fix(cli): stop leaking API keys to CLI app subprocesses

Installed CLI apps were started with os.environ.copy(), so provider keys
from the parent process were visible to untrusted binaries. Use a minimal
allowlist env matching the shell tool.

Fixes #4783

nanobot/apps/cli/service.py

@@ -990,6 +990,35 @@ class CliAppManager:
             return None
         raise CliAppError("this CLI app uses an unsupported install strategy")
 
+    def _subprocess_env(self) -> dict[str, str]:
+        """Minimal env for CLI app subprocesses — no API keys or secrets.
+
+        Mirrors the shell tool's allowlist so installed apps cannot read
+        provider credentials from the parent process environment.
+        """
+        if sys.platform == "win32":
+            sr = os.environ.get("SYSTEMROOT", r"C:\Windows")
+            env = {
+                "SYSTEMROOT": sr,
+                "COMSPEC": os.environ.get("COMSPEC", f"{sr}\\system32\\cmd.exe"),
+                "USERPROFILE": os.environ.get("USERPROFILE", ""),
+                "HOMEDRIVE": os.environ.get("HOMEDRIVE", "C:"),
+                "HOMEPATH": os.environ.get("HOMEPATH", "\\"),
+                "TEMP": os.environ.get("TEMP", f"{sr}\\Temp"),
+                "TMP": os.environ.get("TMP", f"{sr}\\Temp"),
+                "PATHEXT": os.environ.get("PATHEXT", ".COM;.EXE;.BAT;.CMD"),
+                "PATH": os.environ.get("PATH", f"{sr}\\system32;{sr}"),
+                "PYTHONUNBUFFERED": "1",
+            }
+            return {k: v for k, v in env.items() if v is not None}
+        return {
+            "HOME": os.environ.get("HOME", "/tmp"),
+            "LANG": os.environ.get("LANG", "C.UTF-8"),
+            "TERM": os.environ.get("TERM", "dumb"),
+            "PATH": os.environ.get("PATH", "/usr/bin:/bin"),
+            "PYTHONUNBUFFERED": "1",
+        }
+
         def _run_argv(self, argv: list[str], *, timeout: int) -> subprocess.CompletedProcess[str]:
         command = subprocess.list2cmdline(argv)
         logger.info("CLI Apps: running {}", command)
@@ -1431,7 +1460,7 @@ Use the `run_cli_app` tool with `name="{name}"` for command execution. Do not in
                 encoding="utf-8",
                 errors="replace",
                 timeout=effective_timeout,
-                env=os.environ.copy(),
+                env=self._subprocess_env(),
             )
         except subprocess.TimeoutExpired:
             return f"CLI app '{name}' timed out after {effective_timeout}s"

tests/apps/test_cli_subprocess_env.py

@@ -0,0 +1,54 @@
+"""CLI app subprocesses must not inherit API keys from the parent environ."""
+
+from __future__ import annotations
+
+from nanobot.apps.cli.service import CliAppManager
+
+
+def test_subprocess_env_excludes_api_keys(monkeypatch, tmp_path) -> None:
+    monkeypatch.setenv("OPENAI_API_KEY", "sk-should-not-leak")
+    monkeypatch.setenv("ANTHROPIC_API_KEY", "sk-ant-leak")
+    monkeypatch.setenv("OPENROUTER_API_KEY", "sk-or-leak")
+
+    manager = CliAppManager(workspace=tmp_path, data_dir=tmp_path / "cli-apps")
+    env = manager._subprocess_env()
+
+    assert "OPENAI_API_KEY" not in env
+    assert "ANTHROPIC_API_KEY" not in env
+    assert "OPENROUTER_API_KEY" not in env
+    assert env.get("PYTHONUNBUFFERED") == "1"
+    assert "PATH" in env
+
+
+def test_run_passes_filtered_env(monkeypatch, tmp_path) -> None:
+    monkeypatch.setenv("OPENAI_API_KEY", "sk-should-not-leak")
+    manager = CliAppManager(workspace=tmp_path, data_dir=tmp_path / "cli-apps")
+    captured: dict[str, object] = {}
+
+    def fake_run(*args, **kwargs):
+        captured.update(kwargs)
+
+        class Result:
+            returncode = 0
+            stdout = "ok"
+            stderr = ""
+
+        return Result()
+
+    monkeypatch.setattr("nanobot.apps.cli.service.subprocess.run", fake_run)
+    monkeypatch.setattr(manager, "get_app", lambda name: {"name": name, "entry_point": "echo"})
+    monkeypatch.setattr(
+        manager,
+        "_load_installed",
+        lambda: {"echo": {"entry_point": "echo"}},
+    )
+    monkeypatch.setattr("nanobot.apps.cli.service.shutil.which", lambda entry: "/bin/echo")
+    monkeypatch.setattr(manager, "_resolve_cwd", lambda *a, **k: tmp_path)
+    monkeypatch.setattr(manager, "_artifact_snapshot", lambda cwd: {})
+    monkeypatch.setattr(manager, "_changed_artifacts", lambda cwd, snap: [])
+
+    manager.run("echo", ["hi"])
+
+    env = captured.get("env")
+    assert isinstance(env, dict)
+    assert "OPENAI_API_KEY" not in env