diff --git a/docs/m3-hardware-loop.md b/docs/m3-hardware-loop.md
index c0c608ab..a1ddab9b 100644
--- a/docs/m3-hardware-loop.md
+++ b/docs/m3-hardware-loop.md
@@ -43,3 +43,34 @@ patch-panel state application, real or simulator box observation, persisted
 audit events, and evidence records. That future work must preserve the same
 wiring contract and must keep routing decisions under `hwlab-patch-panel`
 ownership instead of mutating another box directly.
+
+## DEV Runtime Smoke
+
+Use this command only for the DEV simulator runtime:
+
+```sh
+node scripts/dev-m3-hardware-loop-smoke.mjs --live --confirm-dev --confirmed-non-production
+```
+
+The smoke writes `reports/dev-gate/dev-m3-hardware-loop.json`. It first checks
+the frozen DEV endpoint, `http://74.48.78.17:6667`, and stops at the first
+critical blocker from `docs/dev-acceptance-matrix.md`. When DEV ingress is not
+observable, the report is `blocked` and the script does not run the live
+`do.write true -> di.read true` operation.
+
+If DEV ingress is reachable, the script requires explicit direct DEV simulator
+targets through these environment variables:
+
+```text
+HWLAB_DEV_BOX_SIMU_1_URL
+HWLAB_DEV_BOX_SIMU_2_URL
+HWLAB_DEV_GATEWAY_SIMU_1_URL
+HWLAB_DEV_GATEWAY_SIMU_2_URL
+HWLAB_DEV_PATCH_PANEL_URL
+```
+
+Those targets must be HWLAB DEV simulator services, not UniDesk substitutes.
+The script then checks two box simulators, two gateway simulators, active
+patch-panel wiring for `box-simu-1 DO1 -> box-simu-2 DI1`, a live direct call
+that reads `DI1=true`, and returned audit/evidence identifiers. Fixture-backed
+local M3 output is never accepted as live DEV evidence.
diff --git a/reports/dev-gate/dev-m3-hardware-loop.json b/reports/dev-gate/dev-m3-hardware-loop.json
new file mode 100644
index 00000000..b567d4d9
--- /dev/null
+++ b/reports/dev-gate/dev-m3-hardware-loop.json
@@ -0,0 +1,159 @@
+{
+  "$schema": "https://hwlab.pikastech.local/schemas/dev-m3-hardware-loop-report.schema.json",
+  "$id": "https://hwlab.pikastech.local/reports/dev-gate/dev-m3-hardware-loop.json",
+  "reportVersion": "v1",
+  "issue": "pikasTech/HWLAB#38",
+  "taskId": "dev-m3-hardware-loop",
+  "commitId": "1e8d009e9531",
+  "acceptanceLevel": "dev_m3_hardware_loop",
+  "devOnly": true,
+  "prodDisabled": true,
+  "sourceContract": {
+    "status": "pass",
+    "documents": [
+      "docs/dev-acceptance-matrix.md",
+      "docs/m3-hardware-loop.md",
+      "fixtures/mvp/m3-hardware-loop/topology.json"
+    ],
+    "summary": "Source contracts define DEV-only M3 simulator wiring and prohibit fixture output as live evidence."
+  },
+  "validationCommands": [
+    "node --check scripts/dev-m3-hardware-loop-smoke.mjs",
+    "node scripts/dev-m3-hardware-loop-smoke.mjs --live --confirm-dev --confirmed-non-production",
+    "node --check scripts/validate-dev-gate-report.mjs",
+    "node scripts/validate-dev-gate-report.mjs"
+  ],
+  "runtimeTarget": {
+    "endpoint": "http://74.48.78.17:6667",
+    "namespace": "hwlab-dev",
+    "environment": "dev",
+    "requiredBoxSimulators": 2,
+    "requiredGatewaySimulators": 2,
+    "realHardwareAllowed": false,
+    "prodAllowed": false
+  },
+  "safetyGates": {
+    "liveFlagRequired": true,
+    "confirmDevRequired": true,
+    "confirmedNonProductionRequired": true,
+    "prodForbidden": true,
+    "realHardwareForbidden": true,
+    "secretReadForbidden": true,
+    "forcePushForbidden": true,
+    "unideskRuntimeSubstitutionForbidden": true
+  },
+  "liveChecks": [
+    {
+      "id": "static-contract-parse",
+      "status": "pass",
+      "summary": "DEV M3 smoke contract files were readable before live probing.",
+      "evidence": [
+        "docs/dev-acceptance-matrix.md",
+        "docs/m3-hardware-loop.md"
+      ]
+    },
+    {
+      "id": "endpoint-freeze",
+      "status": "pass",
+      "summary": "DEV endpoint is frozen at http://74.48.78.17:6667.",
+      "evidence": [
+        "http://74.48.78.17:6667"
+      ]
+    },
+    {
+      "id": "dev-ingress-health",
+      "status": "blocked",
+      "blockerClass": "network_blocker",
+      "summary": "DEV ingress at http://74.48.78.17:6667 did not return reachable HWLAB DEV health.",
+      "evidence": [
+        "{\"url\":\"http://74.48.78.17:6667/health/live\",\"method\":\"GET\",\"startedAt\":\"2026-05-21T16:38:29.319Z\",\"observedAt\":\"2026-05-21T16:38:33.884Z\",\"reached\":false,\"ok\":false,\"error\":{\"name\":\"Error\",\"message\":\"connect ECONNREFUSED 74.48.78.17:6667\",\"code\":\"ECONNREFUSED\"}}",
+        "{\"url\":\"http://74.48.78.17:6667/health\",\"method\":\"GET\",\"startedAt\":\"2026-05-21T16:38:33.885Z\",\"observedAt\":\"2026-05-21T16:38:36.674Z\",\"reached\":false,\"ok\":false,\"error\":{\"name\":\"Error\",\"message\":\"connect ECONNREFUSED 74.48.78.17:6667\",\"code\":\"ECONNREFUSED\"}}",
+        "{\"url\":\"http://74.48.78.17:6667/live\",\"method\":\"GET\",\"startedAt\":\"2026-05-21T16:38:36.674Z\",\"observedAt\":\"2026-05-21T16:38:39.674Z\",\"reached\":false,\"ok\":false,\"error\":{\"name\":\"Error\",\"message\":\"connect ECONNREFUSED 74.48.78.17:6667\",\"code\":\"ECONNREFUSED\"}}",
+        "{\"url\":\"http://74.48.78.17:6667/v1\",\"method\":\"GET\",\"startedAt\":\"2026-05-21T16:38:39.674Z\",\"observedAt\":\"2026-05-21T16:38:39.835Z\",\"reached\":false,\"ok\":false,\"error\":{\"name\":\"Error\",\"message\":\"connect ECONNREFUSED 74.48.78.17:6667\",\"code\":\"ECONNREFUSED\"}}"
+      ]
+    },
+    {
+      "id": "two-box-simu-online",
+      "status": "not_run",
+      "summary": "Stopped at DEV ingress per the DEV smoke matrix.",
+      "evidence": [
+        "No live DEV evidence collected for this check."
+      ]
+    },
+    {
+      "id": "two-gateway-simu-online",
+      "status": "not_run",
+      "summary": "Stopped at DEV ingress per the DEV smoke matrix.",
+      "evidence": [
+        "No live DEV evidence collected for this check."
+      ]
+    },
+    {
+      "id": "patch-panel-healthy",
+      "status": "not_run",
+      "summary": "Stopped at DEV ingress per the DEV smoke matrix.",
+      "evidence": [
+        "No live DEV evidence collected for this check."
+      ]
+    },
+    {
+      "id": "wiring-do1-di1-applied",
+      "status": "not_run",
+      "summary": "Stopped at DEV ingress per the DEV smoke matrix.",
+      "evidence": [
+        "No live DEV evidence collected for this check."
+      ]
+    },
+    {
+      "id": "direct-call-do-write-di-read",
+      "status": "not_run",
+      "summary": "Stopped at DEV ingress per the DEV smoke matrix.",
+      "evidence": [
+        "No live DEV evidence collected for this check."
+      ]
+    },
+    {
+      "id": "audit-evidence-traceable",
+      "status": "not_run",
+      "summary": "Stopped at DEV ingress per the DEV smoke matrix.",
+      "evidence": [
+        "No live DEV evidence collected for this check."
+      ]
+    }
+  ],
+  "localRuntimeObservations": [
+    {
+      "id": "docker-hwlab-containers",
+      "status": "not_observed",
+      "command": "docker ps --format {{.Names}}\t{{.Image}}\t{{.Status}}\t{{.Ports}}",
+      "summary": "No running docker container name/image/port line contained hwlab-."
+    },
+    {
+      "id": "kubectl-hwlab-dev",
+      "status": "unavailable",
+      "command": "command -v kubectl",
+      "summary": "kubectl is not available in this runner, so hwlab-dev namespace state was not observed."
+    }
+  ],
+  "liveOperation": {
+    "status": "not_run",
+    "operationId": "not_observed",
+    "traceId": "not_observed",
+    "auditId": "not_observed",
+    "evidenceId": "not_observed",
+    "summary": "No live do.write -> di.read operation was attempted because DEV ingress is blocked."
+  },
+  "blockers": [
+    {
+      "type": "network_blocker",
+      "scope": "dev-ingress-health",
+      "status": "open",
+      "summary": "Blocked at the #33 DEV runtime readiness condition: public DEV ingress does not accept HWLAB health requests, so #36/M3 hardware-loop checks were not reached."
+    }
+  ],
+  "summary": {
+    "status": "blocked",
+    "observedAt": "2026-05-21T16:38:29.315Z",
+    "result": "No live DEV M3 evidence was produced; fixture-backed local evidence was not used as a substitute."
+  }
+}
diff --git a/scripts/dev-m3-hardware-loop-smoke.mjs b/scripts/dev-m3-hardware-loop-smoke.mjs
new file mode 100644
index 00000000..649263a4
--- /dev/null
+++ b/scripts/dev-m3-hardware-loop-smoke.mjs
@@ -0,0 +1,737 @@
+#!/usr/bin/env node
+import assert from "node:assert/strict";
+import { execFileSync } from "node:child_process";
+import { randomUUID } from "node:crypto";
+import { access, mkdir, writeFile } from "node:fs/promises";
+import { request as httpRequest } from "node:http";
+import { request as httpsRequest } from "node:https";
+import path from "node:path";
+import { fileURLToPath } from "node:url";
+
+import { DEV_ENDPOINT, ENVIRONMENT_DEV } from "../internal/protocol/index.mjs";
+
+const repoRoot = path.resolve(path.dirname(fileURLToPath(import.meta.url)), "..");
+const defaultReportPath = "reports/dev-gate/dev-m3-hardware-loop.json";
+const namespace = "hwlab-dev";
+const issue = "pikasTech/HWLAB#38";
+
+const serviceTargets = Object.freeze([
+  {
+    id: "box-simu-1",
+    serviceId: "hwlab-box-simu",
+    urlEnv: "HWLAB_DEV_BOX_SIMU_1_URL",
+    statusPath: "/status"
+  },
+  {
+    id: "box-simu-2",
+    serviceId: "hwlab-box-simu",
+    urlEnv: "HWLAB_DEV_BOX_SIMU_2_URL",
+    statusPath: "/status"
+  },
+  {
+    id: "gateway-simu-1",
+    serviceId: "hwlab-gateway-simu",
+    urlEnv: "HWLAB_DEV_GATEWAY_SIMU_1_URL",
+    statusPath: "/status"
+  },
+  {
+    id: "gateway-simu-2",
+    serviceId: "hwlab-gateway-simu",
+    urlEnv: "HWLAB_DEV_GATEWAY_SIMU_2_URL",
+    statusPath: "/status"
+  },
+  {
+    id: "patch-panel",
+    serviceId: "hwlab-patch-panel",
+    urlEnv: "HWLAB_DEV_PATCH_PANEL_URL",
+    statusPath: "/status",
+    wiringPath: "/wiring",
+    routePath: "/signals/route"
+  }
+]);
+
+function parseArgs(argv) {
+  const flags = new Set();
+  const values = new Map();
+
+  for (let index = 0; index < argv.length; index += 1) {
+    const arg = argv[index];
+    if (!arg.startsWith("--")) {
+      throw new Error(`unexpected positional argument ${arg}`);
+    }
+    if (arg === "--output") {
+      const value = argv[index + 1];
+      assert.ok(value && !value.startsWith("--"), "--output requires a path");
+      values.set("output", value);
+      index += 1;
+      continue;
+    }
+    flags.add(arg);
+  }
+
+  return { flags, values };
+}
+
+function requireSafetyGates(flags) {
+  const forbiddenFlags = [
+    "--prod",
+    "--real-hardware",
+    "--read-secret",
+    "--read-token",
+    "--force-push",
+    "--restart-runtime",
+    "--restart-unidesk",
+    "--restart-code-queue",
+    "--restart-backend-core"
+  ];
+
+  for (const flag of forbiddenFlags) {
+    assert.ok(!flags.has(flag), `${flag} is forbidden for DEV M3 smoke`);
+  }
+
+  const live = flags.has("--live") || flags.has("--allow-live");
+  assert.ok(live, "DEV M3 smoke requires --live or --allow-live");
+  assert.ok(flags.has("--confirm-dev"), "live DEV smoke requires --confirm-dev");
+  assert.ok(
+    flags.has("--confirmed-non-production"),
+    "live DEV smoke requires --confirmed-non-production"
+  );
+}
+
+function isoNow() {
+  return new Date().toISOString();
+}
+
+function relativePath(absolutePath) {
+  return path.relative(repoRoot, absolutePath).replaceAll(path.sep, "/");
+}
+
+function resolveReportPath(value) {
+  const candidate = path.resolve(repoRoot, value ?? defaultReportPath);
+  assert.ok(candidate.startsWith(`${repoRoot}${path.sep}`), "report path must stay inside repository");
+  return candidate;
+}
+
+function currentCommit() {
+  try {
+    return execFileSync("git", ["rev-parse", "--short=12", "HEAD"], {
+      cwd: repoRoot,
+      encoding: "utf8",
+      stdio: ["ignore", "pipe", "pipe"]
+    }).trim();
+  } catch {
+    return "unknown";
+  }
+}
+
+function oneLine(value) {
+  return String(value).replace(/\s+/g, " ").trim();
+}
+
+function commandResult(command, args, { timeoutMs = 5000, maxChars = 3000 } = {}) {
+  try {
+    const stdout = execFileSync(command, args, {
+      cwd: repoRoot,
+      encoding: "utf8",
+      timeout: timeoutMs,
+      stdio: ["ignore", "pipe", "pipe"]
+    });
+    return {
+      command: [command, ...args].join(" "),
+      exitCode: 0,
+      stdout: stdout.slice(0, maxChars)
+    };
+  } catch (error) {
+    return {
+      command: [command, ...args].join(" "),
+      exitCode: Number.isInteger(error.status) ? error.status : 1,
+      stdout: String(error.stdout ?? "").slice(0, maxChars),
+      stderr: String(error.stderr || error.message || "").slice(0, maxChars)
+    };
+  }
+}
+
+function commandExists(command) {
+  const result = commandResult("bash", ["-lc", `command -v ${command}`], { timeoutMs: 2000 });
+  return result.exitCode === 0 && result.stdout.trim().length > 0;
+}
+
+function collectLocalRuntimeObservations() {
+  const observations = [];
+
+  if (commandExists("docker")) {
+    const docker = commandResult("docker", [
+      "ps",
+      "--format",
+      "{{.Names}}\t{{.Image}}\t{{.Status}}\t{{.Ports}}"
+    ]);
+    const hwlabLines = docker.stdout
+      .split("\n")
+      .filter((line) => line.includes("hwlab-"))
+      .join("\n");
+    observations.push({
+      id: "docker-hwlab-containers",
+      status: hwlabLines ? "observed" : "not_observed",
+      command: docker.command,
+      summary: oneLine(hwlabLines || "No running docker container name/image/port line contained hwlab-.")
+    });
+  } else {
+    observations.push({
+      id: "docker-hwlab-containers",
+      status: "unavailable",
+      command: "command -v docker",
+      summary: "docker CLI is not available in this runner."
+    });
+  }
+
+  if (commandExists("kubectl")) {
+    const kubectl = commandResult("kubectl", ["get", "deploy,po,svc", "-n", namespace, "-o", "wide"]);
+    observations.push({
+      id: "kubectl-hwlab-dev",
+      status: kubectl.exitCode === 0 ? "observed" : "blocked",
+      command: kubectl.command,
+      summary: oneLine(kubectl.exitCode === 0 ? kubectl.stdout : kubectl.stderr || kubectl.stdout)
+    });
+  } else {
+    observations.push({
+      id: "kubectl-hwlab-dev",
+      status: "unavailable",
+      command: "command -v kubectl",
+      summary: "kubectl is not available in this runner, so hwlab-dev namespace state was not observed."
+    });
+  }
+
+  return observations;
+}
+
+async function probeJson(url, options = {}) {
+  const method = options.method ?? "GET";
+  const startedAt = isoNow();
+  const timeoutMs = options.timeoutMs ?? 8000;
+  const body = options.body ? JSON.stringify(options.body) : null;
+  const headers = body
+    ? {
+        "content-type": "application/json",
+        "content-length": Buffer.byteLength(body)
+      }
+    : {};
+
+  return new Promise((resolve) => {
+    const parsed = new URL(url);
+    const requestFn = parsed.protocol === "https:" ? httpsRequest : httpRequest;
+    const req = requestFn(
+      parsed,
+      {
+        method,
+        headers,
+        timeout: timeoutMs
+      },
+      (response) => {
+        let text = "";
+        response.setEncoding("utf8");
+        response.on("data", (chunk) => {
+          text += chunk;
+        });
+        response.on("end", () => {
+          let json = null;
+          try {
+            json = text ? JSON.parse(text) : null;
+          } catch {
+            json = null;
+          }
+          const status = response.statusCode ?? 0;
+          resolve({
+            url,
+            method,
+            startedAt,
+            observedAt: isoNow(),
+            reached: true,
+            ok: status >= 200 && status < 300,
+            status,
+            statusText: response.statusMessage ?? "",
+            json,
+            bodyPreview: json ? undefined : text.slice(0, 500)
+          });
+        });
+      }
+    );
+
+    req.on("timeout", () => {
+      req.destroy(new Error(`request timed out after ${timeoutMs}ms`));
+    });
+
+    req.on("error", (error) => {
+      resolve({
+        url,
+        method,
+        startedAt,
+        observedAt: isoNow(),
+        reached: false,
+        ok: false,
+        error: {
+          name: error.name,
+          message: error.message,
+          code: error.code
+        }
+      });
+    });
+
+    if (body) {
+      req.write(body);
+    }
+    req.end();
+  });
+}
+
+function joinUrl(baseUrl, routePath) {
+  return new URL(routePath, baseUrl.endsWith("/") ? baseUrl : `${baseUrl}/`).toString();
+}
+
+function isHwlabDevIdentity(probe) {
+  const body = probe.json;
+  if (!probe.ok || !body || typeof body !== "object" || Array.isArray(body)) {
+    return false;
+  }
+  if (typeof body.serviceId !== "string" || !body.serviceId.startsWith("hwlab-")) {
+    return false;
+  }
+  return body.environment === undefined || body.environment === ENVIRONMENT_DEV;
+}
+
+async function observeDevIngress() {
+  const paths = ["/health/live", "/health", "/live", "/v1"];
+  const probes = [];
+  for (const routePath of paths) {
+    probes.push(await probeJson(joinUrl(DEV_ENDPOINT, routePath)));
+  }
+
+  const accepted = probes.find(isHwlabDevIdentity);
+  return {
+    accepted: Boolean(accepted),
+    acceptedPath: accepted ? new URL(accepted.url).pathname : null,
+    probes
+  };
+}
+
+function targetMapFromEnvironment() {
+  const missing = [];
+  const targets = new Map();
+
+  for (const target of serviceTargets) {
+    const baseUrl = process.env[target.urlEnv];
+    if (!baseUrl) {
+      missing.push(target.urlEnv);
+      continue;
+    }
+    targets.set(target.id, {
+      ...target,
+      baseUrl
+    });
+  }
+
+  return { missing, targets };
+}
+
+function assertBoxState(state, label) {
+  assert.equal(state?.serviceId, "hwlab-box-simu", `${label} serviceId`);
+  assert.equal(state.live, true, `${label} live`);
+  assert.equal(state.resource?.environment ?? state.environment, ENVIRONMENT_DEV, `${label} environment`);
+  assert.ok(state.ports?.DO1, `${label} requires DO1`);
+  assert.ok(state.ports?.DI1, `${label} requires DI1`);
+  assert.equal(state.constraints?.crossDevicePropagation, "patch-panel-only", `${label} propagation`);
+  assert.equal(state.constraints?.localLoopbackEnabled, false, `${label} local loopback`);
+}
+
+function assertGatewayState(state, label) {
+  assert.equal(state?.serviceId, "hwlab-gateway-simu", `${label} serviceId`);
+  assert.equal(state.live, true, `${label} live`);
+  assert.equal(state.session?.status, "connected", `${label} session status`);
+  assert.equal(state.session?.environment, ENVIRONMENT_DEV, `${label} environment`);
+  assert.ok(Array.isArray(state.boxes) && state.boxes.length >= 1, `${label} boxes`);
+}
+
+function assertPatchPanelStatus(state) {
+  assert.equal(state?.serviceId, "hwlab-patch-panel", "patch-panel serviceId");
+  assert.equal(state.state, "active", "patch-panel state");
+  assert.equal(state.environment, ENVIRONMENT_DEV, "patch-panel environment");
+  assert.ok(Array.isArray(state.activeConnections), "patch-panel activeConnections");
+}
+
+function findM3Connection({ status, wiring, box1, box2 }) {
+  const fromResourceId = box1.resource?.resourceId;
+  const toResourceId = box2.resource?.resourceId;
+  const activeConnections = status.activeConnections ?? [];
+  const wiringConnections = wiring.connections ?? [];
+
+  const active = activeConnections.find(
+    (connection) =>
+      connection.fromResourceId === fromResourceId &&
+      connection.fromPort === "DO1" &&
+      connection.toResourceId === toResourceId &&
+      connection.toPort === "DI1"
+  );
+  const configured = wiringConnections.find(
+    (connection) =>
+      connection.from?.resourceId === fromResourceId &&
+      connection.from?.port === "DO1" &&
+      connection.to?.resourceId === toResourceId &&
+      connection.to?.port === "DI1" &&
+      connection.mode === "exclusive"
+  );
+
+  return { active, configured };
+}
+
+async function runLiveM3Targets(targets) {
+  const observed = {};
+  const probes = [];
+
+  for (const [id, target] of targets.entries()) {
+    const health = await probeJson(joinUrl(target.baseUrl, "/health/live"));
+    const status = await probeJson(joinUrl(target.baseUrl, target.statusPath));
+    probes.push({ id, kind: "health", probe: health }, { id, kind: "status", probe: status });
+    assert.ok(health.ok, `${id} health failed`);
+    assert.ok(status.ok, `${id} status failed`);
+    assert.equal(health.json?.serviceId, target.serviceId, `${id} health serviceId`);
+    observed[id] = status.json;
+  }
+
+  assertBoxState(observed["box-simu-1"], "box-simu-1");
+  assertBoxState(observed["box-simu-2"], "box-simu-2");
+  assertGatewayState(observed["gateway-simu-1"], "gateway-simu-1");
+  assertGatewayState(observed["gateway-simu-2"], "gateway-simu-2");
+  assertPatchPanelStatus(observed["patch-panel"]);
+
+  const patchTarget = targets.get("patch-panel");
+  const wiring = await probeJson(joinUrl(patchTarget.baseUrl, patchTarget.wiringPath));
+  probes.push({ id: "patch-panel", kind: "wiring", probe: wiring });
+  assert.ok(wiring.ok, "patch-panel wiring failed");
+  assert.equal(wiring.json?.status, "active", "wiring status");
+  assert.equal(wiring.json?.constraints?.propagation, "patch-panel-only", "wiring propagation");
+
+  const connection = findM3Connection({
+    status: observed["patch-panel"],
+    wiring: wiring.json,
+    box1: observed["box-simu-1"],
+    box2: observed["box-simu-2"]
+  });
+  assert.ok(connection.active, "patch-panel active DO1 -> DI1 connection missing");
+  assert.ok(connection.configured, "wiring config DO1 -> DI1 connection missing");
+
+  const operationId = `op_dev_m3_${randomUUID()}`;
+  const traceId = `trc_dev_m3_${randomUUID()}`;
+  const box1Target = targets.get("box-simu-1");
+  const box2Target = targets.get("box-simu-2");
+
+  const write = await probeJson(joinUrl(box1Target.baseUrl, "/ports/write"), {
+    method: "POST",
+    body: {
+      port: "DO1",
+      value: true,
+      operationId,
+      traceId
+    }
+  });
+  probes.push({ id: "box-simu-1", kind: "do.write", probe: write });
+  assert.ok(write.ok, "box-simu-1 DO1 write failed");
+  assert.equal(write.json?.accepted, true, "box-simu-1 DO1 write accepted");
+
+  const route = await probeJson(joinUrl(patchTarget.baseUrl, patchTarget.routePath), {
+    method: "POST",
+    body: {
+      fromResourceId: observed["box-simu-1"].resource.resourceId,
+      fromPort: "DO1",
+      value: true,
+      operationId,
+      traceId
+    }
+  });
+  probes.push({ id: "patch-panel", kind: "signals.route", probe: route });
+  assert.ok(route.ok, "patch-panel signal route failed");
+  assert.equal(route.json?.accepted, true, "patch-panel signal route accepted");
+  assert.equal(route.json?.deliveryCount, 1, "patch-panel signal route delivery count");
+
+  const after = await probeJson(joinUrl(box2Target.baseUrl, "/status"));
+  probes.push({ id: "box-simu-2", kind: "di.read", probe: after });
+  assert.ok(after.ok, "box-simu-2 DI1 read failed");
+  assert.equal(after.json?.ports?.DI1?.value, true, "box-simu-2 DI1 must read true");
+
+  const auditId = route.json?.auditId ?? write.json?.auditId ?? after.json?.auditId;
+  const evidenceId = route.json?.evidenceId ?? write.json?.evidenceId ?? after.json?.evidenceId;
+  assert.equal(typeof auditId, "string", "live M3 result must include auditId");
+  assert.equal(typeof evidenceId, "string", "live M3 result must include evidenceId");
+
+  return {
+    operationId,
+    traceId,
+    auditId,
+    evidenceId,
+    probes,
+    observed
+  };
+}
+
+function baseReport({ commitId, observedAt }) {
+  return {
+    $schema: "https://hwlab.pikastech.local/schemas/dev-m3-hardware-loop-report.schema.json",
+    $id: "https://hwlab.pikastech.local/reports/dev-gate/dev-m3-hardware-loop.json",
+    reportVersion: "v1",
+    issue,
+    taskId: "dev-m3-hardware-loop",
+    commitId,
+    acceptanceLevel: "dev_m3_hardware_loop",
+    devOnly: true,
+    prodDisabled: true,
+    sourceContract: {
+      status: "pass",
+      documents: [
+        "docs/dev-acceptance-matrix.md",
+        "docs/m3-hardware-loop.md",
+        "fixtures/mvp/m3-hardware-loop/topology.json"
+      ],
+      summary: "Source contracts define DEV-only M3 simulator wiring and prohibit fixture output as live evidence."
+    },
+    validationCommands: [
+      "node --check scripts/dev-m3-hardware-loop-smoke.mjs",
+      "node scripts/dev-m3-hardware-loop-smoke.mjs --live --confirm-dev --confirmed-non-production",
+      "node --check scripts/validate-dev-gate-report.mjs",
+      "node scripts/validate-dev-gate-report.mjs"
+    ],
+    runtimeTarget: {
+      endpoint: DEV_ENDPOINT,
+      namespace,
+      environment: ENVIRONMENT_DEV,
+      requiredBoxSimulators: 2,
+      requiredGatewaySimulators: 2,
+      realHardwareAllowed: false,
+      prodAllowed: false
+    },
+    safetyGates: {
+      liveFlagRequired: true,
+      confirmDevRequired: true,
+      confirmedNonProductionRequired: true,
+      prodForbidden: true,
+      realHardwareForbidden: true,
+      secretReadForbidden: true,
+      forcePushForbidden: true,
+      unideskRuntimeSubstitutionForbidden: true
+    },
+    liveChecks: [
+      {
+        id: "static-contract-parse",
+        status: "pass",
+        summary: "DEV M3 smoke contract files were readable before live probing.",
+        evidence: [
+          "docs/dev-acceptance-matrix.md",
+          "docs/m3-hardware-loop.md"
+        ]
+      },
+      {
+        id: "endpoint-freeze",
+        status: "pass",
+        summary: `DEV endpoint is frozen at ${DEV_ENDPOINT}.`,
+        evidence: [DEV_ENDPOINT]
+      }
+    ],
+    localRuntimeObservations: [],
+    liveOperation: {
+      status: "not_run",
+      operationId: "not_observed",
+      traceId: "not_observed",
+      auditId: "not_observed",
+      evidenceId: "not_observed",
+      summary: "No live DEV operation has run yet."
+    },
+    blockers: [],
+    summary: {
+      status: "not_run",
+      observedAt,
+      result: "DEV M3 smoke has not completed."
+    }
+  };
+}
+
+function addNotRunM3Checks(report, reason) {
+  for (const id of [
+    "two-box-simu-online",
+    "two-gateway-simu-online",
+    "patch-panel-healthy",
+    "wiring-do1-di1-applied",
+    "direct-call-do-write-di-read",
+    "audit-evidence-traceable"
+  ]) {
+    report.liveChecks.push({
+      id,
+      status: "not_run",
+      summary: reason,
+      evidence: ["No live DEV evidence collected for this check."]
+    });
+  }
+}
+
+async function ensureContractFiles() {
+  await access(path.join(repoRoot, "docs/dev-acceptance-matrix.md"));
+  await access(path.join(repoRoot, "docs/m3-hardware-loop.md"));
+  await access(path.join(repoRoot, "fixtures/mvp/m3-hardware-loop/topology.json"));
+}
+
+async function writeReport(report, reportPath) {
+  await mkdir(path.dirname(reportPath), { recursive: true });
+  await writeFile(reportPath, `${JSON.stringify(report, null, 2)}\n`, "utf8");
+}
+
+async function main() {
+  const { flags, values } = parseArgs(process.argv.slice(2));
+  requireSafetyGates(flags);
+  await ensureContractFiles();
+
+  const reportPath = resolveReportPath(values.get("output"));
+  const observedAt = isoNow();
+  const report = baseReport({
+    commitId: currentCommit(),
+    observedAt
+  });
+
+  const ingress = await observeDevIngress();
+  report.localRuntimeObservations = collectLocalRuntimeObservations();
+  report.liveChecks.push({
+    id: "dev-ingress-health",
+    status: ingress.accepted ? "pass" : "blocked",
+    blockerClass: ingress.accepted ? undefined : "network_blocker",
+    summary: ingress.accepted
+      ? `DEV ingress returned HWLAB identity at ${ingress.acceptedPath}.`
+      : `DEV ingress at ${DEV_ENDPOINT} did not return reachable HWLAB DEV health.`,
+    evidence: ingress.probes.map((probe) => JSON.stringify(probe))
+  });
+
+  if (!ingress.accepted) {
+    addNotRunM3Checks(report, "Stopped at DEV ingress per the DEV smoke matrix.");
+    report.liveOperation = {
+      status: "not_run",
+      operationId: "not_observed",
+      traceId: "not_observed",
+      auditId: "not_observed",
+      evidenceId: "not_observed",
+      summary: "No live do.write -> di.read operation was attempted because DEV ingress is blocked."
+    };
+    report.blockers.push({
+      type: "network_blocker",
+      scope: "dev-ingress-health",
+      status: "open",
+      summary: "Blocked at the #33 DEV runtime readiness condition: public DEV ingress does not accept HWLAB health requests, so #36/M3 hardware-loop checks were not reached."
+    });
+    report.summary = {
+      status: "blocked",
+      observedAt,
+      result: "No live DEV M3 evidence was produced; fixture-backed local evidence was not used as a substitute."
+    };
+    await writeReport(report, reportPath);
+    console.log(`[dev-m3-smoke] status=blocked report=${relativePath(reportPath)}`);
+    console.log("[dev-m3-smoke] blocker=network_blocker scope=dev-ingress-health");
+    return;
+  }
+
+  const { missing, targets } = targetMapFromEnvironment();
+  if (missing.length > 0) {
+    addNotRunM3Checks(report, "Stopped before M3 direct checks because service target URLs were not provided.");
+    report.blockers.push({
+      type: "runtime_blocker",
+      scope: "m3-service-discovery",
+      status: "open",
+      summary: `DEV ingress is reachable, but M3 smoke lacks direct DEV service URLs: ${missing.join(", ")}.`
+    });
+    report.summary = {
+      status: "blocked",
+      observedAt,
+      result: "DEV ingress was reachable, but live M3 simulator and patch-panel targets were not discoverable."
+    };
+    await writeReport(report, reportPath);
+    console.log(`[dev-m3-smoke] status=blocked report=${relativePath(reportPath)}`);
+    console.log("[dev-m3-smoke] blocker=runtime_blocker scope=m3-service-discovery");
+    return;
+  }
+
+  try {
+    const live = await runLiveM3Targets(targets);
+    report.liveChecks.push(
+      {
+        id: "two-box-simu-online",
+        status: "pass",
+        summary: "Both DEV box simulators reported live status with DO1 and DI1 ports.",
+        evidence: ["box-simu-1 /status", "box-simu-2 /status"]
+      },
+      {
+        id: "two-gateway-simu-online",
+        status: "pass",
+        summary: "Both DEV gateway simulators reported connected sessions.",
+        evidence: ["gateway-simu-1 /status", "gateway-simu-2 /status"]
+      },
+      {
+        id: "patch-panel-healthy",
+        status: "pass",
+        summary: "DEV patch-panel reported active status.",
+        evidence: ["patch-panel /status"]
+      },
+      {
+        id: "wiring-do1-di1-applied",
+        status: "pass",
+        summary: "Patch-panel active wiring matched box-simu-1 DO1 -> box-simu-2 DI1.",
+        evidence: ["patch-panel /wiring"]
+      },
+      {
+        id: "direct-call-do-write-di-read",
+        status: "pass",
+        summary: "Live DEV direct call observed do.write true followed by di.read true.",
+        evidence: [`operationId=${live.operationId}`, `traceId=${live.traceId}`]
+      },
+      {
+        id: "audit-evidence-traceable",
+        status: "pass",
+        summary: "Live DEV direct call returned audit and evidence identifiers.",
+        evidence: [`auditId=${live.auditId}`, `evidenceId=${live.evidenceId}`]
+      }
+    );
+    report.liveOperation = {
+      status: "pass",
+      operationId: live.operationId,
+      traceId: live.traceId,
+      auditId: live.auditId,
+      evidenceId: live.evidenceId,
+      summary: "Live DEV M3 do.write true -> di.read true succeeded with traceable audit/evidence identifiers."
+    };
+    report.rawLiveProbeCount = live.probes.length;
+    report.summary = {
+      status: "pass",
+      observedAt,
+      result: "Live DEV M3 hardware loop passed without fixture substitution."
+    };
+    await writeReport(report, reportPath);
+    console.log(`[dev-m3-smoke] status=pass report=${relativePath(reportPath)}`);
+    console.log(
+      `[dev-m3-smoke] operationId=${live.operationId} auditId=${live.auditId} evidenceId=${live.evidenceId}`
+    );
+  } catch (error) {
+    addNotRunM3Checks(report, "A live DEV M3 runtime contract check failed before all checks passed.");
+    report.blockers.push({
+      type: "runtime_blocker",
+      scope: "m3-hardware-loop-runtime",
+      status: "open",
+      summary: error instanceof Error ? error.message : String(error)
+    });
+    report.summary = {
+      status: "blocked",
+      observedAt,
+      result: "Live DEV M3 runtime was reachable but did not satisfy the M3 hardware-loop contract."
+    };
+    await writeReport(report, reportPath);
+    console.log(`[dev-m3-smoke] status=blocked report=${relativePath(reportPath)}`);
+    console.log("[dev-m3-smoke] blocker=runtime_blocker scope=m3-hardware-loop-runtime");
+  }
+}
+
+try {
+  await main();
+} catch (error) {
+  console.error(`[dev-m3-smoke] ${error instanceof Error ? error.message : String(error)}`);
+  process.exitCode = 1;
+}
diff --git a/scripts/validate-dev-gate-report.mjs b/scripts/validate-dev-gate-report.mjs
index a45195da..2b26866d 100644
--- a/scripts/validate-dev-gate-report.mjs
+++ b/scripts/validate-dev-gate-report.mjs
@@ -20,6 +20,15 @@ const requiredDocs = [
   "docs/dev-acceptance-matrix.md",
   "docs/m0-contract-audit.md"
 ];
+const requiredDevM3Issue = "pikasTech/HWLAB#38";
+const requiredDevM3ValidationCommands = [
+  "node --check scripts/dev-m3-hardware-loop-smoke.mjs",
+  "node scripts/dev-m3-hardware-loop-smoke.mjs --live --confirm-dev --confirmed-non-production"
+];
+const requiredDevM3Docs = [
+  "docs/dev-acceptance-matrix.md",
+  "docs/m3-hardware-loop.md"
+];
 
 const statusValues = new Set(["pass", "blocked", "not_run", "not_applicable", "failed"]);
 const blockerTypes = new Set([
@@ -52,6 +61,11 @@ function assertStatus(value, label) {
   assert.ok(statusValues.has(value), `${label} must be one of ${Array.from(statusValues).join(", ")}`);
 }
 
+function assertTimestamp(value, label) {
+  assertString(value, label);
+  assert.ok(!Number.isNaN(Date.parse(value)), `${label} must be an RFC 3339 timestamp`);
+}
+
 function assertRepoRelativePath(value, label) {
   assertString(value, label);
   assert.ok(!path.isAbsolute(value), `${label} must be repo-relative`);
@@ -96,6 +110,11 @@ async function validateReport(relativePath) {
   const label = relativePath;
 
   assertObject(report, label);
+  if (report.issue === requiredDevM3Issue || report.taskId === "dev-m3-hardware-loop") {
+    await validateDevM3Report(report, label);
+    return;
+  }
+
   for (const field of [
     "$schema",
     "$id",
@@ -206,6 +225,149 @@ async function validateReport(relativePath) {
   }
 }
 
+async function validateDevM3Report(report, label) {
+  for (const field of [
+    "$schema",
+    "$id",
+    "reportVersion",
+    "issue",
+    "taskId",
+    "commitId",
+    "acceptanceLevel",
+    "devOnly",
+    "prodDisabled",
+    "sourceContract",
+    "validationCommands",
+    "runtimeTarget",
+    "safetyGates",
+    "liveChecks",
+    "liveOperation",
+    "blockers",
+    "summary"
+  ]) {
+    assert.ok(Object.hasOwn(report, field), `${label} missing ${field}`);
+  }
+
+  assertString(report.$schema, `${label}.$schema`);
+  assertString(report.$id, `${label}.$id`);
+  assert.equal(report.reportVersion, "v1", `${label}.reportVersion`);
+  assert.equal(report.issue, requiredDevM3Issue, `${label}.issue`);
+  assert.equal(report.taskId, "dev-m3-hardware-loop", `${label}.taskId`);
+  assert.match(report.commitId, /^([a-f0-9]{7,40}|unknown)$/, `${label}.commitId`);
+  assert.equal(report.acceptanceLevel, "dev_m3_hardware_loop", `${label}.acceptanceLevel`);
+  assert.equal(report.devOnly, true, `${label}.devOnly`);
+  assert.equal(report.prodDisabled, true, `${label}.prodDisabled`);
+
+  assertObject(report.sourceContract, `${label}.sourceContract`);
+  assertStatus(report.sourceContract.status, `${label}.sourceContract.status`);
+  assertStringArray(report.sourceContract.documents, `${label}.sourceContract.documents`, {
+    minLength: requiredDevM3Docs.length
+  });
+  assertString(report.sourceContract.summary, `${label}.sourceContract.summary`);
+  const documents = new Set(report.sourceContract.documents);
+  assertUnique(report.sourceContract.documents, `${label}.sourceContract.documents`);
+  for (const requiredDoc of requiredDevM3Docs) {
+    assert.ok(documents.has(requiredDoc), `${label}.sourceContract.documents missing ${requiredDoc}`);
+  }
+  for (const [index, documentPath] of report.sourceContract.documents.entries()) {
+    const absolutePath = assertRepoRelativePath(
+      documentPath,
+      `${label}.sourceContract.documents[${index}]`
+    );
+    await access(absolutePath, fsConstants.R_OK);
+  }
+
+  assertStringArray(report.validationCommands, `${label}.validationCommands`, { minLength: 2 });
+  assertUnique(report.validationCommands, `${label}.validationCommands`);
+  for (const requiredCommand of requiredDevM3ValidationCommands) {
+    assert.ok(
+      report.validationCommands.includes(requiredCommand),
+      `${label}.validationCommands missing ${requiredCommand}`
+    );
+  }
+
+  assertObject(report.runtimeTarget, `${label}.runtimeTarget`);
+  assert.equal(report.runtimeTarget.endpoint, "http://74.48.78.17:6667", `${label}.runtimeTarget.endpoint`);
+  assert.equal(report.runtimeTarget.namespace, "hwlab-dev", `${label}.runtimeTarget.namespace`);
+  assert.equal(report.runtimeTarget.environment, "dev", `${label}.runtimeTarget.environment`);
+  assert.equal(report.runtimeTarget.requiredBoxSimulators, 2, `${label}.runtimeTarget.requiredBoxSimulators`);
+  assert.equal(report.runtimeTarget.requiredGatewaySimulators, 2, `${label}.runtimeTarget.requiredGatewaySimulators`);
+  assert.equal(report.runtimeTarget.realHardwareAllowed, false, `${label}.runtimeTarget.realHardwareAllowed`);
+  assert.equal(report.runtimeTarget.prodAllowed, false, `${label}.runtimeTarget.prodAllowed`);
+
+  assertObject(report.safetyGates, `${label}.safetyGates`);
+  for (const field of [
+    "liveFlagRequired",
+    "confirmDevRequired",
+    "confirmedNonProductionRequired",
+    "prodForbidden",
+    "realHardwareForbidden",
+    "secretReadForbidden",
+    "forcePushForbidden",
+    "unideskRuntimeSubstitutionForbidden"
+  ]) {
+    assert.equal(report.safetyGates[field], true, `${label}.safetyGates.${field}`);
+  }
+
+  assertArray(report.liveChecks, `${label}.liveChecks`);
+  assert.ok(report.liveChecks.length >= 8, `${label}.liveChecks must include DEV M3 checks`);
+  assertUnique(report.liveChecks.map((check) => check.id), `${label}.liveChecks`);
+  for (const [index, check] of report.liveChecks.entries()) {
+    const checkLabel = `${label}.liveChecks[${index}]`;
+    assertObject(check, checkLabel);
+    for (const field of ["id", "status", "summary", "evidence"]) {
+      assert.ok(Object.hasOwn(check, field), `${checkLabel} missing ${field}`);
+    }
+    assertString(check.id, `${checkLabel}.id`);
+    assertStatus(check.status, `${checkLabel}.status`);
+    assertString(check.summary, `${checkLabel}.summary`);
+    assertStringArray(check.evidence, `${checkLabel}.evidence`, { minLength: 1 });
+    if (Object.hasOwn(check, "blockerClass")) {
+      assert.ok(blockerTypes.has(check.blockerClass), `${checkLabel}.blockerClass must be known`);
+    }
+  }
+
+  if (Object.hasOwn(report, "localRuntimeObservations")) {
+    assertArray(report.localRuntimeObservations, `${label}.localRuntimeObservations`);
+    for (const [index, observation] of report.localRuntimeObservations.entries()) {
+      const observationLabel = `${label}.localRuntimeObservations[${index}]`;
+      assertObject(observation, observationLabel);
+      for (const field of ["id", "status", "command", "summary"]) {
+        assert.ok(Object.hasOwn(observation, field), `${observationLabel} missing ${field}`);
+        assertString(observation[field], `${observationLabel}.${field}`);
+      }
+    }
+  }
+
+  assertObject(report.liveOperation, `${label}.liveOperation`);
+  assertStatus(report.liveOperation.status, `${label}.liveOperation.status`);
+  for (const field of ["operationId", "traceId", "auditId", "evidenceId", "summary"]) {
+    assertString(report.liveOperation[field], `${label}.liveOperation.${field}`);
+  }
+
+  assertArray(report.blockers, `${label}.blockers`);
+  assertUnique(
+    report.blockers.map((blocker) => `${blocker.type}::${blocker.scope}`),
+    `${label}.blockers`
+  );
+  for (const [index, blocker] of report.blockers.entries()) {
+    const blockerLabel = `${label}.blockers[${index}]`;
+    assertObject(blocker, blockerLabel);
+    for (const field of ["type", "scope", "status", "summary"]) {
+      assert.ok(Object.hasOwn(blocker, field), `${blockerLabel} missing ${field}`);
+    }
+    assert.ok(blockerTypes.has(blocker.type), `${blockerLabel}.type must be a known blocker type`);
+    assertString(blocker.scope, `${blockerLabel}.scope`);
+    assert.ok(blockerStates.has(blocker.status), `${blockerLabel}.status must be open, acknowledged, or closed`);
+    assertString(blocker.summary, `${blockerLabel}.summary`);
+  }
+
+  assertObject(report.summary, `${label}.summary`);
+  assertStatus(report.summary.status, `${label}.summary.status`);
+  assertTimestamp(report.summary.observedAt, `${label}.summary.observedAt`);
+  assertString(report.summary.result, `${label}.summary.result`);
+}
+
 async function main() {
   const reportFiles = await collectReportFiles();
   assert.ok(reportFiles.length >= 1, "expected at least one dev-gate report JSON file");