Fix reasoning-model temperature quirk matching and validation

- Omit temperature for OpenRouter's namespaced OpenAI reasoning models
  (openai/o1, openai/o1-mini, openai/o3-mini, openai/o1:online).
- Match o1/o3 only as the bare family name or with a "-" variant, so
  o123 and o3custom keep their temperature.
- Validate the caller's request before clearing temperature, so a
  negative temperature is still a validation error, not a sent request.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/ai/llm/presets/presets.go

@@ -46,14 +46,16 @@ const (
 	KeyNone
 )
 
-// TemperatureRejectingModels is the one list of model-id patterns that
-// reject the temperature field: OpenAI's o1 and o3 reasoning models. A
-// preset whose OmitTemperature holds it never sends a temperature to a
-// matching model.
-var TemperatureRejectingModels = []*regexp.Regexp{
-	regexp.MustCompile(`^o1`),
-	regexp.MustCompile(`^o3`),
-}
+// The reasoning models that reject the temperature field are OpenAI's o1
+// and o3 families: the bare family name or the name followed by a "-"
+// variant (o1, o1-mini, o3-2025-04-16), never a longer word such as o123.
+// OpenRouter names them with an "openai/" prefix and may add a ":" variant
+// (openai/o1:online). A preset whose OmitTemperature holds a pattern never
+// sends a temperature to a matching model.
+var (
+	openAIReasoningModels     = regexp.MustCompile(`^o[13](-.*)?$`)
+	openRouterReasoningModels = regexp.MustCompile(`^openai/o[13]([-:].*)?$`)
+)
 
 // Preset is one vendor's fixed configuration.
 type Preset struct {
@@ -127,7 +129,7 @@ var all = map[string]Preset{
 		Key:               KeyRequired,
 		StructuredOutput:  openai.JSONSchema,
 		StructuredOutputs: []openai.StructuredOutput{openai.JSONSchema},
-		OmitTemperature:   TemperatureRejectingModels,
+		OmitTemperature:   []*regexp.Regexp{openAIReasoningModels},
 	},
 	"openrouter": {
 		Name:                     "openrouter",
@@ -139,6 +141,7 @@ var all = map[string]Preset{
 		StructuredOutput:         openai.JSONSchema,
 		FallbackStructuredOutput: openai.JSONObject,
 		StructuredOutputs:        []openai.StructuredOutput{openai.JSONSchema, openai.JSONObject},
+		OmitTemperature:          []*regexp.Regexp{openRouterReasoningModels},
 	},
 	"ollama": {
 		Name:    "ollama",
@@ -151,7 +154,9 @@ var all = map[string]Preset{
 		Key:               KeyOptional,
 		StructuredOutput:  openai.JSONSchema,
 		StructuredOutputs: []openai.StructuredOutput{openai.JSONSchema, openai.JSONObject, openai.PromptOnly},
-		OmitTemperature:   TemperatureRejectingModels,
+		// The server may be OpenAI itself or a gateway that names models
+		// the OpenRouter way.
+		OmitTemperature: []*regexp.Regexp{openAIReasoningModels, openRouterReasoningModels},
 	},
 }
 
@@ -246,7 +251,13 @@ type configured struct {
 	temperature *float64
 }
 
+// Generate validates req as sent by the caller before changing its
+// temperature, so clearing it for a model that rejects temperature never
+// hides an invalid one.
 func (c *configured) Generate(ctx context.Context, req llm.Request) (llm.Response, error) {
+	if err := req.Validate(); err != nil {
+		return llm.Response{}, fmt.Errorf("presets: generate: %w", err)
+	}
 	if c.temperature == nil {
 		req.Temperature = nil
 	} else if req.Temperature == nil {

internal/ai/llm/presets/presets_test.go

@@ -223,11 +223,19 @@ func TestOpenAICompatiblePreset(t *testing.T) {
 }
 
 func TestTemperatureOmittedForRejectingModels(t *testing.T) {
-	for _, provider := range []string{"openai", "openai_compatible"} {
-		for _, model := range []string{"o1", "o1-mini", "o3-mini"} {
-			s := llm.Settings{Provider: provider, BaseURL: "http://llm.lan/v1", Model: model, Temperature: 0.8}
-			if provider == "openai" {
-				s.BaseURL = ""
+	cases := map[string][]string{
+		"openai":            {"o1", "o1-mini", "o1-2024-12-17", "o3", "o3-mini"},
+		"openai_compatible": {"o1", "o1-mini", "o3-mini", "openai/o1"},
+		"openrouter":        {"openai/o1", "openai/o1-mini", "openai/o3", "openai/o3-mini", "openai/o1:online"},
+	}
+	for provider, models := range cases {
+		for _, model := range models {
+			s := llm.Settings{Provider: provider, Model: model, Temperature: 0.8}
+			switch provider {
+			case "openai_compatible":
+				s.BaseURL = "http://llm.lan/v1"
+			case "openrouter":
+				s.PublicURL = "https://mealquest.example"
 			}
 			for _, req := range []llm.Request{plainRequest(), func() llm.Request { r := plainRequest(); r.Temperature = ptr(0.2); return r }()} {
 				if got, ok := temperature(t, generate(t, s, testKey, req)); ok {
@@ -239,10 +247,19 @@ func TestTemperatureOmittedForRejectingModels(t *testing.T) {
 }
 
 func TestTemperatureSentForOtherModels(t *testing.T) {
-	for _, model := range []string{"gpt-4o", "gpt-4o-mini", "chatgpt-o1-like"} {
-		c := generate(t, llm.Settings{Provider: "openai", Model: model, Temperature: 0.8}, testKey, plainRequest())
-		if got, ok := temperature(t, c); !ok || got != 0.8 {
-			t.Errorf("%s: temperature = %v, %v; want 0.8", model, got, ok)
+	cases := map[string][]string{
+		"openai":     {"gpt-4o", "gpt-4o-mini", "chatgpt-o1-like", "o123", "o3custom", "o1mini", "openai/o1"},
+		"openrouter": {"openai/gpt-4o", "openai/o123", "openai/o3custom", "acme/o1", "o1-mini"},
+	}
+	for provider, models := range cases {
+		for _, model := range models {
+			s := llm.Settings{Provider: provider, Model: model, Temperature: 0.8}
+			if provider == "openrouter" {
+				s.PublicURL = "https://mealquest.example"
+			}
+			if got, ok := temperature(t, generate(t, s, testKey, plainRequest())); !ok || got != 0.8 {
+				t.Errorf("%s %s: temperature = %v, %v; want 0.8", provider, model, got, ok)
+			}
 		}
 	}
 	// A request's own temperature wins over the household's.
@@ -254,8 +271,35 @@ func TestTemperatureSentForOtherModels(t *testing.T) {
 	}
 }
 
+// A request is validated before the temperature quirk clears its
+// temperature, so a negative one is an error and nothing is sent.
+func TestNegativeTemperatureRejectedForRejectingModels(t *testing.T) {
+	rt := &recordingTransport{}
+	orig := http.DefaultTransport
+	http.DefaultTransport = rt
+	t.Cleanup(func() { http.DefaultTransport = orig })
+
+	for _, s := range []llm.Settings{
+		{Provider: "openai", Model: "o1"},
+		{Provider: "openrouter", Model: "openai/o1", PublicURL: "https://mealquest.example"},
+	} {
+		p, err := FromSettings(s, testKey)
+		if err != nil {
+			t.Fatalf("%s: FromSettings: %v", s.Model, err)
+		}
+		req := plainRequest()
+		req.Temperature = ptr(-0.5)
+		if _, err := p.Generate(context.Background(), req); err == nil || errors.Is(err, errStop) || !strings.Contains(err.Error(), "temperature") {
+			t.Errorf("%s: Generate = %v, want a temperature validation error", s.Model, err)
+		}
+	}
+	if len(rt.reqs) != 0 {
+		t.Fatalf("sent %d requests, want 0", len(rt.reqs))
+	}
+}
+
 func TestTemperatureQuirkPresets(t *testing.T) {
-	want := map[string]bool{"openai": true, "openai_compatible": true}
+	want := map[string]bool{"openai": true, "openrouter": true, "openai_compatible": true}
 	for name, p := range all {
 		if got := len(p.OmitTemperature) > 0; got != want[name] {
 			t.Errorf("%s: lists temperature quirk = %v, want %v", name, got, want[name])