diff --git a/.github/workflows/nix-action-8.17.yml b/.github/workflows/nix-action-8.17.yml
index 8f4ffd81..9b569d57 100644
--- a/.github/workflows/nix-action-8.17.yml
+++ b/.github/workflows/nix-action-8.17.yml
@@ -34,11 +34,12 @@ jobs:
       uses: cachix/install-nix-action@v27
       with:
         nix_path: nixpkgs=channel:nixpkgs-unstable
-    - name: Cachix setup coq
+    - name: Cachix setup au-cobra
       uses: cachix/cachix-action@v15
       with:
-        extraPullNames: coq-community, metacoq
-        name: coq
+        authToken: ${{ secrets.CACHIX_AUTH_TOKEN }}
+        extraPullNames: coq, coq-community, metacoq
+        name: au-cobra
     - id: stepCheck
       name: Checking presence of CI target ConCert
       run: "nb_dry_run=$(NIXPKGS_ALLOW_UNFREE=1 nix-build --no-out-link \\\n   --argstr\
@@ -109,11 +110,12 @@ jobs:
       uses: cachix/install-nix-action@v27
       with:
         nix_path: nixpkgs=channel:nixpkgs-unstable
-    - name: Cachix setup coq
+    - name: Cachix setup au-cobra
       uses: cachix/cachix-action@v15
       with:
-        extraPullNames: coq-community, metacoq
-        name: coq
+        authToken: ${{ secrets.CACHIX_AUTH_TOKEN }}
+        extraPullNames: coq, coq-community, metacoq
+        name: au-cobra
     - id: stepCheck
       name: Checking presence of CI target QuickChick
       run: "nb_dry_run=$(NIXPKGS_ALLOW_UNFREE=1 nix-build --no-out-link \\\n   --argstr\
@@ -171,11 +173,12 @@ jobs:
       uses: cachix/install-nix-action@v27
       with:
         nix_path: nixpkgs=channel:nixpkgs-unstable
-    - name: Cachix setup coq
+    - name: Cachix setup au-cobra
       uses: cachix/cachix-action@v15
       with:
-        extraPullNames: coq-community, metacoq
-        name: coq
+        authToken: ${{ secrets.CACHIX_AUTH_TOKEN }}
+        extraPullNames: coq, coq-community, metacoq
+        name: au-cobra
     - id: stepCheck
       name: Checking presence of CI target coq
       run: "nb_dry_run=$(NIXPKGS_ALLOW_UNFREE=1 nix-build --no-out-link \\\n   --argstr\
@@ -218,11 +221,12 @@ jobs:
       uses: cachix/install-nix-action@v27
       with:
         nix_path: nixpkgs=channel:nixpkgs-unstable
-    - name: Cachix setup coq
+    - name: Cachix setup au-cobra
       uses: cachix/cachix-action@v15
       with:
-        extraPullNames: coq-community, metacoq
-        name: coq
+        authToken: ${{ secrets.CACHIX_AUTH_TOKEN }}
+        extraPullNames: coq, coq-community, metacoq
+        name: au-cobra
     - id: stepCheck
       name: Checking presence of CI target metacoq
       run: "nb_dry_run=$(NIXPKGS_ALLOW_UNFREE=1 nix-build --no-out-link \\\n   --argstr\
@@ -289,11 +293,12 @@ jobs:
       uses: cachix/install-nix-action@v27
       with:
         nix_path: nixpkgs=channel:nixpkgs-unstable
-    - name: Cachix setup coq
+    - name: Cachix setup au-cobra
       uses: cachix/cachix-action@v15
       with:
-        extraPullNames: coq-community, metacoq
-        name: coq
+        authToken: ${{ secrets.CACHIX_AUTH_TOKEN }}
+        extraPullNames: coq, coq-community, metacoq
+        name: au-cobra
     - id: stepCheck
       name: Checking presence of CI target stdpp
       run: "nb_dry_run=$(NIXPKGS_ALLOW_UNFREE=1 nix-build --no-out-link \\\n   --argstr\
diff --git a/.github/workflows/nix-action-8.18.yml b/.github/workflows/nix-action-8.18.yml
index 5ea8a094..f71a3633 100644
--- a/.github/workflows/nix-action-8.18.yml
+++ b/.github/workflows/nix-action-8.18.yml
@@ -34,11 +34,12 @@ jobs:
       uses: cachix/install-nix-action@v27
       with:
         nix_path: nixpkgs=channel:nixpkgs-unstable
-    - name: Cachix setup coq
+    - name: Cachix setup au-cobra
       uses: cachix/cachix-action@v15
       with:
-        extraPullNames: coq-community, metacoq
-        name: coq
+        authToken: ${{ secrets.CACHIX_AUTH_TOKEN }}
+        extraPullNames: coq, coq-community, metacoq
+        name: au-cobra
     - id: stepCheck
       name: Checking presence of CI target ConCert
       run: "nb_dry_run=$(NIXPKGS_ALLOW_UNFREE=1 nix-build --no-out-link \\\n   --argstr\
@@ -109,11 +110,12 @@ jobs:
       uses: cachix/install-nix-action@v27
       with:
         nix_path: nixpkgs=channel:nixpkgs-unstable
-    - name: Cachix setup coq
+    - name: Cachix setup au-cobra
       uses: cachix/cachix-action@v15
       with:
-        extraPullNames: coq-community, metacoq
-        name: coq
+        authToken: ${{ secrets.CACHIX_AUTH_TOKEN }}
+        extraPullNames: coq, coq-community, metacoq
+        name: au-cobra
     - id: stepCheck
       name: Checking presence of CI target QuickChick
       run: "nb_dry_run=$(NIXPKGS_ALLOW_UNFREE=1 nix-build --no-out-link \\\n   --argstr\
@@ -171,11 +173,12 @@ jobs:
       uses: cachix/install-nix-action@v27
       with:
         nix_path: nixpkgs=channel:nixpkgs-unstable
-    - name: Cachix setup coq
+    - name: Cachix setup au-cobra
       uses: cachix/cachix-action@v15
       with:
-        extraPullNames: coq-community, metacoq
-        name: coq
+        authToken: ${{ secrets.CACHIX_AUTH_TOKEN }}
+        extraPullNames: coq, coq-community, metacoq
+        name: au-cobra
     - id: stepCheck
       name: Checking presence of CI target coq
       run: "nb_dry_run=$(NIXPKGS_ALLOW_UNFREE=1 nix-build --no-out-link \\\n   --argstr\
@@ -218,11 +221,12 @@ jobs:
       uses: cachix/install-nix-action@v27
       with:
         nix_path: nixpkgs=channel:nixpkgs-unstable
-    - name: Cachix setup coq
+    - name: Cachix setup au-cobra
       uses: cachix/cachix-action@v15
       with:
-        extraPullNames: coq-community, metacoq
-        name: coq
+        authToken: ${{ secrets.CACHIX_AUTH_TOKEN }}
+        extraPullNames: coq, coq-community, metacoq
+        name: au-cobra
     - id: stepCheck
       name: Checking presence of CI target metacoq
       run: "nb_dry_run=$(NIXPKGS_ALLOW_UNFREE=1 nix-build --no-out-link \\\n   --argstr\
@@ -289,11 +293,12 @@ jobs:
       uses: cachix/install-nix-action@v27
       with:
         nix_path: nixpkgs=channel:nixpkgs-unstable
-    - name: Cachix setup coq
+    - name: Cachix setup au-cobra
       uses: cachix/cachix-action@v15
       with:
-        extraPullNames: coq-community, metacoq
-        name: coq
+        authToken: ${{ secrets.CACHIX_AUTH_TOKEN }}
+        extraPullNames: coq, coq-community, metacoq
+        name: au-cobra
     - id: stepCheck
       name: Checking presence of CI target stdpp
       run: "nb_dry_run=$(NIXPKGS_ALLOW_UNFREE=1 nix-build --no-out-link \\\n   --argstr\
diff --git a/.github/workflows/nix-action-8.19.yml b/.github/workflows/nix-action-8.19.yml
index 8ee25ffe..c6cf0a7d 100644
--- a/.github/workflows/nix-action-8.19.yml
+++ b/.github/workflows/nix-action-8.19.yml
@@ -34,11 +34,12 @@ jobs:
       uses: cachix/install-nix-action@v27
       with:
         nix_path: nixpkgs=channel:nixpkgs-unstable
-    - name: Cachix setup coq
+    - name: Cachix setup au-cobra
       uses: cachix/cachix-action@v15
       with:
-        extraPullNames: coq-community, metacoq
-        name: coq
+        authToken: ${{ secrets.CACHIX_AUTH_TOKEN }}
+        extraPullNames: coq, coq-community, metacoq
+        name: au-cobra
     - id: stepCheck
       name: Checking presence of CI target ConCert
       run: "nb_dry_run=$(NIXPKGS_ALLOW_UNFREE=1 nix-build --no-out-link \\\n   --argstr\
@@ -109,11 +110,12 @@ jobs:
       uses: cachix/install-nix-action@v27
       with:
         nix_path: nixpkgs=channel:nixpkgs-unstable
-    - name: Cachix setup coq
+    - name: Cachix setup au-cobra
       uses: cachix/cachix-action@v15
       with:
-        extraPullNames: coq-community, metacoq
-        name: coq
+        authToken: ${{ secrets.CACHIX_AUTH_TOKEN }}
+        extraPullNames: coq, coq-community, metacoq
+        name: au-cobra
     - id: stepCheck
       name: Checking presence of CI target QuickChick
       run: "nb_dry_run=$(NIXPKGS_ALLOW_UNFREE=1 nix-build --no-out-link \\\n   --argstr\
@@ -171,11 +173,12 @@ jobs:
       uses: cachix/install-nix-action@v27
       with:
         nix_path: nixpkgs=channel:nixpkgs-unstable
-    - name: Cachix setup coq
+    - name: Cachix setup au-cobra
       uses: cachix/cachix-action@v15
       with:
-        extraPullNames: coq-community, metacoq
-        name: coq
+        authToken: ${{ secrets.CACHIX_AUTH_TOKEN }}
+        extraPullNames: coq, coq-community, metacoq
+        name: au-cobra
     - id: stepCheck
       name: Checking presence of CI target coq
       run: "nb_dry_run=$(NIXPKGS_ALLOW_UNFREE=1 nix-build --no-out-link \\\n   --argstr\
@@ -218,11 +221,12 @@ jobs:
       uses: cachix/install-nix-action@v27
       with:
         nix_path: nixpkgs=channel:nixpkgs-unstable
-    - name: Cachix setup coq
+    - name: Cachix setup au-cobra
       uses: cachix/cachix-action@v15
       with:
-        extraPullNames: coq-community, metacoq
-        name: coq
+        authToken: ${{ secrets.CACHIX_AUTH_TOKEN }}
+        extraPullNames: coq, coq-community, metacoq
+        name: au-cobra
     - id: stepCheck
       name: Checking presence of CI target metacoq
       run: "nb_dry_run=$(NIXPKGS_ALLOW_UNFREE=1 nix-build --no-out-link \\\n   --argstr\
@@ -289,11 +293,12 @@ jobs:
       uses: cachix/install-nix-action@v27
       with:
         nix_path: nixpkgs=channel:nixpkgs-unstable
-    - name: Cachix setup coq
+    - name: Cachix setup au-cobra
       uses: cachix/cachix-action@v15
       with:
-        extraPullNames: coq-community, metacoq
-        name: coq
+        authToken: ${{ secrets.CACHIX_AUTH_TOKEN }}
+        extraPullNames: coq, coq-community, metacoq
+        name: au-cobra
     - id: stepCheck
       name: Checking presence of CI target stdpp
       run: "nb_dry_run=$(NIXPKGS_ALLOW_UNFREE=1 nix-build --no-out-link \\\n   --argstr\
diff --git a/.nix/config.nix b/.nix/config.nix
index 9777a6df..1db0272d 100644
--- a/.nix/config.nix
+++ b/.nix/config.nix
@@ -32,17 +32,5 @@
   cachix.coq-community = {};
   cachix.metacoq = {};
 
-  ## If you have write access to one of these caches you can
-  ## provide the auth token or signing key through a secret
-  ## variable on GitHub. Then, you should give the variable
-  ## name here. For instance, coq-community projects can use
-  ## the following line instead of the one above:
-  # cachix.coq-community.authToken = "CACHIX_AUTH_TOKEN";
-
-  ## Or if you have a signing key for a given Cachix cache:
-  # cachix.my-cache.signingKey = "CACHIX_SIGNING_KEY"
-
-  ## Note that here, CACHIX_AUTH_TOKEN and CACHIX_SIGNING_KEY
-  ## are the names of secret variables. They are set in
-  ## GitHub's web interface.
+  cachix.au-cobra.authToken = "CACHIX_AUTH_TOKEN";
 }