diff --git a/core/services/nodes/registry.go b/core/services/nodes/registry.go
index d6fd59662..1e5d52db0 100644
--- a/core/services/nodes/registry.go
+++ b/core/services/nodes/registry.go
@@ -1159,11 +1159,28 @@ func requireCurrentRevision(tx *gorm.DB, modelName, revision string) error {
 		return err
 	}
 	if state.ConfigRevision != revision {
-		return ErrStaleModelConfigRevision
+		// Name both sides. "stale model config revision" on its own says only
+		// that two hashes differ, which leaves an operator no way to tell an
+		// edited configuration from a revision that is not reproducible for one
+		// unchanged file.
+		return fmt.Errorf("%w (request carries %s, controller holds %s)",
+			ErrStaleModelConfigRevision, shortRevision(revision), shortRevision(state.ConfigRevision))
 	}
 	return nil
 }
 
+// shortRevision trims a revision for log and error output. The full value is a
+// sha256 hex digest; the leading bytes identify it well enough to compare two.
+func shortRevision(revision string) string {
+	if revision == "" {
+		return "(none)"
+	}
+	if len(revision) > 12 {
+		return revision[:12]
+	}
+	return revision
+}
+
 func validateRevisionWrite(modelName, revision string, revisionRequired bool) error {
 	if modelName == "" {
 		return fmt.Errorf("model name is required")
diff --git a/core/services/nodes/revision_error_detail_test.go b/core/services/nodes/revision_error_detail_test.go
new file mode 100644
index 000000000..25be6866a
--- /dev/null
+++ b/core/services/nodes/revision_error_detail_test.go
@@ -0,0 +1,24 @@
+package nodes
+
+import (
+	"errors"
+	"fmt"
+
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("Stale revision error detail", func() {
+	It("keeps errors.Is matching so callers can still classify it", func() {
+		err := fmt.Errorf("%w (request carries %s, controller holds %s)",
+			ErrStaleModelConfigRevision, shortRevision("aaaabbbbccccdddd"), shortRevision("1111222233334444"))
+		Expect(errors.Is(err, ErrStaleModelConfigRevision)).To(BeTrue())
+		Expect(err.Error()).To(ContainSubstring("stale model config revision"))
+	})
+
+	It("names both revisions so an operator can tell which side moved", func() {
+		Expect(shortRevision("aaaabbbbccccdddd")).To(Equal("aaaabbbbcccc"))
+		Expect(shortRevision("short")).To(Equal("short"))
+		Expect(shortRevision("")).To(Equal("(none)"))
+	})
+})