diff --git a/docker-compose.yml b/docker-compose.yml
index 6f8c8544b..caf58c453 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -454,6 +454,9 @@ services:
       dockerfile: localinfra/web.Dockerfile
     restart: unless-stopped
     environment:
+      # run pnpm non-interactively in the container: the startup install may need
+      # to repurge node_modules and would otherwise abort without a TTY
+      CI: "true"
       BOBBIN_URL: https://bobbin.tngl.boltless.dev
       # browser-reachable appview for authed xrpc; host must match the
       # appview's TANGLED_APPVIEW_HOST so the service-auth aud lines up