diff --git a/script/poetry/poetry_add_build_dependency.sh b/script/poetry/poetry_add_build_dependency.sh
index 3aedc13..be32cd4 100755
--- a/script/poetry/poetry_add_build_dependency.sh
+++ b/script/poetry/poetry_add_build_dependency.sh
@@ -22,6 +22,10 @@ if [[ ${#DEPS[@]} -eq 0 ]]; then
     exit 0
 fi
 
+# poetry travaille dans le venv actif s'il y en a un : sans cette activation,
+# un shell sous .venv.erplibre lui imposerait un Python hors des bornes du
+# pyproject (InvalidCurrentPythonVersionError).
+source "${VENV}/bin/activate"
 "${VENV}/bin/poetry" add -vv "${DEPS[@]}"
 retVal=$?
 if [[ $retVal -ne 0 ]]; then
diff --git a/script/poetry/poetry_update.py b/script/poetry/poetry_update.py
index 5b20823..7354531 100755
--- a/script/poetry/poetry_update.py
+++ b/script/poetry/poetry_update.py
@@ -8,6 +8,7 @@ import logging
 import os
 import re
 import shutil
+import subprocess
 import sys
 from collections import OrderedDict, defaultdict
 from pathlib import Path
@@ -627,9 +628,14 @@ def call_poetry_lock(config):
     """
     :return: True if success
     """
-    venv_dir = f".venv.{config.set_version_erplibre}"
-    status = os.system(f"./{venv_dir}/bin/poetry lock")
-    return status == 0
+    venv_dir = os.path.abspath(f".venv.{config.set_version_erplibre}")
+    # poetry works in the active venv when there is one: the caller's
+    # VIRTUAL_ENV (often .venv.erplibre) would hand it a Python outside the
+    # pyproject bounds, so the Odoo venv is activated for this call.
+    env = dict(os.environ, VIRTUAL_ENV=venv_dir)
+    env["PATH"] = os.pathsep.join([f"{venv_dir}/bin", env.get("PATH", "")])
+    status = subprocess.run([f"{venv_dir}/bin/poetry", "lock"], env=env)
+    return status.returncode == 0
 
 
 def call_poetry_add_build_dependency():