diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 54ab43c..d00cb5e 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -10,7 +10,7 @@ jobs:
       - uses: actions/checkout@v4
 
       - name: Install devbox
-        uses: jetify-com/devbox-install-action@v0.14.0
+        uses: jetify-com/devbox-install-action@v0.15.0
 
       - name: Run tests
         # retry to get around "resource busy"
diff --git a/devbox.json b/devbox.json
index be4d95c..cb44cd3 100644
--- a/devbox.json
+++ b/devbox.json
@@ -2,7 +2,7 @@
   "$schema": "https://raw.githubusercontent.com/jetify-com/devbox/0.13.6/.schema/devbox.schema.json",
   "packages": [
     "nodejs@24",
-    "gren@0.6.5",
+    "gren@0.6.6",
     "curl@latest",
     "jq@latest",
     "sqlite@latest"
diff --git a/devbox.lock b/devbox.lock
index 0f8f499..19b8442 100644
--- a/devbox.lock
+++ b/devbox.lock
@@ -128,51 +128,51 @@
     "github:NixOS/nixpkgs/nixpkgs-unstable": {
       "resolved": "github:NixOS/nixpkgs/3549532663732bfd89993204d40543e9edaec4f2?lastModified=1742272065&narHash=sha256-ud8vcSzJsZ%2FCK%2Br8%2Fv0lyf4yUntVmDq6Z0A41ODfWbE%3D"
     },
-    "gren@0.6.5": {
-      "last_modified": "2026-04-16T08:46:55Z",
-      "resolved": "github:NixOS/nixpkgs/b86751bc4085f48661017fa226dee99fab6c651b#gren",
+    "gren@0.6.6": {
+      "last_modified": "2026-06-27T07:37:20Z",
+      "resolved": "github:NixOS/nixpkgs/3d46470bb3030020f7e1361f33514854f5bfa86d#gren",
       "source": "devbox-search",
-      "version": "0.6.5",
+      "version": "0.6.6",
       "systems": {
         "aarch64-darwin": {
           "outputs": [
             {
               "name": "out",
-              "path": "/nix/store/kijfkwvkxkfp8vpzj630q99k5cymdgx2-gren-0.6.5",
+              "path": "/nix/store/9vyc22ydaxkys8n5vkhjrxq6zv5krs9f-gren-0.6.6",
               "default": true
             }
           ],
-          "store_path": "/nix/store/kijfkwvkxkfp8vpzj630q99k5cymdgx2-gren-0.6.5"
+          "store_path": "/nix/store/9vyc22ydaxkys8n5vkhjrxq6zv5krs9f-gren-0.6.6"
         },
         "aarch64-linux": {
           "outputs": [
             {
               "name": "out",
-              "path": "/nix/store/a2za3hav09hg1amcj225b913dyfjs2wp-gren-0.6.5",
+              "path": "/nix/store/3rlsgdzk74p5zl18v7galjnv9a1c2bc8-gren-0.6.6",
               "default": true
             }
           ],
-          "store_path": "/nix/store/a2za3hav09hg1amcj225b913dyfjs2wp-gren-0.6.5"
+          "store_path": "/nix/store/3rlsgdzk74p5zl18v7galjnv9a1c2bc8-gren-0.6.6"
         },
         "x86_64-darwin": {
           "outputs": [
             {
               "name": "out",
-              "path": "/nix/store/0mrp2wghqzmlcqc6nrfpv9l7s1p3kmcg-gren-0.6.5",
+              "path": "/nix/store/56y0sjs175cqpwdfvq00yy29ibcyzbc8-gren-0.6.6",
               "default": true
             }
           ],
-          "store_path": "/nix/store/0mrp2wghqzmlcqc6nrfpv9l7s1p3kmcg-gren-0.6.5"
+          "store_path": "/nix/store/56y0sjs175cqpwdfvq00yy29ibcyzbc8-gren-0.6.6"
         },
         "x86_64-linux": {
           "outputs": [
             {
               "name": "out",
-              "path": "/nix/store/3bc06xrds99f1cdhymrfyv8nwi43q8bp-gren-0.6.5",
+              "path": "/nix/store/8h4kkbn092a271i3277v4azsryw5vw0b-gren-0.6.6",
               "default": true
             }
           ],
-          "store_path": "/nix/store/3bc06xrds99f1cdhymrfyv8nwi43q8bp-gren-0.6.5"
+          "store_path": "/nix/store/8h4kkbn092a271i3277v4azsryw5vw0b-gren-0.6.6"
         }
       }
     },
diff --git a/gren.json b/gren.json
index 582e016..5b97da0 100644
--- a/gren.json
+++ b/gren.json
@@ -4,7 +4,7 @@
     "source-directories": [
         "src"
     ],
-    "gren-version": "0.6.5",
+    "gren-version": "0.6.6",
     "dependencies": {
         "direct": {
             "blaix/gren-effectful-tests": "6.0.0",