diff --git a/.github/workflows/quest.yml b/.github/workflows/quest.yml
index ce282e9b47b..6118d649ddb 100644
--- a/.github/workflows/quest.yml
+++ b/.github/workflows/quest.yml
@@ -47,12 +47,16 @@ jobs:
       - uses: DeterminateSystems/nix-installer-action@1d87d45818068401a10cf16bdc5f00b24994a83f # main
         with:
           determinate: false
-          # Trust the flake's cachix substituter, which holds the dev shell;
-          # see check.yml.
+          # Trust the flake's cachix substituter, which holds the quest build
+          # as part of the dev shell closure; see check.yml.
           extra-conf: |
             extra-substituters = https://kixelated.cachix.org
             extra-trusted-public-keys = kixelated.cachix.org-1:CmFcV0lyM6KuVM2m9mih0q4SrAa0XyCsiM7GHrz3KKk=
 
       # The whole tree, unscoped: a push has no base to diff against.
+      #
+      # Only the quest package, not `nix develop`: the dev shell compiles
+      # uniffi-bindgen-go from source whenever cache.yml hasn't pushed it for
+      # this flake.lock yet, which ran past the timeout.
       - name: Check
-        run: nix develop --command quest check
+        run: nix run .#quest -- check
diff --git a/flake.nix b/flake.nix
index 1d10877644e..c537b778b20 100644
--- a/flake.nix
+++ b/flake.nix
@@ -427,6 +427,8 @@
 
         # Apply our overlay to get the package definitions
         overlayPkgs = pkgs.extend self.overlays.default;
+
+        quest-cli = quest.packages.${system}.default;
       in
       {
         packages = (rec {
@@ -460,6 +462,10 @@
 
           inherit uniffi-bindgen-dart;
 
+          # The quest CLI alone, so quest.yml can validate the tree without
+          # realising the whole dev shell.
+          quest = quest-cli;
+
           # Bundle of packaging + repo-publish tooling, pinned via flake.lock.
           # CI builds this and prepends its bin/ to $PATH so subsequent steps
           # use the same versions a local `nix develop` user would.
@@ -504,7 +510,7 @@
             ++ goDeps
             ++ dartDeps
             ++ devTools
-            ++ [ quest.packages.${system}.default ];
+            ++ [ quest-cli ];
 
           # jemalloc's configure uses -O0 test builds, which conflict with
           # Nix's _FORTIFY_SOURCE hardening (requires -O).