diff --git a/routes/shell_routes.py b/routes/shell_routes.py
index 3fec36f..fa8177b 100644
--- a/routes/shell_routes.py
+++ b/routes/shell_routes.py
@@ -9,6 +9,7 @@ import shutil
 import subprocess
 import uuid
 import tempfile
+from collections import namedtuple
 from pathlib import Path
 from typing import Dict, Any
 
@@ -61,6 +62,36 @@ logger = logging.getLogger(__name__)
 PTY_SUPPORTED = pty is not None and fcntl is not None and hasattr(os, "setsid")
 
 
+DOCKER_IN_CONTAINER_HINT = (
+    "Not available inside the Odysseus container by design. The image ships no "
+    "docker CLI and no host socket is mounted. Run Docker-backed launches on a "
+    "remote server, where docker is checked over SSH. Mounting /var/run/docker.sock "
+    "into the container would grant it host-root access, so only do that if you "
+    "accept that risk."
+)
+
+
+def _running_in_container(dockerenv_path="/.dockerenv", cgroup_path="/proc/1/cgroup"):
+    if os.path.exists(dockerenv_path):
+        return True
+    try:
+        with open(cgroup_path, "r", encoding="utf-8") as fh:
+            contents = fh.read()
+    except OSError:
+        return False
+    return any(token in contents for token in ("docker", "containerd", "kubepods"))
+
+
+DockerRowStatus = namedtuple("DockerRowStatus", ["applicable", "install_hint"])
+
+
+def _docker_row_status(*, on_remote, in_container, installed, default_hint):
+    local_docker_unavailable = not on_remote and in_container and not installed
+    if local_docker_unavailable:
+        return DockerRowStatus(applicable=False, install_hint=DOCKER_IN_CONTAINER_HINT)
+    return DockerRowStatus(applicable=True, install_hint=default_hint)
+
+
 def _find_line_break(buf):
     """Find next line terminator in buffer. Returns (index, separator_length) or (-1, 0)."""
     ni = buf.find(b"\n")
@@ -702,20 +733,29 @@ def setup_shell_routes() -> APIRouter:
                 pass
 
         for pkg in packages:
-            if host and pkg.get("target") == "remote":
+            on_remote = bool(host and pkg.get("target") == "remote")
+            if on_remote:
                 pkg["installed"] = bool(remote_status.get(pkg["name"], False))
-                continue
-            if pkg.get("kind") == "system":
+            elif pkg.get("kind") == "system":
                 pkg["installed"] = shutil.which(pkg["name"]) is not None
-                continue
-            try:
-                if pkg["name"] == "llama_cpp" and shutil.which("llama-server"):
-                    pkg["installed"] = True
-                    continue
-                importlib.import_module(pkg["name"])
+            elif pkg["name"] == "llama_cpp" and shutil.which("llama-server"):
                 pkg["installed"] = True
-            except ImportError:
-                pkg["installed"] = False
+            else:
+                try:
+                    importlib.import_module(pkg["name"])
+                    pkg["installed"] = True
+                except ImportError:
+                    pkg["installed"] = False
+
+            if pkg["name"] == "docker":
+                status = _docker_row_status(
+                    on_remote=on_remote,
+                    in_container=_running_in_container() if not on_remote else False,
+                    installed=pkg["installed"],
+                    default_hint=pkg.get("install_hint"),
+                )
+                pkg["applicable"] = status.applicable
+                pkg["install_hint"] = status.install_hint
         return {"packages": packages}
 
     @router.post("/api/cookbook/packages/install")
diff --git a/static/js/cookbook.js b/static/js/cookbook.js
index 795bcf2..1fd172c 100644
--- a/static/js/cookbook.js
+++ b/static/js/cookbook.js
@@ -542,7 +542,11 @@ async function _fetchDependencies() {
       if (winBlocked) return `<span class="cookbook-dep-tag cookbook-dep-na">N/A</span>`;
       if (pkg.installed && isSystemDep) return `<span class="cookbook-dep-tag cookbook-dep-installed" title="Found on selected server">Installed</span>`;
       if (pkg.installed) return `<button class="cookbook-dep-tag cookbook-dep-installed cookbook-dep-installed-btn" title="Installed — click for actions"><span class="cookbook-dep-installed-label">Installed</span><span class="cookbook-dep-caret">&#9662;</span></button>`;
-      if (isSystemDep) return `<span class="cookbook-dep-tag cookbook-dep-na" title="${esc(pkg.install_hint || 'Install this OS package on the selected server.')}">Missing</span>`;
+      if (isSystemDep) {
+        const depTip = esc(pkg.install_hint || 'Install this OS package on the selected server.');
+        const depLabel = pkg.applicable === false ? 'N/A ?' : 'Missing';
+        return `<span class="cookbook-dep-tag cookbook-dep-na" title="${depTip}">${depLabel}</span>`;
+      }
       return `<button class="cookbook-dep-tag cookbook-dep-install" data-dep-pip="${esc(pkg.pip)}" data-dep-target="${isLocal ? 'local' : 'remote'}">Install</button>`;
     };
 
diff --git a/static/style.css b/static/style.css
index c7907b3..5da0a7e 100644
--- a/static/style.css
+++ b/static/style.css
@@ -18153,7 +18153,10 @@ body.gallery-selecting .gallery-dl-btn,
   border: 1px solid color-mix(in srgb, var(--green, #50fa7b) 35%, transparent);
 }
 .cookbook-dep-na {
-  color: color-mix(in srgb, var(--fg) 35%, transparent);
+  background: color-mix(in srgb, var(--fg) 8%, transparent);
+  color: color-mix(in srgb, var(--fg) 60%, transparent);
+  border: 1px solid color-mix(in srgb, var(--fg) 16%, transparent);
+  cursor: help;
 }
 .cookbook-dep-install {
   background: var(--accent, var(--red));
diff --git a/tests/test_shell_routes.py b/tests/test_shell_routes.py
index 4833ef3..dbe932e 100644
--- a/tests/test_shell_routes.py
+++ b/tests/test_shell_routes.py
@@ -7,7 +7,12 @@ import sys
 from pathlib import Path
 from types import SimpleNamespace
 
-from routes.shell_routes import _find_line_break
+from routes.shell_routes import (
+    _find_line_break,
+    _running_in_container,
+    _docker_row_status,
+    DOCKER_IN_CONTAINER_HINT,
+)
 
 
 def test_shell_routes_import_without_posix_pty_modules(monkeypatch):
@@ -99,3 +104,81 @@ class TestFindLineBreak:
     def test_newline_before_cr(self):
         """\\n comes before \\r — should return \\n."""
         assert _find_line_break(b"ab\ncd\r") == (2, 1)
+
+
+class TestRunningInContainer:
+    """Detect whether the Odysseus process itself runs inside a container."""
+
+    def test_dockerenv_marker_present(self, tmp_path):
+        marker = tmp_path / ".dockerenv"
+        marker.write_text("")
+        assert _running_in_container(
+            dockerenv_path=str(marker), cgroup_path=str(tmp_path / "missing"),
+        ) is True
+
+    def test_cgroup_names_a_container_runtime(self, tmp_path):
+        cgroup = tmp_path / "cgroup"
+        cgroup.write_text("12:devices:/docker/abcdef0123456789\n")
+        assert _running_in_container(
+            dockerenv_path=str(tmp_path / "no-marker"), cgroup_path=str(cgroup),
+        ) is True
+
+    def test_bare_host_has_neither_signal(self, tmp_path):
+        cgroup = tmp_path / "cgroup"
+        cgroup.write_text("0::/user.slice/session-1.scope\n")
+        assert _running_in_container(
+            dockerenv_path=str(tmp_path / "no-marker"), cgroup_path=str(cgroup),
+        ) is False
+
+    def test_missing_cgroup_file_is_not_a_container(self, tmp_path):
+        assert _running_in_container(
+            dockerenv_path=str(tmp_path / "no-marker"),
+            cgroup_path=str(tmp_path / "also-missing"),
+        ) is False
+
+
+class TestDockerRowStatus:
+    """Applicability plus install hint for the docker dependency row."""
+
+    DEFAULT = "Install Docker on the selected server."
+
+    def test_in_container_and_absent_is_not_applicable_with_safe_default_hint(self):
+        status = _docker_row_status(
+            on_remote=False, in_container=True, installed=False, default_hint=self.DEFAULT,
+        )
+        assert status.applicable is False
+        assert status.install_hint == DOCKER_IN_CONTAINER_HINT
+
+    def test_in_container_but_present_is_applicable_with_default_hint(self):
+        status = _docker_row_status(
+            on_remote=False, in_container=True, installed=True, default_hint=self.DEFAULT,
+        )
+        assert status.applicable is True
+        assert status.install_hint == self.DEFAULT
+
+    def test_on_host_and_absent_stays_applicable_with_default_hint(self):
+        status = _docker_row_status(
+            on_remote=False, in_container=False, installed=False, default_hint=self.DEFAULT,
+        )
+        assert status.applicable is True
+        assert status.install_hint == self.DEFAULT
+
+    def test_remote_server_is_always_applicable_even_when_absent(self):
+        status = _docker_row_status(
+            on_remote=True, in_container=False, installed=False, default_hint=self.DEFAULT,
+        )
+        assert status.applicable is True
+        assert status.install_hint == self.DEFAULT
+
+    def test_remote_server_ignores_local_container_status(self):
+        status = _docker_row_status(
+            on_remote=True, in_container=True, installed=False, default_hint=self.DEFAULT,
+        )
+        assert status.applicable is True
+        assert status.install_hint == self.DEFAULT
+
+    def test_container_hint_steers_to_remote_and_warns_on_socket(self):
+        lowered = DOCKER_IN_CONTAINER_HINT.lower()
+        assert "remote" in lowered
+        assert "socket" in lowered
+        assert "host-root" in lowered or "host root" in lowered