diff --git a/internal/adapters/llm/temperature_test.go b/internal/adapters/llm/temperature_test.go
new file mode 100644
index 0000000..7a227e7
--- /dev/null
+++ b/internal/adapters/llm/temperature_test.go
@@ -0,0 +1,57 @@
+package llm
+
+import (
+	"context"
+	"encoding/json"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+)
+
+// capturedTemperature runs one Complete against a fake gateway and returns the
+// "temperature" field the request carried, and whether it was present at all.
+func capturedTemperature(t *testing.T, opts ...Option) (float64, bool) {
+	t.Helper()
+	var body map[string]any
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		raw, _ := io.ReadAll(r.Body)
+		_ = json.Unmarshal(raw, &body)
+		w.Header().Set("Content-Type", "application/json")
+		_ = json.NewEncoder(w).Encode(map[string]any{"choices": []map[string]any{{"message": map[string]any{"role": "assistant", "content": "ok"}}}})
+	}))
+	defer srv.Close()
+
+	if _, err := New(srv.URL, "", "m", 5*time.Second, opts...).Complete(context.Background(), "s", "u"); err != nil {
+		t.Fatalf("Complete: %v", err)
+	}
+	v, ok := body["temperature"].(float64)
+	return v, ok
+}
+
+func TestClient_DefaultTemperatureIsUnchanged(t *testing.T) {
+	got, ok := capturedTemperature(t)
+
+	if !ok || got != 0.2 {
+		t.Fatalf("default temperature = %v (present %v), want 0.2: existing callers must not change behaviour", got, ok)
+	}
+}
+
+func TestClient_WithTemperatureZeroSendsExactlyZero(t *testing.T) {
+	// The reconciler's accuracy (92%/97%) was measured at temperature 0. Zero must be
+	// SENT, not treated as "unset" and replaced by the default.
+	got, ok := capturedTemperature(t, WithTemperature(0))
+
+	if !ok || got != 0 {
+		t.Fatalf("temperature = %v (present %v), want an explicit 0", got, ok)
+	}
+}
+
+func TestClient_WithTemperatureSendsTheGivenValue(t *testing.T) {
+	got, ok := capturedTemperature(t, WithTemperature(0.7))
+
+	if !ok || got != 0.7 {
+		t.Fatalf("temperature = %v (present %v), want 0.7", got, ok)
+	}
+}