+  assert.equal(m3SkillFalseCalls.length, 1);
+  assert.equal(m3SkillFalseCalls[0].url, "http://hwlab-cloud-api.hwlab-dev.svc.cluster.local:6667/v1/m3/io");
+  assert.equal(m3SkillFalseCalls[0].request.body.action, "do.write");
+  assert.equal(m3SkillFalseCalls[0].request.body.value, false);
+  logOk("M3 Skill CLI handles user-direct false request through HWLAB API only");
+
   const directToolCallPayload = JSON.parse(JSON.stringify(m3SkillWrite));
   directToolCallPayload.toolCalls[0].hwlabApi = {
     route: "/v1/m3/io",