diff --git a/api/Dockerfile b/api/Dockerfile
index dd726936..a1eeb33d 100644
--- a/api/Dockerfile
+++ b/api/Dockerfile
@@ -71,7 +71,7 @@ COPY --chown=appuser:appuser api/alembic/ ./alembic/
 COPY --chown=appuser:appuser api/scripts/run_migrations.py ./scripts/run_migrations.py
 COPY --chown=appuser:appuser packages/learn-to-cloud-shared/src/learn_to_cloud_shared/content/phases /app/content/phases
 
-ENV CONTENT_DIR="/app/content/phases"
+ENV CONTENT__DIR="/app/content/phases"
 
 CMD ["python", "scripts/run_migrations.py"]
 
diff --git a/api/scripts/run_migrations.py b/api/scripts/run_migrations.py
index 441c0d32..d6d278b2 100644
--- a/api/scripts/run_migrations.py
+++ b/api/scripts/run_migrations.py
@@ -23,7 +23,7 @@
 The sync CLI lives inside the installed package
 (``learn_to_cloud_shared.cli.sync_curriculum``) rather than a filesystem
 script. The migration image copies curriculum YAML separately and points
-``CONTENT_DIR`` at that path, so the API image does not need to ship YAML.
+``CONTENT__DIR`` at that path, so the API image does not need to ship YAML.
 ``python -m`` finds the module via the wheel's import path, which is
 portable across local devcontainer, CI, and production.
 """
diff --git a/packages/learn-to-cloud-shared/src/learn_to_cloud_shared/cli/sync_curriculum.py b/packages/learn-to-cloud-shared/src/learn_to_cloud_shared/cli/sync_curriculum.py
index c99a9003..b8b8818e 100644
--- a/packages/learn-to-cloud-shared/src/learn_to_cloud_shared/cli/sync_curriculum.py
+++ b/packages/learn-to-cloud-shared/src/learn_to_cloud_shared/cli/sync_curriculum.py
@@ -3,7 +3,7 @@
 Importable CLI entry point for the deploy-time curriculum sync.
 
 Usage (anywhere the ``learn-to-cloud-shared`` wheel is installed and
-``CONTENT_DIR`` points at ``content/phases``)::
+``CONTENT__DIR`` points at ``content/phases``)::
 
     python -m learn_to_cloud_shared.cli.sync_curriculum
 
diff --git a/packages/learn-to-cloud-shared/src/learn_to_cloud_shared/content_sync.py b/packages/learn-to-cloud-shared/src/learn_to_cloud_shared/content_sync.py
index 727807b1..bcb0b7bc 100644
--- a/packages/learn-to-cloud-shared/src/learn_to_cloud_shared/content_sync.py
+++ b/packages/learn-to-cloud-shared/src/learn_to_cloud_shared/content_sync.py
@@ -1,6 +1,6 @@
 """Deploy-time sync from YAML curriculum to DB tables (issue #463).
 
-Reads the authored curriculum YAML from ``CONTENT_DIR`` in production,
+Reads the authored curriculum YAML from ``CONTENT__DIR`` in production,
 runs the strict cross-file validators, and upserts every curriculum entity
 into its corresponding DB table. Entities no longer present in YAML are
 soft-deleted; entities that reappear (same UUID) have their ``deleted_at``
diff --git a/packages/learn-to-cloud-shared/src/learn_to_cloud_shared/content_yaml_loader.py b/packages/learn-to-cloud-shared/src/learn_to_cloud_shared/content_yaml_loader.py
index f220135e..9595bfdb 100644
--- a/packages/learn-to-cloud-shared/src/learn_to_cloud_shared/content_yaml_loader.py
+++ b/packages/learn-to-cloud-shared/src/learn_to_cloud_shared/content_yaml_loader.py
@@ -5,7 +5,7 @@
 ``content_db_loader.py`` via the public ``content_service`` module. The YAML
 loader is still authoritative for deploy-time YAML to DB sync
 (``content_sync.py``) and for the strict cross-file validators run in CI.
-Production migration jobs provide the YAML path through ``CONTENT_DIR``.
+Production migration jobs provide the YAML path through ``CONTENT__DIR``.
 
 Do not import from this module in request-serving code paths. Use
 ``learn_to_cloud_shared.content_service`` (async, DB-backed) instead.