diff --git a/Makefile b/Makefile
index c7d0a29..b72bb19 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
 CHAINSAW ?= chainsaw
 
 TEST_DIR := tests
-VALUES ?= infra/kind/values-basic-go.yaml
+VALUES ?=
 ASSERT_TIMEOUT ?= 15m
 CHAINSAW_EXTRA_FLAGS ?=
 
@@ -23,7 +23,7 @@ help: ## Show available targets
 	@echo "test framework targets:"
 	@echo ""
 	@echo "  tests:"
-	@echo "    * values via VALUES (default infra/kind/values-basic-go.yaml)"
+	@echo "    * values via VALUES (required; e.g. VALUES=../metal-lab/values-containerlab-node1.yaml)"
 	@echo "    * assert timeout via ASSERT_TIMEOUT (default 15m; e.g. ASSERT_TIMEOUT=5m)"
 	@echo "    * extra chainsaw flags via CHAINSAW_EXTRA_FLAGS (e.g. CHAINSAW_EXTRA_FLAGS=\"--skip-delete -v\")"
 	@echo ""
@@ -39,10 +39,19 @@ help: ## Show available targets
 	@echo "    test/09-persistent-boot-order    (persistent boot order)"
 	@echo ""
 
+.PHONY: require-values
+require-values:
+	@test -n "$(VALUES)" || { \
+		echo "VALUES is not set. Pass a chainsaw values file, e.g."; \
+		echo "  make $(MAKECMDGOALS) VALUES=/path/to/values.yaml"; \
+		echo "See README.md for the expected contents."; \
+		exit 1; \
+	}
+
 .PHONY: test $(addprefix test/,$(TESTS))
 
-test: ## Run every test
+test: require-values ## Run every test
 	$(CHAINSAW_RUN) $(addprefix $(TEST_DIR)/,$(TESTS))
 
-$(addprefix test/,$(TESTS)): test/%: ## Run a single test
+$(addprefix test/,$(TESTS)): test/%: require-values ## Run a single test
 	$(CHAINSAW_RUN) $(TEST_DIR)/$*
diff --git a/README.md b/README.md
index 8e98f7c..26bc323 100644
--- a/README.md
+++ b/README.md
@@ -13,12 +13,12 @@ The `tests` directory contains a suite of tests based on [chainsaw](https://kyve
 * A metal-operator installation and BMC to run tests against. This repository usually uses the locally virtualised [metal-lab](https://github.com/simontesar/metal-lab) to develop or verify functionality of the actual tests. You can use the lab setup as a reference.
 
 ### Usage
-The server to run a test against is configured by passing a values file to chainsaw. The default file is `infra/kind/values-basic-go.yaml` which points to a Redfish mock setup in the [`kind` environment](environments.md) and should be overridden via `VALUES`.
+The server to run a test against is configured by passing a values file to chainsaw via `VALUES`. There is no default, tests fail unless `VALUES` is set. To just see the suite run, use `infra/kind/values-basic-go.yaml`, which points to a Redfish mock setup in the [`kind` environment](environments.md).
 
 ```bash
 # Examples
-make test                                                                              # Run all tests
-make test/01-bmc-registration                                                          # Run a specific test
+make test VALUES=infra/kind/values-basic-go.yaml                                       # Run all tests
+make test/01-bmc-registration VALUES=infra/kind/values-basic-go.yaml                   # Run a specific test
 make test/03-power-annotation VALUES=/path/to/metal-lab/values-containerlab-node1.yaml # Run against a specific BMC
 ```