diff --git a/build-helpers/full-init b/build-helpers/full-init
index 46e85d4..eae7e02 100755
--- a/build-helpers/full-init
+++ b/build-helpers/full-init
@@ -15,9 +15,21 @@
 ;; See the License for the specific language governing permissions and
 ;; limitations under the License.
 
+;; Simple recursive walk of packages.el to extract (modulep! +flag)
+;;
+;; Does not cover (modulep! :cat mod +flag). That is: assumes each flag is
+;; referenced at least once by shortened form in the module itself.
+;;
+;; No attempt at efficiency, but package.el files are small...
+
+(defun walk-package-exp (l)
+  (cond ((not (consp l)) nil)
+        ((and (= 2 (length l)) (eq 'modulep! (car l))) (cdr l))
+        (t (mapcan #'walk-package-exp l))))
+
 (defcli! full-init
     ((output-directory ("-o" dir) "Directory to write init.el into.")
-     (&flag full? ("--full")))
+     (&flag flags? ("--flags")))
   "Write init.el with all modules."
   (with-temp-buffer
     (insert ";;; init.el -*- no-byte-compile: t; -*-
@@ -30,8 +42,18 @@
       (let ((cat (car kp))
             (name (cdr kp)))
         (when name
-          (if full?
-              (error "unimplemented")
+          (if-let ((flags?)
+                   (packages-path (doom-module-locate-path
+                                   cat name doom-module-packages-file))
+                   (tree (with-temp-buffer
+                           (insert "(\n")
+                           (insert-file-contents packages-path)
+                           (goto-char (point-max))
+                           (insert ")\n")
+                           (goto-char (point-min))
+                           (read (current-buffer))))
+                   (flags (walk-package-exp tree)))
+              (insert (format " %s %s\n" cat (cons name flags)))
             (insert (format " %s %s\n" cat name))))))
     (insert ")\n")
     (write-region nil nil (expand-file-name "init.el" output-directory))))
diff --git a/checks.nix b/checks.nix
index 6e680f8..07d6d0c 100644
--- a/checks.nix
+++ b/checks.nix
@@ -37,7 +37,8 @@ let
   mkDoom = args: (makeDoomPackages (common // args)).doomEmacs;
   mkDoomDir = args: writeTextDir "init.el" (toInit args);
   minimalDoomDir = mkDoomDir { config = [ "default" ]; };
-  fullDoomDir = (makeDoomPackages (common // { doomDir = emptyDirectory; })).doomDirWithAllModules;
+  allModsDoomDir = (makeDoomPackages (common // { doomDir = emptyDirectory; })).doomDirWithAllModules;
+  allFlagsDoomDir = (makeDoomPackages (common // { doomDir = emptyDirectory; })).doomDirWithAllModulesAndFlags;
   doomTest = name: init: doomArgs: testers.testEqualContents {
     assertion = "name = ${name}; modules = ${toPretty {} init}; args = ${toPretty {} doomArgs};";
     expected = writeText "doom-expected" "Doom functions";
@@ -66,7 +67,8 @@ in {
   minimalEmacs = (makeDoomPackages (common // {
     doomDir = minimalDoomDir;
   })).emacsWithDoom;
-  full = mkDoom { doomDir = fullDoomDir; };
+  allModules = mkDoom { doomDir = allModsDoomDir; };
+  allModulesAndFlags = mkDoom { doomDir = allFlagsDoomDir; };
   example = mkDoom { doomDir = ./doomdirs/example; };
   example-without-loader = mkDoom {
     doomDir = ./doomdirs/example;
diff --git a/default.nix b/default.nix
index ab543d7..e460f7e 100644
--- a/default.nix
+++ b/default.nix
@@ -71,6 +71,22 @@ let
     ${runtimeShell} ${doomSource}/bin/doomscript ${./build-helpers/full-init} -o $out
   '';
 
+  doomDirWithAllModulesAndFlags = runCommandLocal "doom-full-init"
+    {
+      env = {
+        EMACS = lib.getExe emacs;
+        # Enable this to troubleshoot failures at this step.
+        #DEBUG = "1";
+      };
+      # We set DOOMLOCALDIR somewhere harmless below to stop Doom from trying to
+      # create it somewhere read-only.
+    } ''
+    mkdir $out
+    export DOOMLOCALDIR=$(mktemp -d)
+    ${runtimeShell} ${doomSource}/bin/doomscript ${./build-helpers/full-init} --flags -o $out
+  '';
+
+
   # Step 1: determine which Emacs packages to pull in.
   #
   # Inputs: Doom, original DOOMDIR (only init.el and packages.el are used).
@@ -426,5 +442,5 @@ let
   '';
 in
 {
-  inherit doomDirWithAllModules doomEmacs emacsWithDoom;
+  inherit doomDirWithAllModules doomDirWithAllModulesAndFlags doomEmacs emacsWithDoom;
 }