diff --git a/helm/tools/grafana-mcp/templates/_helpers.tpl b/helm/tools/grafana-mcp/templates/_helpers.tpl
index 5a8d2bb30f..bd074a815c 100644
--- a/helm/tools/grafana-mcp/templates/_helpers.tpl
+++ b/helm/tools/grafana-mcp/templates/_helpers.tpl
@@ -67,3 +67,12 @@ Create the grafana server URL
 {{- define "grafana-mcp.serverUrl" -}}
 {{- printf "http://%s.%s:%d/mcp" (include "grafana-mcp.fullname" .) .Release.Namespace (.Values.service.port | int) }}
 {{- end }}
+
+{{/*
+Join registry/repository for grafana-mcp image, skipping empty segments, then append tag
+*/}}
+{{- define "grafana-mcp.image" -}}
+{{- $img := .Values.image -}}
+{{- $parts := compact (list $img.registry $img.repository) -}}
+{{- printf "%s:%s" (join "/" $parts) $img.tag -}}
+{{- end -}}
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diff --git a/helm/tools/grafana-mcp/templates/deployment.yaml b/helm/tools/grafana-mcp/templates/deployment.yaml
index e2a99b0460..bf3be83f36 100644
--- a/helm/tools/grafana-mcp/templates/deployment.yaml
+++ b/helm/tools/grafana-mcp/templates/deployment.yaml
@@ -35,7 +35,7 @@ spec:
         - name: grafana-mcp
           securityContext:
             {{- toYaml .Values.securityContext | nindent 12 }}
-          image: "{{ .Values.image.registry }}/{{ .Values.image.repository }}:{{ .Values.image.tag }}" 
+          image: {{ include "grafana-mcp.image" . }}
           imagePullPolicy: {{ .Values.image.pullPolicy | default "IfNotPresent" }}
           args:
             - --transport
diff --git a/helm/tools/grafana-mcp/tests/deployment_test.yaml b/helm/tools/grafana-mcp/tests/deployment_test.yaml
index b01bdd4ea2..d1ed1c4add 100644
--- a/helm/tools/grafana-mcp/tests/deployment_test.yaml
+++ b/helm/tools/grafana-mcp/tests/deployment_test.yaml
@@ -100,3 +100,23 @@ tests:
       - equal:
           path: spec.template.spec.containers[0].securityContext.runAsUser
           value: 1000
+
+  - it: should render the default container image
+    template: deployment.yaml
+    asserts:
+      - equal:
+          path: spec.template.spec.containers[0].image
+          value: mcp/grafana:latest
+
+  - it: should omit empty registry segment in image
+    template: deployment.yaml
+    set:
+      image:
+        registry: ""
+    asserts:
+      - equal:
+          path: spec.template.spec.containers[0].image
+          value: grafana:latest
+      - notMatchRegex:
+          path: spec.template.spec.containers[0].image
+          pattern: "^/"          # no leading slash
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