diff --git a/src/anthias_server/api/tests/test_info_endpoints.py b/src/anthias_server/api/tests/test_info_endpoints.py
index fa6c0140..715466ae 100644
--- a/src/anthias_server/api/tests/test_info_endpoints.py
+++ b/src/anthias_server/api/tests/test_info_endpoints.py
@@ -2,7 +2,6 @@
 Tests for Info API endpoints (v1 and v2).
 """
 
-from importlib.metadata import version as _pkg_version
 from typing import Any
 from unittest import mock
 
@@ -11,10 +10,14 @@ from django.urls import reverse
 from rest_framework import status
 from rest_framework.test import APIClient
 
-# Pulled from pyproject.toml's [project].version via the installed
-# package metadata so the test moves in lockstep with the release
-# bumper without anyone having to update both places.
-_ANTHIAS_RELEASE = _pkg_version('anthias')
+from anthias_server.lib.diagnostics import get_anthias_release
+
+# Pulled from pyproject.toml's [project].version via the diagnostics
+# helper so the test moves in lockstep with the release bumper, and
+# also works in environments built with `uv sync --no-install-project`
+# (production, host install) where importlib.metadata wouldn't find
+# the package — the helper falls back to a tomllib read.
+_ANTHIAS_RELEASE = get_anthias_release()
 
 
 @pytest.fixture
diff --git a/src/anthias_server/lib/diagnostics.py b/src/anthias_server/lib/diagnostics.py
index c5a43b72..9be2d9ac 100755
--- a/src/anthias_server/lib/diagnostics.py
+++ b/src/anthias_server/lib/diagnostics.py
@@ -92,17 +92,57 @@ _RELEASE_BRANCHES = frozenset({'master', 'main'})
 
 
 def get_anthias_release() -> str:
-    """Read the project version from the installed package metadata
-    (sourced from pyproject.toml's [project].version, currently
-    CalVer ``YYYY.M.MICRO``). Falls back to the empty string when the
-    package isn't installed under this interpreter — e.g. running
-    ad-hoc scripts straight off the source tree without `uv sync`."""
+    """Read the project version, sourced from pyproject.toml's
+    [project].version (currently CalVer ``YYYY.M.MICRO``).
+
+    Resolution order:
+      1. ``importlib.metadata.version('anthias')`` — works for
+         editable installs (``pip install -e .``) and any path where
+         the project ships as a wheel.
+      2. Fallback: parse ``pyproject.toml`` directly with ``tomllib``.
+         Required because every production / test / host environment
+         runs ``uv sync --no-install-project`` (see
+         docker/uv-builder.j2, docker/Dockerfile.{server,test,viewer},
+         bin/install.sh) — that flag installs the project's deps but
+         NOT the project itself, so importlib.metadata has no record
+         of an ``anthias`` distribution to read.
+
+    Cached after first successful read so the System Info HTML render
+    (called per request) and the v2 info API don't re-open the file.
+    Returns the empty string only when both sources fail.
+    """
+    cached: str | None = getattr(get_anthias_release, '_cached', None)
+    if cached is not None:
+        return cached
+    value: str
     try:
         from importlib.metadata import PackageNotFoundError, version
 
-        return version('anthias')
-    except PackageNotFoundError:
-        return ''
+        try:
+            value = version('anthias')
+        except PackageNotFoundError:
+            value = _read_version_from_pyproject()
+    except Exception:
+        value = ''
+    setattr(get_anthias_release, '_cached', value)
+    return value
+
+
+def _read_version_from_pyproject() -> str:
+    """Last-ditch source for the project version when the package
+    isn't installed in the active venv. Walks up from this file to
+    find the repo-root pyproject.toml — `__file__` lives at
+    ``src/anthias_server/lib/diagnostics.py``, so parents[3] is the
+    checkout root in both editable installs and the
+    ``uv sync --no-install-project`` Docker layout."""
+    try:
+        import tomllib
+        from pathlib import Path
+
+        pyproject = Path(__file__).resolve().parents[3] / 'pyproject.toml'
+        with pyproject.open('rb') as f:
+            data = tomllib.load(f)
+        return str(data.get('project', {}).get('version', ''))
     except Exception:
         return ''