diff --git a/src/lib/onboard.ts b/src/lib/onboard.ts
index bff72aafa4..eb9fb7c58c 100644
--- a/src/lib/onboard.ts
+++ b/src/lib/onboard.ts
@@ -430,6 +430,8 @@ const { applyPreflightGatewayCleanup } =
   require("./onboard/preflight-gateway-cleanup-decision") as typeof import("./onboard/preflight-gateway-cleanup-decision");
 const { verifyGatewayContainerRunning } =
   require("./onboard/gateway-container-running") as typeof import("./onboard/gateway-container-running");
+const { applyHealthyPortReuse } =
+  require("./onboard/gateway-stale-port-reuse") as typeof import("./onboard/gateway-stale-port-reuse");
 const { destroyGatewayWithVolumeCleanup } =
   require("./onboard/gateway-destroy") as typeof import("./onboard/gateway-destroy");
 const {
@@ -2235,12 +2237,9 @@ async function preflight(
       port === GATEWAY_PORT ? dockerDriverGatewayEnv.getGatewayPortCheckOptions() : undefined;
     let portCheck = await checkPortAvailable(port, portCheckOptions);
     if (!portCheck.ok) {
-      if ((port === GATEWAY_PORT || port === DASHBOARD_PORT) && gatewayReuseState === "healthy") {
-        console.log(
-          `  ✓ Port ${port} already owned by healthy ${cliDisplayName()} runtime (${label})`,
-        );
-        continue;
-      }
+      const reuse = await applyHealthyPortReuse({ port, gatewayPort: GATEWAY_PORT, dashboardPort: DASHBOARD_PORT, label, runtimeDisplayName: cliDisplayName(), gatewayName: GATEWAY_NAME, gatewayReuseState, portCheckOptions, supportsLifecycleCommands: gatewayCliSupportsLifecycleCommands(runCaptureOpenshell), destroyGateway, runOpenshell, checkPortAvailable, verifyGatewayContainerRunning });
+      if (reuse === "continue") continue;
+      if (reuse) { ({ gatewayReuseState, portCheck } = reuse); if (portCheck.ok) continue; }
       if (port === GATEWAY_PORT) {
         const dockerGatewayPid = getDockerDriverGatewayPortListenerPid(portCheck);
         if (dockerGatewayPid !== null) {
diff --git a/src/lib/onboard/gateway-stale-port-reuse.test.ts b/src/lib/onboard/gateway-stale-port-reuse.test.ts
new file mode 100644
index 0000000000..5469488b43
--- /dev/null
+++ b/src/lib/onboard/gateway-stale-port-reuse.test.ts
@@ -0,0 +1,234 @@
+// SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+import { afterEach, describe, expect, it, vi } from "vitest";
+
+import type { GatewayReuseState } from "../state/gateway";
+import type { GatewayContainerState } from "./gateway-container-running";
+import { applyHealthyPortReuse, classifyGatewayPortReuse } from "./gateway-stale-port-reuse";
+
+const NON_HEALTHY_STATES: GatewayReuseState[] = [
+  "active-unnamed",
+  "foreign-active",
+  "stale",
+  "missing",
+];
+
+describe("classifyGatewayPortReuse", () => {
+  it("returns stale when recorded healthy but the legacy container is missing", () => {
+    expect(
+      classifyGatewayPortReuse({
+        gatewayReuseState: "healthy",
+        supportsLifecycleCommands: true,
+        containerState: "missing",
+      }),
+    ).toBe("stale");
+  });
+
+  it("returns reuse when recorded healthy and the container is live", () => {
+    expect(
+      classifyGatewayPortReuse({
+        gatewayReuseState: "healthy",
+        supportsLifecycleCommands: true,
+        containerState: "running",
+      }),
+    ).toBe("reuse");
+  });
+
+  it("returns reuse when recorded healthy and the container probe was inconclusive", () => {
+    expect(
+      classifyGatewayPortReuse({
+        gatewayReuseState: "healthy",
+        supportsLifecycleCommands: true,
+        containerState: "unknown",
+      }),
+    ).toBe("reuse");
+  });
+
+  it("returns reuse when the CLI lacks lifecycle commands, regardless of container state", () => {
+    for (const containerState of ["missing", "running", "unknown"] as GatewayContainerState[]) {
+      expect(
+        classifyGatewayPortReuse({
+          gatewayReuseState: "healthy",
+          supportsLifecycleCommands: false,
+          containerState,
+        }),
+      ).toBe("reuse");
+    }
+  });
+
+  it("returns skip for any non-healthy recorded state", () => {
+    for (const gatewayReuseState of NON_HEALTHY_STATES) {
+      expect(
+        classifyGatewayPortReuse({
+          gatewayReuseState,
+          supportsLifecycleCommands: true,
+          containerState: "missing",
+        }),
+      ).toBe("skip");
+    }
+  });
+});
+
+const BASE_INPUT = {
+  port: 8080,
+  gatewayPort: 8080,
+  dashboardPort: 18789,
+  label: "OpenShell gateway",
+  runtimeDisplayName: "NemoClaw",
+  gatewayName: "nemoclaw",
+  gatewayReuseState: "healthy" as GatewayReuseState,
+  portCheckOptions: undefined,
+  supportsLifecycleCommands: true,
+};
+
+describe("applyHealthyPortReuse", () => {
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  it("returns null when recorded state is not healthy", async () => {
+    const result = await applyHealthyPortReuse({
+      ...BASE_INPUT,
+      gatewayReuseState: "missing",
+      destroyGateway: () => true,
+      runOpenshell: vi.fn(),
+      checkPortAvailable: vi.fn(),
+      verifyGatewayContainerRunning: vi.fn(),
+    });
+    expect(result).toBeNull();
+  });
+
+  it("returns null for ports that are neither the gateway nor dashboard port", async () => {
+    const result = await applyHealthyPortReuse({
+      ...BASE_INPUT,
+      port: 9999,
+      destroyGateway: () => true,
+      runOpenshell: vi.fn(),
+      checkPortAvailable: vi.fn(),
+      verifyGatewayContainerRunning: vi.fn(),
+    });
+    expect(result).toBeNull();
+  });
+
+  it("cleans up stale metadata and returns downgraded state when the port frees up", async () => {
+    const log = vi.spyOn(console, "log").mockImplementation(() => undefined);
+    const destroyGateway = vi.fn(() => true);
+    const runOpenshell = vi.fn();
+    const checkPortAvailable = vi.fn().mockResolvedValue({ ok: true });
+
+    const result = await applyHealthyPortReuse({
+      ...BASE_INPUT,
+      destroyGateway,
+      runOpenshell,
+      checkPortAvailable,
+      verifyGatewayContainerRunning: () => "missing",
+    });
+
+    expect(result).not.toBe("continue");
+    expect(result).not.toBeNull();
+    if (result && result !== "continue") {
+      // Caller must see the downgraded reuse state even when the port frees up,
+      // so downstream branches don't keep treating the runtime as healthy.
+      expect(result.gatewayReuseState).toBe("missing");
+      expect(result.portCheck.ok).toBe(true);
+    }
+    expect(destroyGateway).toHaveBeenCalledTimes(1);
+    expect(runOpenshell).toHaveBeenCalledWith(["forward", "stop", "18789"], { ignoreError: true });
+    expect(checkPortAvailable).toHaveBeenCalledWith(8080, undefined);
+    const messages = log.mock.calls.map((c) => c[0]);
+    expect(messages).toContain("  Gateway metadata is stale (container not running). Cleaning up...");
+    expect(messages).toContain("  ✓ Port 8080 available (OpenShell gateway)");
+  });
+
+  it("returns fall-through state when cleanup succeeds but the port is still busy", async () => {
+    vi.spyOn(console, "log").mockImplementation(() => undefined);
+    const checkPortAvailable = vi.fn().mockResolvedValue({ ok: false });
+
+    const result = await applyHealthyPortReuse({
+      ...BASE_INPUT,
+      destroyGateway: () => true,
+      runOpenshell: vi.fn(),
+      checkPortAvailable,
+      verifyGatewayContainerRunning: () => "missing",
+    });
+
+    expect(result).not.toBeNull();
+    expect(result).not.toBe("continue");
+    if (result && result !== "continue") {
+      expect(result.gatewayReuseState).toBe("missing");
+      expect(result.portCheck.ok).toBe(false);
+    }
+  });
+
+  it("logs the reuse message and continues when the container is live", async () => {
+    const log = vi.spyOn(console, "log").mockImplementation(() => undefined);
+    const destroyGateway = vi.fn(() => true);
+    const checkPortAvailable = vi.fn();
+
+    const result = await applyHealthyPortReuse({
+      ...BASE_INPUT,
+      destroyGateway,
+      runOpenshell: vi.fn(),
+      checkPortAvailable,
+      verifyGatewayContainerRunning: () => "running",
+    });
+
+    expect(result).toBe("continue");
+    expect(destroyGateway).not.toHaveBeenCalled();
+    expect(checkPortAvailable).not.toHaveBeenCalled();
+    const messages = log.mock.calls.map((c) => c[0]);
+    expect(messages).toContain(
+      "  ✓ Port 8080 already owned by healthy NemoClaw runtime (OpenShell gateway)",
+    );
+  });
+
+  it("skips the container probe when lifecycle commands are unsupported", async () => {
+    // Package-managed openshell builds intentionally have no openshell-cluster-*
+    // container. Probing Docker would always return "missing" and the decision
+    // would still come out as "reuse", so the probe is wasted work — worse, in
+    // environments where the docker CLI is flaky the probe can stall onboard.
+    const log = vi.spyOn(console, "log").mockImplementation(() => undefined);
+    const verifyContainer = vi.fn();
+
+    const result = await applyHealthyPortReuse({
+      ...BASE_INPUT,
+      supportsLifecycleCommands: false,
+      destroyGateway: () => true,
+      runOpenshell: vi.fn(),
+      checkPortAvailable: vi.fn(),
+      verifyGatewayContainerRunning: verifyContainer,
+    });
+
+    expect(result).toBe("continue");
+    expect(verifyContainer).not.toHaveBeenCalled();
+    const messages = log.mock.calls.map((c) => c[0]);
+    expect(messages).toContain(
+      "  ✓ Port 8080 already owned by healthy NemoClaw runtime (OpenShell gateway)",
+    );
+  });
+
+  it("reuses the dashboard port without consulting the container", async () => {
+    const log = vi.spyOn(console, "log").mockImplementation(() => undefined);
+    const checkPortAvailable = vi.fn();
+    const verifyContainer = vi.fn();
+
+    const result = await applyHealthyPortReuse({
+      ...BASE_INPUT,
+      port: 18789,
+      label: "NemoClaw dashboard",
+      destroyGateway: () => true,
+      runOpenshell: vi.fn(),
+      checkPortAvailable,
+      verifyGatewayContainerRunning: verifyContainer,
+    });
+
+    expect(result).toBe("continue");
+    expect(verifyContainer).not.toHaveBeenCalled();
+    expect(checkPortAvailable).not.toHaveBeenCalled();
+    const messages = log.mock.calls.map((c) => c[0]);
+    expect(messages).toContain(
+      "  ✓ Port 18789 already owned by healthy NemoClaw runtime (NemoClaw dashboard)",
+    );
+  });
+});
diff --git a/src/lib/onboard/gateway-stale-port-reuse.ts b/src/lib/onboard/gateway-stale-port-reuse.ts
new file mode 100644
index 0000000000..4a5cc239d7
--- /dev/null
+++ b/src/lib/onboard/gateway-stale-port-reuse.ts
@@ -0,0 +1,107 @@
+// SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+import type { GatewayReuseState } from "../state/gateway";
+import { destroyGatewayForReuse } from "./gateway-cleanup";
+import type { GatewayContainerState } from "./gateway-container-running";
+import type { CheckPortOpts, PortProbeResult } from "./preflight";
+
+export type GatewayPortReuseDecision = "stale" | "reuse" | "skip";
+
+export interface GatewayPortReuseInput {
+  gatewayReuseState: GatewayReuseState;
+  supportsLifecycleCommands: boolean;
+  containerState: GatewayContainerState;
+}
+
+// When the preflight port-required check finds the gateway port occupied, the
+// short-circuit in onboard.ts trusts `gatewayReuseState === "healthy"` and
+// reuses the recorded runtime. That short-circuit can fire even after the
+// openshell-cluster-* container has been removed out-of-band (Colima/Docker
+// restart on macOS; manual `docker rm`), because the upstream stale-metadata
+// check that would have cleared the recorded state is gated by
+// `gatewayCliSupportsLifecycleCommands` and can be skipped. (#4268)
+//
+// This decision wraps the second-line defense: when the port is the gateway
+// port and recorded state is "healthy", consult the live container state
+// before reusing. Returns:
+//   - "stale"  — recorded state is "healthy" but the legacy container is
+//                missing; caller should clear registry and re-check the port.
+//   - "reuse"  — recorded state is "healthy" and the container is live (or the
+//                CLI lacks lifecycle commands, so the container model is
+//                package-managed and Docker is not the source of truth).
+//   - "skip"   — recorded state is not "healthy"; this defensive path does not
+//                apply and the caller should fall through to other handling.
+export function classifyGatewayPortReuse(
+  input: GatewayPortReuseInput,
+): GatewayPortReuseDecision {
+  if (input.gatewayReuseState !== "healthy") return "skip";
+  if (!input.supportsLifecycleCommands) return "reuse";
+  if (input.containerState === "missing") return "stale";
+  return "reuse";
+}
+
+export interface HealthyPortReuseInput {
+  port: number;
+  gatewayPort: number;
+  dashboardPort: number;
+  label: string;
+  runtimeDisplayName: string;
+  gatewayName: string;
+  gatewayReuseState: GatewayReuseState;
+  portCheckOptions: CheckPortOpts | undefined;
+  supportsLifecycleCommands: boolean;
+  destroyGateway: () => boolean;
+  runOpenshell: (args: string[], opts: { ignoreError: true }) => unknown;
+  checkPortAvailable: (port?: number, opts?: CheckPortOpts) => Promise<PortProbeResult>;
+  verifyGatewayContainerRunning: (gatewayName: string) => GatewayContainerState;
+}
+
+export type HealthyPortReuseOutcome =
+  | "continue"
+  | { gatewayReuseState: GatewayReuseState; portCheck: PortProbeResult };
+
+// Drive the port-required short-circuit when `gatewayReuseState === "healthy"`.
+// Owns the stale-container detection, registry cleanup, port re-check, and
+// console messaging. Returns `null` when the recorded state isn't reusable
+// (caller should fall through to its usual port-conflict handling); returns
+// "continue" when the loop iteration should be skipped; otherwise returns the
+// updated `gatewayReuseState` plus the re-checked port result so the caller
+// can replay the iteration with fresh state.
+export async function applyHealthyPortReuse(
+  input: HealthyPortReuseInput,
+): Promise<HealthyPortReuseOutcome | null> {
+  const { port, gatewayPort, dashboardPort, label, runtimeDisplayName, gatewayName } = input;
+  if (input.gatewayReuseState !== "healthy") return null;
+  if (port !== gatewayPort && port !== dashboardPort) return null;
+  // Only probe the container when lifecycle commands are advertised — for
+  // package-managed gateways without lifecycle commands the openshell-cluster-*
+  // container intentionally doesn't exist and the probe would always report
+  // "missing", which is then ignored by classifyGatewayPortReuse anyway.
+  if (port === gatewayPort && input.supportsLifecycleCommands) {
+    const decision = classifyGatewayPortReuse({
+      gatewayReuseState: input.gatewayReuseState,
+      supportsLifecycleCommands: true,
+      containerState: input.verifyGatewayContainerRunning(gatewayName),
+    });
+    if (decision === "stale") {
+      console.log("  Gateway metadata is stale (container not running). Cleaning up...");
+      input.runOpenshell(["forward", "stop", String(dashboardPort)], { ignoreError: true });
+      const gatewayReuseState = destroyGatewayForReuse(
+        input.destroyGateway,
+        "  ✓ Stale gateway metadata cleaned up",
+        "  ! Stale gateway metadata cleanup failed; leaving registry state intact.",
+      );
+      const portCheck = await input.checkPortAvailable(port, input.portCheckOptions);
+      if (portCheck.ok) {
+        console.log(`  ✓ Port ${port} available (${label})`);
+      }
+      // Always return the downgraded state so the caller stops treating the
+      // runtime as healthy. The caller uses `portCheck.ok` to decide whether
+      // to continue the loop or fall through to its port-conflict diagnostic.
+      return { gatewayReuseState, portCheck };
+    }
+  }
+  console.log(`  ✓ Port ${port} already owned by healthy ${runtimeDisplayName} runtime (${label})`);
+  return "continue";
+}