diff --git a/.circleci/config.yml b/.circleci/config.yml
index 32360b95..5088f0ea 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -107,7 +107,8 @@ jobs:
       - image: quay.io/prometheus/golang-builder:1.20-base
     steps:
       - checkout
-      - run: go install github.com/monitoring-mixins/mixtool/cmd/mixtool@latest
+      # pin the mixtool version until https://github.com/monitoring-mixins/mixtool/issues/135 is merged.
+      - run: go install github.com/monitoring-mixins/mixtool/cmd/mixtool@2282201396b69055bb0f92f187049027a16d2130
       - run: go install github.com/google/go-jsonnet/cmd/jsonnetfmt@latest
       - run: go install github.com/jsonnet-bundler/jsonnet-bundler/cmd/jb@latest
       - run: make -C doc/alertmanager-mixin lint
diff --git a/doc/alertmanager-mixin/Makefile b/doc/alertmanager-mixin/Makefile
index 314e4b38..9ce9a9f4 100644
--- a/doc/alertmanager-mixin/Makefile
+++ b/doc/alertmanager-mixin/Makefile
@@ -20,7 +20,6 @@ lint: build
 
 	mixtool lint mixin.libsonnet
 
-
 dashboards_out: mixin.libsonnet config.libsonnet $(wildcard dashboards/*)
 	@mkdir -p dashboards_out
 	jsonnet -J vendor -m dashboards_out dashboards.jsonnet