diff --git a/CLAUDE.md b/CLAUDE.md
index a13836c..8b6fbb2 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -25,7 +25,7 @@ Everything lives in the single root `Dockerfile`. Its layer order mirrors the ol
 - Modeling stack from the CURRENT P3M snapshot: `tidymodels`, `bonsai`, engines (`xgboost`, `lightgbm`, `randomForest`, `ranger`, `glmnet`), `catboost` (pinned GitHub release binary, amd64), `brms` (+ explicit `BH`/`RcppEigen`/`RcppParallel` — rstan binary installs skip its LinkingTo deps, but runtime Stan compilation needs them).
 - Inference-reporting + presentation set: `gt`, `marginaleffects`, `patchwork`, `easystats` — used pervasively in the primer book and tutorials but only Suggests in primer.tutorials (pak doesn't install Suggests).
 - Package-development set (the old dev image): `devtools`, `pkgdown`, `roxygen2`, `testthat`, `usethis`.
-- Course packages from GitHub source (`PPBDS/tutorial.helpers`, `PPBDS/vscode.tutorials`, `PPBDS/misc.tutorials`, `PPBDS/primer/primer.tutorials` — note the subdir path), installed **as rstudio** with `upgrade = TRUE` (see the xfun ABI note in the Dockerfile). These are ALSO refreshed on every Codespace create by codespace-starter's postCreateCommand — add new course packages in BOTH places.
+- Course packages from GitHub source (`PPBDS/tutorial.helpers`, `PPBDS/vscode.tutorials`, `PPBDS/misc.tutorials`, `PPBDS/primer.tutorials` — split out of the primer repo 2026-07 so installs stop downloading the 183 MB primer tarball; don't point it back at the subdir), installed **as rstudio** with `upgrade = TRUE` (see the xfun ABI note in the Dockerfile). These are ALSO refreshed on every Codespace create by codespace-starter's postCreateCommand — add new course packages in BOTH places.
 - Interactive viz + Shinylive (R: `plotly`, `leaflet`, `DT`, `crosstalk`, `shiny`, `shinylive`).
 - Mapping/census stack: `sf`, `tidycensus` (+`tigris`), `mapgl` (token-free WebGL maps via `maplibre()` + CARTO styles), `crsuggest`, `idbr`. Live tidycensus/idbr queries need each student's free Census API key (the API rejects keyless requests). `mapboxapi` deliberately excluded (needs per-student Mapbox account).
 - Python data-science stack via `uv` into a group-writable venv at `/opt/venv` from a fully pinned lockfile (`requirements.lock`, compiled from `requirements.txt` — edit the .txt and recompile to bump). System CPython, seeded pip, default `python` on PATH, registered "Python (data science)" Jupyter kernel; Quarto runs Python docs via the jupyter engine, so reticulate is not needed (RETICULATE_PYTHON is still set).
diff --git a/Dockerfile b/Dockerfile
index 5a5db9a..aea68d1 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -298,8 +298,11 @@ RUN R -q -e 'pak::pkg_install(c("devtools", "pkgdown", "roxygen2", "testthat", "
 # create via codespace-starter's postCreateCommand; baking them here pre-
 # installs the whole dependency tree (so that refresh is a quick update, not
 # a cold build) and leaves a working fallback if GitHub is unreachable. Note
-# primer.tutorials lives in a SUBDIR of the primer repo, hence the
-# "PPBDS/primer/primer.tutorials" path. Add further "PPBDS/<name>" entries
+# primer.tutorials was SPLIT OUT of the primer repo (2026-07): as a subdir
+# install ("PPBDS/primer/primer.tutorials") every install downloaded the
+# full ~183 MB primer tarball — book, class exercises — to deliver a ~4 MB
+# package, at every image build AND every Codespace create. Do not point
+# this back at the subdir path. Add further "PPBDS/<name>" entries
 # (in BOTH places) when the syllabus needs them.
 #
 # upgrade = TRUE forces pak to pull the latest version of every
@@ -311,7 +314,7 @@ RUN R -q -e 'pak::pkg_install(c( \
         "PPBDS/tutorial.helpers", \
         "PPBDS/vscode.tutorials", \
         "PPBDS/misc.tutorials", \
-        "PPBDS/primer/primer.tutorials" \
+        "PPBDS/primer.tutorials" \
     ), upgrade = TRUE)'
 
 # Smoke test 1: every baked-in package and the learnr/knitr/rmarkdown