diff --git a/.dockerignore b/.dockerignore
new file mode 100644
index 0000000..477752a
--- /dev/null
+++ b/.dockerignore
@@ -0,0 +1,11 @@
+.dockerignore
+.git
+.github
+.gitignore
+Makefile
+README.md
+bump-info.json
+coco-dev
+docker-compose.build.yml
+package.json
+tests
diff --git a/.github/workflows/build-docker.yml b/.github/workflows/build-docker.yml
index 17c5b5e..04b7089 100644
--- a/.github/workflows/build-docker.yml
+++ b/.github/workflows/build-docker.yml
@@ -1,17 +1,26 @@
 name: Build Docker Image
 
 on:
-  pull_request:
   push:
     branches:
       - '**'
       - '!main'
   workflow_dispatch:
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 permissions:
   contents: write
 
 jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - run: make lint
+
   create_tag:
     runs-on: ubuntu-latest
     outputs:
@@ -37,27 +46,42 @@ jobs:
           - ubuntu-24.04-arm
 
     steps:
+      - uses: actions/checkout@v4
+
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
 
       - name: Login to DockerHub
-        uses: docker/login-action@v3 
+        uses: docker/login-action@v3
         with:
           username: ${{ secrets.DOCKERHUB_USERNAME }}
           password: ${{ secrets.DOCKERHUB_TOKEN }}
 
-      - name: Build and push image
+      - name: Build and load image
         env:
           RELEASE_TAG: ${{ needs.create_tag.outputs.release_tag }}
         uses: docker/build-push-action@v6
         with:
-          push: ${{ startsWith(github.ref, 'refs/tags') }}
+          load: true
           tags: jamieleecho/coco-dev:${{ env.RELEASE_TAG }}-${{ matrix.os }}
-          cache-from: type=gha
-          cache-to: type=gha,mode=max
+          cache-from: type=gha,scope=${{ matrix.os }}
+          cache-to: type=gha,mode=max,scope=${{ matrix.os }}
+
+      - name: Smoke test
+        env:
+          RELEASE_TAG: ${{ needs.create_tag.outputs.release_tag }}
+        run: make test TAG=jamieleecho/coco-dev:${{ env.RELEASE_TAG }}-${{ matrix.os }}
 
-      - uses: actions/checkout@v3
+      - name: Image size
+        env:
+          RELEASE_TAG: ${{ needs.create_tag.outputs.release_tag }}
+        run: make size TAG=jamieleecho/coco-dev:${{ env.RELEASE_TAG }}-${{ matrix.os }}
+
+      - name: Push image
         if: startsWith(github.ref, 'refs/tags')
+        env:
+          RELEASE_TAG: ${{ needs.create_tag.outputs.release_tag }}
+        run: docker push jamieleecho/coco-dev:${{ env.RELEASE_TAG }}-${{ matrix.os }}
 
       - name: Update repo description
         uses: peter-evans/dockerhub-description@v3
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..6ba4b02
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,63 @@
+.DEFAULT_GOAL := help
+.PHONY: help build test shell lint size push clean
+
+IMAGE := jamieleecho/coco-dev
+VERSION := $(shell sed -nE 's/.*"version" *: *"([^"]+)".*/\1/p' package.json)
+TAG ?= $(IMAGE):$(VERSION)
+SHELLCHECK_IMAGE := koalaman/shellcheck-alpine:stable
+
+help:
+	@echo "coco-dev Makefile targets:"
+	@echo ""
+	@echo "  make build  Build the docker image and tag as $(TAG)"
+	@echo "  make test   Run smoke tests inside the built image"
+	@echo "  make shell  Drop into a one-off bash shell in the image"
+	@echo "  make lint   Run shellcheck on the shell scripts"
+	@echo "  make size   Print the size of the built image"
+	@echo "  make push   Push the image to Docker Hub"
+	@echo "  make clean  Remove the local image"
+	@echo "  make help   Show this help (default)"
+	@echo ""
+	@echo "Override the tag with TAG=...  (e.g. make test TAG=jamieleecho/coco-dev:0.79)"
+
+build:
+	docker compose -f docker-compose.build.yml build
+
+test:
+	docker run --rm -v "$(CURDIR)/tests:/sources:ro" $(TAG) bash -euc '\
+		echo "[1/4] java_grinder -> .bin"; \
+		work=$$(mktemp -d); cp /sources/java_grinder/* $$work/; cd $$work; \
+		javac Hello.java; \
+		java_grinder Hello.class Hello.asm trs80_coco; \
+		naken_asm -l -type bin -o Hello.bin Hello.asm; \
+		test -s Hello.bin; \
+		echo "[2/4] basto6809todsk -> .DSK"; \
+		work=$$(mktemp -d); cp /sources/basto6809/* $$work/; cd $$work; \
+		basto6809todsk HELLO.BAS; \
+		test -s HELLO.DSK; \
+		echo "[3/4] mcbasic -> .c10"; \
+		work=$$(mktemp -d); cp /sources/mcbasic/* $$work/; cd $$work; \
+		mcbasic MC10HELLO.BAS; \
+		test -s MC10HELLO.c10; \
+		echo "[4/4] cmoc --os9 -> OS-9 module"; \
+		work=$$(mktemp -d); cp /sources/cmoc-os9/* $$work/; cd $$work; \
+		cmoc --os9 hello.c; \
+		test -s hello; \
+		echo "All smoke tests passed."'
+
+shell:
+	docker run --rm -it $(TAG) bash
+
+lint:
+	docker run --rm -v "$(CURDIR):/work" -w /work $(SHELLCHECK_IMAGE) \
+		shellcheck coco-dev utils/basto6809todsk
+
+size:
+	@bytes=$$(docker image inspect --format='{{.Size}}' $(TAG)); \
+	awk -v b=$$bytes 'BEGIN { printf "%s: %.2f MB\n", "$(TAG)", b/1024/1024 }'
+
+push:
+	docker push $(TAG)
+
+clean:
+	-docker rmi $(TAG)
diff --git a/README.md b/README.md
index 215e5d8..6cf92d6 100644
--- a/README.md
+++ b/README.md
@@ -75,5 +75,9 @@ your project folder and open the folder in VS Code. See the [documentation](http
 # Start the Docker application if it is not already running
 git clone https://github.com/jamieleecho/coco-dev.git
 cd coco-dev
-./build
+make build
 ```
+
+Run `make help` to see the available targets. After building, `make test`
+runs a quick smoke test that exercises CMOC, BasTo6809, mcbasic, and Java
+Grinder against the built image.
diff --git a/build b/build
deleted file mode 100755
index a393b73..0000000
--- a/build
+++ /dev/null
@@ -1,4 +0,0 @@
-#!/usr/bin/env bash
-
-# Build and tag are now handled in a single step
-docker compose -f docker-compose.build.yml build
diff --git a/coco-dev b/coco-dev
index 37c55d2..3fd74fe 100755
--- a/coco-dev
+++ b/coco-dev
@@ -1,8 +1,8 @@
 #!/usr/bin/env bash
 
 
-if [[ $* = *[!\ ]* ]]; then
-  params=( "$*" )
+if [[ $# -gt 0 ]]; then
+  params=( "$@" )
 else
   params=( bash )
 fi
@@ -12,11 +12,11 @@ COCO_DEV_IMAGE=jamieleecho/coco-dev:0.79
 case "$(uname -s)" in
 
    Darwin)
-     docker run -it --rm -w "$(pwd | sed -e s#^/[Uu][Ss][Ee][Rr][Ss]#/home#)" -v "$HOME"/..:/home -e HOME=/home/"$USER" ${COCO_DEV_IMAGE} ${params[@]}
+     docker run -it --rm -w "$(pwd | sed -e s#^/[Uu][Ss][Ee][Rr][Ss]#/home#)" -v "$HOME"/..:/home -e HOME=/home/"$USER" "${COCO_DEV_IMAGE}" "${params[@]}"
      ;;
 
    Linux)
-     docker run -u "$(id -u):$(id -g)" -it --rm -w "$(pwd)" -v /etc/passwd:/etc/passwd -v "$HOME"/..:/home -e HOME=/home/"$USER" ${COCO_DEV_IMAGE} ${params[@]}
+     docker run -u "$(id -u):$(id -g)" -it --rm -w "$(pwd)" -v /etc/passwd:/etc/passwd -v "$HOME"/..:/home -e HOME=/home/"$USER" "${COCO_DEV_IMAGE}" "${params[@]}"
      ;;
 
    CYGWIN*|MINGW32*|MSYS*)
@@ -27,7 +27,6 @@ case "$(uname -s)" in
    # See correspondence table at the bottom of this answer
 
    *)
-     echo 'Unknown OS not supported' 
+     echo 'Unknown OS not supported'
      ;;
 esac
-
diff --git a/tests/basto6809/HELLO.BAS b/tests/basto6809/HELLO.BAS
new file mode 100644
index 0000000..8a4715c
--- /dev/null
+++ b/tests/basto6809/HELLO.BAS
@@ -0,0 +1,2 @@
+10 PRINT "HELLO COCO"
+20 END
diff --git a/tests/cmoc-os9/hello.c b/tests/cmoc-os9/hello.c
new file mode 100644
index 0000000..e380a7b
--- /dev/null
+++ b/tests/cmoc-os9/hello.c
@@ -0,0 +1,7 @@
+#include <cmoc.h>
+
+int main(void)
+{
+    printf("Hello from OS-9\n");
+    return 0;
+}
diff --git a/tests/java_grinder/Hello.java b/tests/java_grinder/Hello.java
new file mode 100644
index 0000000..7c108a6
--- /dev/null
+++ b/tests/java_grinder/Hello.java
@@ -0,0 +1,8 @@
+import net.mikekohn.java_grinder.TRS80Coco;
+
+public class Hello {
+  public static void main(String[] args) {
+    TRS80Coco.setText(1024, 0x48);
+    TRS80Coco.setText(1025, 0x49);
+  }
+}
diff --git a/tests/mcbasic/MC10HELLO.BAS b/tests/mcbasic/MC10HELLO.BAS
new file mode 100644
index 0000000..9880304
--- /dev/null
+++ b/tests/mcbasic/MC10HELLO.BAS
@@ -0,0 +1,2 @@
+10 PRINT "HELLO MC-10"
+20 END
diff --git a/utils/basto6809todsk b/utils/basto6809todsk
index 148f98d..83c4cca 100755
--- a/utils/basto6809todsk
+++ b/utils/basto6809todsk
@@ -1,27 +1,28 @@
-#!/bin/env bash
+#!/usr/bin/env bash
+set -eu
 
 if [[ $# -ne 1 ]] ; then
-    echo $0 PROG.BAS
-    echo Compiles PROG.BAS into a binary located on PROG.DSK
+    echo "$0 PROG.BAS"
+    echo "Compiles PROG.BAS into a binary located on PROG.DSK"
     exit 0
 fi
 
 BAS_FILE="$1"
-BAS_FILE0=$(basename ${BAS_FILE})
+BAS_FILE0=$(basename "${BAS_FILE}")
 ASM_FILE="${BAS_FILE0%.BAS}.asm"
 BIN_FILE="${BAS_FILE0%.BAS}.BIN"
 DSK_FILE="${BAS_FILE0%.BAS}.DSK"
-CURRENT_DIR="`pwd`"
+CURRENT_DIR="$(pwd)"
 
 # Create a working folder
 tmpdir=$(mktemp -d 2>/dev/null || mktemp -d -t 'tmpdir')
-echo Copying compiler and source file to ${tmpdir}
-cp -R /usr/local/share/basto6809/* ${tmpdir}
-cp $1 ${tmpdir}
-cd ${tmpdir}
+echo "Copying compiler and source file to ${tmpdir}"
+cp -R /usr/local/share/basto6809/* "${tmpdir}"
+cp "$1" "${tmpdir}"
+cd "${tmpdir}"
 
 # Do real work
-echo Compiling ${BAS_FILE} and creating ${ASM_FILE}, ${BIN_FILE} and ${DSK_FILE}
+echo "Compiling ${BAS_FILE} and creating ${ASM_FILE}, ${BIN_FILE} and ${DSK_FILE}"
 ./BasTo6809 "${BAS_FILE0}"
 lwasm  -o "${BIN_FILE}" "$ASM_FILE"
 decb dskini "${DSK_FILE}"