Providers: strip Gemma 4 reasoning leak (#933)

internal/providers/reasoning_resolution.go

@@ -32,9 +32,13 @@ func modelLeaksReasoning(model string) bool {
 	if m == "" {
 		return false
 	}
-	// Known leakers: Moonshot Kimi (any variant), DeepSeek-Reasoner family.
+	// Known leakers: Moonshot Kimi (any variant), DeepSeek-Reasoner family,
+	// and Gemma 4+ variants (for example "gemma4:8b" or "google/gemma-4-27b-it").
 	// Extend this list only after confirming the model does not honor effort="off".
-	return strings.Contains(m, "kimi") || strings.Contains(m, "deepseek-reasoner")
+	return strings.Contains(m, "kimi") ||
+		strings.Contains(m, "deepseek-reasoner") ||
+		strings.Contains(m, "gemma4") ||
+		strings.Contains(m, "gemma-4")
 }
 
 func ResolveReasoningDecision(provider Provider, model, requestedEffort, fallback, source string) (out ReasoningDecision) {

internal/providers/reasoning_strip_test.go

@@ -17,6 +17,7 @@ func TestResolveReasoningDecisionStripsForLeakyModels(t *testing.T) {
 		{"kimi k2 default off", "kimi-k2", true, "off"},
 		{"kimi thinking preview", "moonshot/kimi-k2-thinking", true, "off"},
 		{"deepseek reasoner", "deepseek-reasoner", true, "off"},
+		{"gemma 4 family", "google/gemma-4-27b-it", true, "off"},
 		{"deepseek chat not flagged", "deepseek-chat", false, "off"},
 		{"gpt-5.4 not flagged", "gpt-5.4", false, "off"},
 		{"empty model", "", false, "off"},
@@ -52,7 +53,7 @@ func TestResolveReasoningDecisionNoStripWhenEffortActive(t *testing.T) {
 
 // TestModelLeaksReasoning spot-checks the model allowlist directly.
 func TestModelLeaksReasoning(t *testing.T) {
-	leaky := []string{"kimi-k2", "KIMI-K2-Thinking", "deepseek-reasoner"}
+	leaky := []string{"kimi-k2", "KIMI-K2-Thinking", "deepseek-reasoner", "google/gemma-4-27b-it", "gemma4:8b-it-q4_K_M"}
 	for _, m := range leaky {
 		if !modelLeaksReasoning(m) {
 			t.Errorf("modelLeaksReasoning(%q) = false, want true", m)