diff --git a/sidecar/attune_gui/home_summary.py b/sidecar/attune_gui/home_summary.py
index cedd93c..2eed64f 100644
--- a/sidecar/attune_gui/home_summary.py
+++ b/sidecar/attune_gui/home_summary.py
@@ -84,6 +84,8 @@ class HomeSummary:
     sparkline_points: str = ""  # SVG polyline points string ("" = no data)
     recent_jobs: list[RecentJob] = field(default_factory=list)
     family: list[FamilyVersion] = field(default_factory=list)
+    family_interpreter: str | None = None  # sys.executable of dashboard process
+    family_python_version: str | None = None  # e.g. "3.11.7"
     workspace_path: str | None = None
     manifest_path: str | None = None
     feature_count: int = 0
@@ -236,9 +238,13 @@ async def build_home_summary() -> HomeSummary:
         logger.debug("home: cowork_templates.list_templates failed; using empty list")
 
     layers: dict[str, dict[str, Any]] = {}
+    interpreter: str | None = None
+    python_version: str | None = None
     try:
         layer_data = await cowork_health.layer_health()
         layers = layer_data.get("layers", {})
+        interpreter = layer_data.get("interpreter")
+        python_version = layer_data.get("python_version")
     except Exception:  # noqa: BLE001
         logger.debug("home: cowork_health.layer_health failed; using empty list")
 
@@ -277,6 +283,8 @@ async def build_home_summary() -> HomeSummary:
         sparkline_points=points,
         recent_jobs=recent,
         family=family,
+        family_interpreter=interpreter,
+        family_python_version=python_version,
         workspace_path=workspace_path,
         manifest_path=manifest_path,
         feature_count=feature_count,
diff --git a/sidecar/attune_gui/routes/cowork_health.py b/sidecar/attune_gui/routes/cowork_health.py
index 42161db..6ddbb7c 100644
--- a/sidecar/attune_gui/routes/cowork_health.py
+++ b/sidecar/attune_gui/routes/cowork_health.py
@@ -10,6 +10,7 @@
 from __future__ import annotations
 
 import importlib.metadata as ilm
+import sys
 from typing import Any
 
 from fastapi import APIRouter
@@ -35,8 +36,19 @@ def _probe(pkg: str) -> dict[str, Any]:
 
 @router.get("/layers")
 async def layer_health() -> dict[str, Any]:
-    """Return version + importability for each attune layer."""
-    return {"layers": {key: _probe(pkg) for key, pkg in _PACKAGES}}
+    """Return version + importability for each attune layer.
+
+    Also surfaces the interpreter probing for metadata — a "not installed"
+    result is usually an env-mismatch (dashboard running under a different
+    Python than the venv that has the package), so the interpreter path
+    makes the situation self-diagnosing.
+    """
+    vi = sys.version_info
+    return {
+        "layers": {key: _probe(pkg) for key, pkg in _PACKAGES},
+        "interpreter": sys.executable,
+        "python_version": f"{vi.major}.{vi.minor}.{vi.micro}",
+    }
 
 
 @router.get("/corpus")
diff --git a/sidecar/attune_gui/templates/home.html b/sidecar/attune_gui/templates/home.html
index 57b2677..e7009ce 100644
--- a/sidecar/attune_gui/templates/home.html
+++ b/sidecar/attune_gui/templates/home.html
@@ -123,6 +123,13 @@ <h2 class="section-title">Workspace</h2>
 
   <section class="section">
     <h2 class="section-title">Family snapshot</h2>
+    {% if summary.family_interpreter %}
+      <p class="meta-line">
+        Probed under
+        <code title="Dashboard process interpreter. A 'Not installed' result usually means this Python differs from the venv where the package lives.">{{ summary.family_interpreter }}</code>
+        {% if summary.family_python_version %}(Python {{ summary.family_python_version }}){% endif %}
+      </p>
+    {% endif %}
     <div class="grid grid-4">
       {% for v in summary.family %}
         <article class="card layer-card {% if v.importable %}ok{% else %}danger{% endif %}">
diff --git a/sidecar/tests/test_cowork_health.py b/sidecar/tests/test_cowork_health.py
index 2ccc4d3..5bd03b9 100644
--- a/sidecar/tests/test_cowork_health.py
+++ b/sidecar/tests/test_cowork_health.py
@@ -26,6 +26,18 @@ def test_layers_returns_all_known_packages(client: TestClient) -> None:
         assert "version" in info
 
 
+def test_layers_includes_interpreter_diagnostic(client: TestClient) -> None:
+    """A 'not installed' result is usually env-mismatch; the response surfaces
+    the interpreter so the dashboard is self-diagnosing."""
+    r = client.get("/api/cowork/layers", headers={"Origin": "http://localhost:5173"})
+    assert r.status_code == 200
+    body = r.json()
+    assert isinstance(body["interpreter"], str) and body["interpreter"]
+    assert isinstance(body["python_version"], str)
+    # "3.11.7" style
+    assert body["python_version"].count(".") == 2
+
+
 def test_layers_handles_missing_package(
     client: TestClient, monkeypatch: pytest.MonkeyPatch
 ) -> None:
diff --git a/sidecar/tests/test_home_summary.py b/sidecar/tests/test_home_summary.py
index 2f6cc3f..9d55aba 100644
--- a/sidecar/tests/test_home_summary.py
+++ b/sidecar/tests/test_home_summary.py
@@ -209,7 +209,13 @@ async def test_build_home_summary_composes_all_sources():
             "templates_root": "/fake/help",
         }
     )
-    fake_layers = AsyncMock(return_value={"layers": {"ai": {"importable": True, "version": "9"}}})
+    fake_layers = AsyncMock(
+        return_value={
+            "layers": {"ai": {"importable": True, "version": "9"}},
+            "interpreter": "/fake/.venv/bin/python",
+            "python_version": "3.11.7",
+        }
+    )
     fake_corpus = AsyncMock(
         return_value={"manifest_path": "/fake/help/features.yaml", "feature_count": 4}
     )
@@ -241,6 +247,8 @@ async def test_build_home_summary_composes_all_sources():
     assert summary.manifest_path == "/fake/help/features.yaml"
     assert len(summary.family) == 1
     assert summary.family[0].package == "attune-ai"
+    assert summary.family_interpreter == "/fake/.venv/bin/python"
+    assert summary.family_python_version == "3.11.7"
     assert len(summary.recent_jobs) == 1
     assert summary.recent_jobs[0].name == "demo.run"
     assert len(summary.sparkline) == 7