diff --git a/.bazelrc b/.bazelrc
index ca20a1717..fd3add09e 100644
--- a/.bazelrc
+++ b/.bazelrc
@@ -12,6 +12,8 @@ test --test_env=LANG=C.UTF-8 --test_env=LOCALE_ARCHIVE
 
 # Platform / Toolchain Selection
 # ------------------------------
+build:linux-nixpkgs --config=nixpkgs
+build:macos-nixpkgs --config=nixpkgs
 build:nixpkgs --host_platform=@io_tweag_rules_nixpkgs//nixpkgs/platforms:host
 # Use this configuration when targeting Windows. Eventually this will
 # no longer be required:
diff --git a/.github/workflows/workflow.yaml b/.github/workflows/workflow.yaml
index 0da0b3c0f..7d8675d5e 100644
--- a/.github/workflows/workflow.yaml
+++ b/.github/workflows/workflow.yaml
@@ -24,10 +24,13 @@ jobs:
           nix_path: nixpkgs=./nixpkgs/default.nix
       - name: Configure
         run: |
-          [[ ${{ matrix.os }} == macos ]] && EXTRA_CONFIG=--config=macos-nixpkgs
+          case ${{ matrix.os }} in
+            macos) BUILD_CONFIG=macos-nixpkgs;;
+            ubuntu) BUILD_CONFIG=linux-nixpkgs;;
+          esac
           cat >.bazelrc.local <<EOF
           common --config=ci
-          build --config=nixpkgs $EXTRA_CONFIG
+          build --config=$BUILD_CONFIG
           EOF
       - name: Check Bazel version
         run: |
diff --git a/.mergify.yml b/.mergify.yml
index 3040d7135..5cf37de9a 100644
--- a/.mergify.yml
+++ b/.mergify.yml
@@ -1,9 +1,10 @@
 pull_request_rules:
   - name: automatic merge
     conditions:
-      - 'status-success~=Build & Test - macOS \(Nixpkgs\).*'
-      - 'status-success~=Build & Test - macOS \(bindist\).*'
-      - "status-success~=buildkite/rules-haskell(|/pr)"
+      - 'status-success~=Build & Test - Nixpkgs \(ubuntu\).*'
+      - 'status-success~=Build & Test - Nixpkgs \(macos\).*'
+      - 'status-success~=Build & Test - bindist \(ubuntu\).*'
+      - 'status-success~=Build & Test - bindist \(macos\).*'
       - "status-success=tweag.rules_haskell"
       - "status-success=deploy/netlify"
       - "#approved-reviews-by>=1"
diff --git a/README.md b/README.md
index c04b23e8a..a304b6993 100644
--- a/README.md
+++ b/README.md
@@ -2,7 +2,7 @@
 
 # Haskell rules for [Bazel][bazel]
 
-![Continuous integration](https://github.com/tweag/rules_haskell/workflows/Continuous%20integration/badge.svg)
+[![Continuous integration](https://github.com/tweag/rules_haskell/workflows/Continuous%20integration/badge.svg)](https://github.com/tweag/rules_haskell/actions?query=branch%3Amaster)
 [![Build Status](https://dev.azure.com/tweag/rules_haskell/_apis/build/status/tweag.rules_haskell?branchName=master)](https://dev.azure.com/tweag/rules_haskell/_build/latest?definitionId=1?branchName=master)
 
 Bazel automates building and testing software. It scales to very large
@@ -254,7 +254,7 @@ This chooses the `cc_toolchain` bundled with GHC.
 ### Configuring your platform
 
 `rules_haskell` can be built and tested on Linux, MacOS, and Windows. Depending
-on the platform GHC can be provisioned using Nixpkgs or by downloading a binary
+on the platform GHC can be provisioned using nixpkgs or by downloading a binary
 distribution. In case of nixpkgs other toolchains (C compiler, Python, shell
 tools) will also be provided by nixpkgs, in case of bindist they will be taken
 from the environment (`$PATH`). The following `--config` options select the
@@ -262,18 +262,18 @@ corresponding combination of operating system and GHC distribution:
 
 |                     |      Linux      |      MacOS      |      Windows      |
 | ------------------- | --------------- | --------------- | ----------------- |
-| Nixpkgs             | (unneeded)      | `macos-nixpkgs` | (unsupported)     |
-| Binary distribution | `linux-bindist` | `macos-bindist` | `windows-bindist` |
+| nixpkgs             | `linux-nixpkgs` | `macos-nixpkgs` |                   |
+| binary distribution | `linux-bindist` | `macos-bindist` | `windows-bindist` |
 
 Hint: You can use Bazel's `--announce_rc` flag to see what options are being
 used for a command in a specific configuration. E.g.
 ```
-$ bazel build //tests:run-tests --config linux-bindist --nobuild --announce_rc
+$ bazel build //tests:run-tests --config linux-nixpkgs --nobuild --announce_rc
 ```
 
 Hint: To avoid repetition you can add your configuration to `.bazelrc.local`.
 ```
-echo "build --config=linux-bindist" >>.bazelrc.local
+echo "build --config=linux-nixpkgs" >>.bazelrc.local
 ```
 
 ### Saving common command-line flags to a file
diff --git a/tests/haddock_protobuf/BUILD.bazel b/tests/haddock_protobuf/BUILD.bazel
index 968dee9d5..e7cfab6bc 100644
--- a/tests/haddock_protobuf/BUILD.bazel
+++ b/tests/haddock_protobuf/BUILD.bazel
@@ -9,10 +9,12 @@ load("//haskell:protobuf.bzl", "haskell_proto_library")
 proto_library(
     name = "hello_world_proto",
     srcs = ["hello_world.proto"],
+    tags = ["requires_proto"],
 )
 
 haskell_proto_library(
     name = "hello_world_haskell_proto",
+    tags = ["requires_proto"],
     deps = [
         ":hello_world_proto",
     ],
@@ -21,6 +23,7 @@ haskell_proto_library(
 haskell_library(
     name = "hello_world_haskell",
     srcs = ["HelloWorld.hs"],  # Just imports the proto and does something trivial
+    tags = ["requires_proto"],
     deps = [
         ":hello_world_haskell_proto",
         "@stackage//:base",
@@ -30,6 +33,7 @@ haskell_library(
 # Haddocks version A: depend on just the haskell_library
 haskell_doc(
     name = "haddocks_a",
+    tags = ["requires_proto"],
     deps = [
         ":hello_world_haskell",
     ],
@@ -38,6 +42,7 @@ haskell_doc(
 # Haddocks version B: depend on both haskell_library and haskell_proto_library
 haskell_doc(
     name = "haddocks_b",
+    tags = ["requires_proto"],
     deps = [
         ":hello_world_haskell",
         ":hello_world_haskell_proto",
diff --git a/tests/haskell_proto_simple/BUILD.bazel b/tests/haskell_proto_simple/BUILD.bazel
index 9d39a6eec..acee8aae6 100644
--- a/tests/haskell_proto_simple/BUILD.bazel
+++ b/tests/haskell_proto_simple/BUILD.bazel
@@ -12,11 +12,13 @@ load(
 proto_library(
     name = "foo",
     srcs = ["foo.proto"],
+    tags = ["requires_proto"],
     deps = ["@com_google_protobuf//:descriptor_proto"],
 )
 
 haskell_proto_library(
     name = "foo_haskell",
+    tags = ["requires_proto"],
     deps = [
         ":foo",
     ],
@@ -25,9 +27,7 @@ haskell_proto_library(
 haskell_library(
     name = "hs-lib",
     srcs = ["Bar.hs"],
-    tags = [
-        "requires_proto",
-    ],
+    tags = ["requires_proto"],
     visibility = ["//visibility:public"],
     deps = [
         ":foo_haskell",