fix(cli): prepare Hermes light terminal skin

src/lib/actions/sandbox/connect-hermes-light-theme.test.ts

@@ -0,0 +1,128 @@
+// SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+import { afterEach, beforeEach, describe, expect, it, type MockInstance, vi } from "vitest";
+
+import {
+  connectModulePath,
+  createConnectHarness,
+  requireDist,
+} from "../../../../test/support/connect-flow-test-harness";
+
+describe("Hermes sandbox connect light terminal skin", () => {
+  let exitSpy: MockInstance;
+  const originalStdoutIsTty = process.stdout.isTTY;
+
+  beforeEach(() => {
+    process.env.NEMOCLAW_TEST_NO_SLEEP = "1";
+    Object.defineProperty(process.stdout, "isTTY", { configurable: true, value: true });
+    exitSpy = vi.spyOn(process, "exit").mockImplementation(((code?: number | string | null) => {
+      throw new Error(`process.exit(${code ?? 0})`);
+    }) as never);
+  });
+
+  afterEach(() => {
+    vi.restoreAllMocks();
+    vi.unstubAllEnvs();
+    Object.defineProperty(process.stdout, "isTTY", {
+      configurable: true,
+      value: originalStdoutIsTty,
+    });
+    delete process.env.NEMOCLAW_TEST_NO_SLEEP;
+    delete require.cache[requireDist.resolve(connectModulePath)];
+  });
+
+  it("prepares the NemoClaw Hermes light skin inside the sandbox on light macOS Terminal.app (#6380)", async () => {
+    vi.stubEnv("TERM_PROGRAM", "Apple_Terminal");
+    vi.stubEnv("COLORFGBG", "0;15");
+    vi.stubEnv("HERMES_TUI_LIGHT", "");
+    const harness = createConnectHarness({
+      agentName: "hermes",
+      sessionAgent: {
+        name: "hermes",
+        runtime: { kind: "terminal", interactive_command: "hermes" },
+      },
+    });
+
+    await expect(harness.connectSandbox("alpha")).rejects.toThrow("process.exit(0)");
+
+    expect(harness.captureOpenshellSpy).toHaveBeenCalledWith(
+      [
+        "sandbox",
+        "exec",
+        "--name",
+        "alpha",
+        "--",
+        "sh",
+        "-c",
+        'hermes_home="${HERMES_HOME:-/sandbox/.hermes}"; test -f "$hermes_home/config.yaml" && cat "$hermes_home/config.yaml" || true',
+      ],
+      expect.objectContaining({ ignoreError: true }),
+    );
+    const skinWriteCall = harness.runOpenshellSpy.mock.calls.find(
+      ([args]) =>
+        Array.isArray(args) &&
+        args.slice(0, 6).join(" ") === "sandbox exec --name alpha -- sh" &&
+        String(args[7] ?? "").includes("nemoclaw-light.yaml"),
+    );
+    expect(skinWriteCall?.[0][7]).toContain("/skins/nemoclaw-light.yaml");
+    expect(skinWriteCall?.[0][7]).toContain("config.yaml");
+
+    const connectCall = harness.spawnSyncSpy.mock.calls.find(
+      ([command, args]) =>
+        command === "openshell" &&
+        Array.isArray(args) &&
+        args.join(" ") === "sandbox connect alpha",
+    );
+    expect(connectCall?.[2]).toEqual(
+      expect.objectContaining({
+        env: expect.objectContaining({
+          COLORFGBG: "0;15",
+          TERM_PROGRAM: "Apple_Terminal",
+        }),
+      }),
+    );
+    expect(connectCall?.[2]?.env).not.toEqual(expect.objectContaining({ HERMES_TUI_LIGHT: "1" }));
+    expect(exitSpy).toHaveBeenCalledWith(0);
+  });
+
+  it("does not prepare the NemoClaw Hermes light skin when the sandbox Hermes config already sets display.skin (#6380)", async () => {
+    vi.stubEnv("TERM_PROGRAM", "Apple_Terminal");
+    vi.stubEnv("COLORFGBG", "0;15");
+    const harness = createConnectHarness({
+      agentName: "hermes",
+      sessionAgent: {
+        name: "hermes",
+        runtime: { kind: "terminal", interactive_command: "hermes" },
+      },
+    });
+    harness.captureOpenshellSpy.mockImplementation((args: unknown) => {
+      const argv = Array.isArray(args) ? args : [];
+      if (
+        argv[0] === "sandbox" &&
+        argv[1] === "exec" &&
+        argv.join(" ").includes("/sandbox/.hermes")
+      ) {
+        return { status: 0, output: "display:\n  skin: solarized-light\n" };
+      }
+      if (argv[0] === "sandbox" && argv[1] === "list") {
+        return { status: 0, output: "alpha Ready" };
+      }
+      if (argv[0] === "inference" && argv[1] === "get") {
+        return { status: 0, output: "Provider: unknown\nModel: unknown\n" };
+      }
+      return { status: 0, output: "" };
+    });
+
+    await expect(harness.connectSandbox("alpha")).rejects.toThrow("process.exit(0)");
+
+    const skinWriteCall = harness.runOpenshellSpy.mock.calls.find(
+      ([args]) =>
+        Array.isArray(args) &&
+        args.slice(0, 6).join(" ") === "sandbox exec --name alpha -- sh" &&
+        String(args[7] ?? "").includes("nemoclaw-light.yaml"),
+    );
+    expect(skinWriteCall).toBeUndefined();
+    expect(exitSpy).toHaveBeenCalledWith(0);
+  });
+});

src/lib/actions/sandbox/connect.ts

@@ -16,7 +16,15 @@ import {
 import * as agentRuntime from "../../agent/runtime";
 import { CLI_NAME } from "../../cli/branding";
 import { D, G, R, YW } from "../../cli/terminal-style";
+import { shellQuote } from "../../core/shell-quote";
 import { spawnExitCode } from "../../core/process-exit";
+import {
+  buildHermesLightSkinConfig,
+  buildSandboxConnectEnv,
+  hostTerminalLooksLight,
+  NEMOCLAW_HERMES_LIGHT_SKIN_YAML,
+  shouldPrepareHermesLightSkin,
+} from "../../domain/sandbox/connect-env";
 import { getNamedGatewayLifecycleState } from "../../gateway-runtime-action";
 import {
   parseGatewayInference,
@@ -81,6 +89,69 @@ type SpawnLikeResult = {
   signal?: NodeJS.Signals | null;
 };
 
+function encodeForSandboxWrite(content: string): string {
+  return Buffer.from(content, "utf8").toString("base64");
+}
+
+function readSandboxHermesConfig(sandboxName: string): string | null {
+  const result = captureOpenshell(
+    [
+      "sandbox",
+      "exec",
+      "--name",
+      sandboxName,
+      "--",
+      "sh",
+      "-c",
+      'hermes_home="${HERMES_HOME:-/sandbox/.hermes}"; test -f "$hermes_home/config.yaml" && cat "$hermes_home/config.yaml" || true',
+    ],
+    {
+      ignoreError: true,
+      timeout: OPENSHELL_PROBE_TIMEOUT_MS,
+      maxBuffer: 1024 * 1024,
+    },
+  );
+  if (result.status !== 0) return null;
+  return result.output ?? "";
+}
+
+function prepareHermesLightTerminalSkin(
+  sandboxName: string,
+  agent: { name?: string } | null | undefined,
+  env: NodeJS.ProcessEnv,
+): void {
+  if (
+    agent?.name !== "hermes" ||
+    !hostTerminalLooksLight(env) ||
+    String(env.HERMES_TUI_LIGHT ?? "").trim() ||
+    String(env.HERMES_TUI_THEME ?? "").trim()
+  ) {
+    return;
+  }
+
+  const currentConfig = readSandboxHermesConfig(sandboxName);
+  if (currentConfig === null || !shouldPrepareHermesLightSkin(agent, env, currentConfig)) return;
+
+  const updatedConfig = buildHermesLightSkinConfig(currentConfig);
+  if (!updatedConfig) return;
+
+  const skinB64 = encodeForSandboxWrite(NEMOCLAW_HERMES_LIGHT_SKIN_YAML);
+  const configB64 = encodeForSandboxWrite(updatedConfig);
+  const script = [
+    "set -eu",
+    'hermes_home="${HERMES_HOME:-/sandbox/.hermes}"',
+    'mkdir -p "$hermes_home/skins"',
+    `printf %s ${shellQuote(skinB64)} | base64 -d > "$hermes_home/skins/nemoclaw-light.yaml"`,
+    `printf %s ${shellQuote(configB64)} | base64 -d > "$hermes_home/config.yaml"`,
+  ].join("\n");
+
+  runOpenshell(["sandbox", "exec", "--name", sandboxName, "--", "sh", "-c", script], {
+    ignoreError: true,
+    stdio: "ignore",
+    timeout: OPENSHELL_PROBE_TIMEOUT_MS,
+  });
+}
+
 type SandboxListProbe = {
   status: number | null;
   output: string;
@@ -1089,10 +1160,11 @@ export async function connectSandbox(
     // OPENSHELL_SANDBOX) and covers every other interactive entry path too.
     console.log("");
   }
+  prepareHermesLightTerminalSkin(sandboxName, agent, process.env);
   const result = spawnSync(getOpenshellBinary(), ["sandbox", "connect", sandboxName], {
     stdio: "inherit",
     cwd: ROOT,
-    env: process.env,
+    env: buildSandboxConnectEnv(agent, process.env),
   });
   exitWithConnectSpawnResult(sandboxName, result);
 }

src/lib/domain/sandbox/connect-env.test.ts

@@ -0,0 +1,96 @@
+// SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+import { describe, expect, it } from "vitest";
+
+import {
+  buildHermesLightSkinConfig,
+  buildSandboxConnectEnv,
+  NEMOCLAW_HERMES_LIGHT_SKIN_NAME,
+  shouldPrepareHermesLightSkin,
+} from "./connect-env";
+
+describe("sandbox connect environment helpers", () => {
+  it("keeps the connect environment unchanged; Hermes light skin is prepared in sandbox config (#6380)", () => {
+    expect(
+      buildSandboxConnectEnv(
+        { name: "hermes" },
+        { COLORFGBG: "0;15", TERM_PROGRAM: "Apple_Terminal" },
+      ),
+    ).toEqual(
+      expect.objectContaining({
+        COLORFGBG: "0;15",
+        TERM_PROGRAM: "Apple_Terminal",
+      }),
+    );
+  });
+
+  it("plans the NemoClaw Hermes light skin only for light terminals without user theme or skin (#6380)", () => {
+    expect(
+      shouldPrepareHermesLightSkin(
+        { name: "hermes" },
+        { COLORFGBG: "0;15", TERM_PROGRAM: "Apple_Terminal" },
+        "model: test\n",
+      ),
+    ).toBe(true);
+  });
+
+  it("does not plan the NemoClaw Hermes light skin when the terminal is dark (#6380)", () => {
+    expect(
+      shouldPrepareHermesLightSkin(
+        { name: "hermes" },
+        { COLORFGBG: "0;0", TERM_PROGRAM: "Apple_Terminal" },
+        "model: test\n",
+      ),
+    ).toBe(false);
+  });
+
+  it("does not plan the NemoClaw Hermes light skin when the user set Hermes theme env (#6380)", () => {
+    for (const env of [{ HERMES_TUI_LIGHT: "0" }, { HERMES_TUI_THEME: "dark" }]) {
+      expect(
+        shouldPrepareHermesLightSkin({ name: "hermes" }, { COLORFGBG: "0;15", ...env }, ""),
+      ).toBe(false);
+    }
+  });
+
+  it("does not plan the NemoClaw Hermes light skin when config already has display.skin (#6380)", () => {
+    expect(
+      shouldPrepareHermesLightSkin(
+        { name: "hermes" },
+        { COLORFGBG: "0;15" },
+        "display:\n  skin: solarized-light\n",
+      ),
+    ).toBe(false);
+  });
+
+  it("does not plan the NemoClaw Hermes light skin for non-Hermes agents (#6380)", () => {
+    expect(
+      shouldPrepareHermesLightSkin({ name: "openclaw" }, { COLORFGBG: "0;15" }, "model: test\n"),
+    ).toBe(false);
+  });
+
+  it("does not infer light mode from Apple Terminal without usable COLORFGBG (#6380)", () => {
+    expect(
+      shouldPrepareHermesLightSkin({ name: "hermes" }, { TERM_PROGRAM: "Apple_Terminal" }, ""),
+    ).toBe(false);
+    expect(
+      shouldPrepareHermesLightSkin(
+        { name: "hermes" },
+        { COLORFGBG: "not-a-color", TERM_PROGRAM: "Apple_Terminal" },
+        "",
+      ),
+    ).toBe(false);
+  });
+
+  it("adds display.skin to Hermes config without changing existing fields (#6380)", () => {
+    expect(buildHermesLightSkinConfig("model: test\n")).toBe(
+      `model: test\ndisplay:\n  skin: ${NEMOCLAW_HERMES_LIGHT_SKIN_NAME}\n`,
+    );
+  });
+
+  it("does not rewrite Hermes config when display.skin is already explicit (#6380)", () => {
+    expect(
+      buildHermesLightSkinConfig("display:\n  skin: solarized-light\nmodel: test\n"),
+    ).toBeNull();
+  });
+});