Add provider presets and FromSettings factory

internal/ai/llm/presets defines the anthropic, openai, openrouter, ollama
and openai_compatible presets (base URL, adapter, key policy, headers,
structured output modes and model quirks) and FromSettings, which turns
llm.Settings plus the decrypted key into a ready llm.Provider or a typed
configuration error from package llm.

Temperature is omitted for model ids matching ^o1 or ^o3, listed once in
TemperatureRejectingModels.

Maestro task: 4d90a725-5a7c-4bee-bbe4-d036cfb69c5b

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

internal/ai/llm/presets/presets.go

@@ -0,0 +1,257 @@
+// Package presets holds what MealQuest knows about each language-model
+// vendor — base URL, adapter, credentials, headers, structured output mode
+// and model quirks — and FromSettings, which turns the household's
+// llm.Settings into a ready llm.Provider.
+//
+// FromSettings lives here rather than in package llm because it builds the
+// adapters, and every adapter imports llm.
+//
+// Nothing in this package logs, and no error it returns contains the API
+// key or quotes a setting's value.
+package presets
+
+import (
+	"context"
+	"fmt"
+	"math"
+	"regexp"
+	"slices"
+
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/ai/llm"
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/ai/llm/anthropic"
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/ai/llm/ollama"
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/ai/llm/openai"
+)
+
+// Adapter names the llm adapter package a preset builds.
+type Adapter string
+
+// The adapters.
+const (
+	AdapterAnthropic Adapter = "anthropic"
+	AdapterOpenAI    Adapter = "openai"
+	AdapterOllama    Adapter = "ollama"
+)
+
+// KeyPolicy is whether a preset sends an API key.
+type KeyPolicy int
+
+// The key policies.
+const (
+	// KeyRequired presets fail without a key.
+	KeyRequired KeyPolicy = iota
+	// KeyOptional presets send a key when one is given.
+	KeyOptional
+	// KeyNone presets send no key and refuse one.
+	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`),
+}
+
+// Preset is one vendor's fixed configuration.
+type Preset struct {
+	// Name is the Settings.Provider value that selects the preset.
+	Name string
+	// Adapter is the adapter the preset builds.
+	Adapter Adapter
+	// BaseURL is the API root the adapter appends its endpoint paths to.
+	// Empty means the household must supply it in Settings.BaseURL.
+	BaseURL string
+	// Key is whether the preset sends an API key.
+	Key KeyPolicy
+	// RequiresPublicURL means the preset needs Settings.PublicURL for its
+	// headers.
+	RequiresPublicURL bool
+	// Headers returns the extra request headers an openai-adapter preset
+	// sends; nil means none.
+	Headers func(llm.Settings) map[string]string
+	// StructuredOutput is the default mode of an openai-adapter preset.
+	StructuredOutput openai.StructuredOutput
+	// FallbackStructuredOutput is the mode the household can select when
+	// the default fails for its model; empty means none. FromSettings
+	// builds one mode and never retries a request in another.
+	FallbackStructuredOutput openai.StructuredOutput
+	// StructuredOutputs are the modes Settings.StructuredOutput may select.
+	StructuredOutputs []openai.StructuredOutput
+	// MaxTokens is the max_tokens the anthropic adapter sends when a
+	// Request sets none.
+	MaxTokens int
+	// OmitTemperature are model-id patterns the preset never sends a
+	// temperature to.
+	OmitTemperature []*regexp.Regexp
+}
+
+// openRouterHeaders identify MealQuest to OpenRouter: HTTP-Referer is
+// MEALQUEST_PUBLIC_URL and X-Title is the app name.
+func openRouterHeaders(s llm.Settings) map[string]string {
+	return map[string]string{
+		"HTTP-Referer": s.PublicURL,
+		"X-Title":      "MealQuest",
+	}
+}
+
+// omitsTemperature reports whether model matches one of the preset's
+// OmitTemperature patterns.
+func (p Preset) omitsTemperature(model string) bool {
+	return slices.ContainsFunc(p.OmitTemperature, func(re *regexp.Regexp) bool {
+		return re.MatchString(model)
+	})
+}
+
+// Lookup returns the preset Settings.Provider name selects.
+func Lookup(name string) (Preset, bool) {
+	p, ok := all[name]
+	return p, ok
+}
+
+// all is every preset, by Settings.Provider name.
+var all = map[string]Preset{
+	"anthropic": {
+		Name:      "anthropic",
+		Adapter:   AdapterAnthropic,
+		BaseURL:   "https://api.anthropic.com",
+		Key:       KeyRequired,
+		MaxTokens: 4096,
+	},
+	"openai": {
+		Name:              "openai",
+		Adapter:           AdapterOpenAI,
+		BaseURL:           "https://api.openai.com/v1",
+		Key:               KeyRequired,
+		StructuredOutput:  openai.JSONSchema,
+		StructuredOutputs: []openai.StructuredOutput{openai.JSONSchema},
+		OmitTemperature:   TemperatureRejectingModels,
+	},
+	"openrouter": {
+		Name:                     "openrouter",
+		Adapter:                  AdapterOpenAI,
+		BaseURL:                  "https://openrouter.ai/api/v1",
+		Key:                      KeyRequired,
+		RequiresPublicURL:        true,
+		Headers:                  openRouterHeaders,
+		StructuredOutput:         openai.JSONSchema,
+		FallbackStructuredOutput: openai.JSONObject,
+		StructuredOutputs:        []openai.StructuredOutput{openai.JSONSchema, openai.JSONObject},
+	},
+	"ollama": {
+		Name:    "ollama",
+		Adapter: AdapterOllama,
+		Key:     KeyNone,
+	},
+	"openai_compatible": {
+		Name:              "openai_compatible",
+		Adapter:           AdapterOpenAI,
+		Key:               KeyOptional,
+		StructuredOutput:  openai.JSONSchema,
+		StructuredOutputs: []openai.StructuredOutput{openai.JSONSchema, openai.JSONObject, openai.PromptOnly},
+		OmitTemperature:   TemperatureRejectingModels,
+	},
+}
+
+// FromSettings returns the Provider s describes, using key as its API key.
+// It fails with a configuration error from package llm — ErrUnknownProvider,
+// ErrMissingKey, ErrUnexpectedKey, ErrMissingBaseURL, ErrMissingModel,
+// ErrMissingPublicURL or ErrInvalidSetting — before contacting any vendor.
+//
+// The Provider sends s.Temperature with every request whose Temperature is
+// nil; a request that sets one keeps it. Neither is sent to a model the
+// preset's OmitTemperature matches.
+func FromSettings(s llm.Settings, key string) (llm.Provider, error) {
+	p, ok := Lookup(s.Provider)
+	if !ok {
+		return nil, llm.ErrUnknownProvider
+	}
+	if err := check(p, s, key); err != nil {
+		return nil, fmt.Errorf("%s: %w", p.Name, err)
+	}
+	base := p.BaseURL
+	if base == "" {
+		base = s.BaseURL
+	}
+
+	var inner llm.Provider
+	var err error
+	switch p.Adapter {
+	case AdapterAnthropic:
+		inner, err = anthropic.New(anthropic.Config{BaseURL: base, APIKey: key, Model: s.Model, MaxTokens: p.MaxTokens})
+	case AdapterOllama:
+		inner, err = ollama.New(ollama.Config{BaseURL: base, Model: s.Model})
+	case AdapterOpenAI:
+		mode := p.StructuredOutput
+		if s.StructuredOutput != "" {
+			mode = openai.StructuredOutput(s.StructuredOutput)
+		}
+		cfg := openai.Config{BaseURL: base, APIKey: key, Model: s.Model, StructuredOutput: mode}
+		if p.Headers != nil {
+			cfg.Headers = p.Headers(s)
+		}
+		inner, err = openai.New(cfg)
+	default:
+		panic("presets: preset " + p.Name + " has unknown adapter " + string(p.Adapter))
+	}
+	if err != nil {
+		return nil, fmt.Errorf("%s: %w: %w", p.Name, llm.ErrInvalidSetting, err)
+	}
+
+	cp := &configured{Provider: inner}
+	if !p.omitsTemperature(s.Model) {
+		t := s.Temperature
+		cp.temperature = &t
+	}
+	return cp, nil
+}
+
+// check validates s and key against p. Its errors never quote a value.
+func check(p Preset, s llm.Settings, key string) error {
+	switch {
+	case p.Key == KeyRequired && key == "":
+		return llm.ErrMissingKey
+	case p.Key == KeyNone && key != "":
+		return llm.ErrUnexpectedKey
+	}
+	switch {
+	case p.BaseURL == "" && s.BaseURL == "":
+		return llm.ErrMissingBaseURL
+	case p.BaseURL != "" && s.BaseURL != "" && s.BaseURL != p.BaseURL:
+		return fmt.Errorf("%w: base URL is fixed by the preset", llm.ErrInvalidSetting)
+	}
+	if s.Model == "" {
+		return llm.ErrMissingModel
+	}
+	if p.RequiresPublicURL && s.PublicURL == "" {
+		return llm.ErrMissingPublicURL
+	}
+	if s.StructuredOutput != "" && !slices.Contains(p.StructuredOutputs, openai.StructuredOutput(s.StructuredOutput)) {
+		return fmt.Errorf("%w: structured output mode is not supported by the preset", llm.ErrInvalidSetting)
+	}
+	if math.IsNaN(s.Temperature) || math.IsInf(s.Temperature, 0) || s.Temperature < 0 {
+		return fmt.Errorf("%w: temperature must be a non-negative number", llm.ErrInvalidSetting)
+	}
+	return nil
+}
+
+// configured applies the household temperature and the preset's
+// temperature quirk to every Generate.
+type configured struct {
+	llm.Provider
+	// temperature is sent when a request sets none; nil means the model
+	// rejects temperature, so none is ever sent.
+	temperature *float64
+}
+
+func (c *configured) Generate(ctx context.Context, req llm.Request) (llm.Response, error) {
+	if c.temperature == nil {
+		req.Temperature = nil
+	} else if req.Temperature == nil {
+		t := *c.temperature
+		req.Temperature = &t
+	}
+	return c.Provider.Generate(ctx, req)
+}

internal/ai/llm/presets/presets_test.go

@@ -0,0 +1,357 @@
+package presets
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"io"
+	"net/http"
+	"strings"
+	"testing"
+
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/ai/llm"
+)
+
+const testKey = "sk-test-0123456789"
+
+// captured is the HTTP request an adapter sent.
+type captured struct {
+	url    string
+	header http.Header
+	body   map[string]json.RawMessage
+}
+
+var errStop = errors.New("recorded")
+
+// recordingTransport records each request and fails it, so no request
+// leaves the process.
+type recordingTransport struct{ reqs []captured }
+
+func (rt *recordingTransport) RoundTrip(r *http.Request) (*http.Response, error) {
+	c := captured{url: r.URL.String(), header: r.Header.Clone()}
+	if r.Body != nil {
+		raw, err := io.ReadAll(r.Body)
+		if err != nil {
+			return nil, err
+		}
+		if err := json.Unmarshal(raw, &c.body); err != nil {
+			return nil, err
+		}
+	}
+	rt.reqs = append(rt.reqs, c)
+	return nil, errStop
+}
+
+// generate builds the provider s describes and returns the request its
+// Generate sends for req. The adapters use http.DefaultTransport, which the
+// test replaces, so the real preset base URLs are never contacted.
+func generate(t *testing.T, s llm.Settings, key string, req llm.Request) captured {
+	t.Helper()
+	rt := &recordingTransport{}
+	orig := http.DefaultTransport
+	http.DefaultTransport = rt
+	t.Cleanup(func() { http.DefaultTransport = orig })
+
+	p, err := FromSettings(s, key)
+	if err != nil {
+		t.Fatalf("FromSettings: %v", err)
+	}
+	if _, err := p.Generate(context.Background(), req); err == nil {
+		t.Fatal("Generate succeeded through the recording transport")
+	}
+	if len(rt.reqs) != 1 {
+		t.Fatalf("sent %d requests, want 1", len(rt.reqs))
+	}
+	return rt.reqs[0]
+}
+
+func plainRequest() llm.Request {
+	return llm.Request{Messages: []llm.Message{{Role: llm.RoleUser, Content: "dinner?"}}}
+}
+
+func schemaRequest() llm.Request {
+	r := plainRequest()
+	r.Schema = &llm.JSONSchema{Name: "side_quests", Schema: json.RawMessage(`{"type":"object"}`)}
+	return r
+}
+
+func ptr(f float64) *float64 { return &f }
+
+func responseFormatType(t *testing.T, c captured) string {
+	t.Helper()
+	raw, ok := c.body["response_format"]
+	if !ok {
+		return ""
+	}
+	var rf struct{ Type string }
+	if err := json.Unmarshal(raw, &rf); err != nil {
+		t.Fatalf("response_format: %v", err)
+	}
+	return rf.Type
+}
+
+func temperature(t *testing.T, c captured) (float64, bool) {
+	t.Helper()
+	raw, ok := c.body["temperature"]
+	if !ok {
+		return 0, false
+	}
+	var f float64
+	if err := json.Unmarshal(raw, &f); err != nil {
+		t.Fatalf("temperature: %v", err)
+	}
+	return f, true
+}
+
+func TestAnthropicPreset(t *testing.T) {
+	c := generate(t, llm.Settings{Provider: "anthropic", Model: "claude-sonnet-5", Temperature: 0.7}, testKey, plainRequest())
+	if c.url != "https://api.anthropic.com/v1/messages" {
+		t.Fatalf("URL = %q", c.url)
+	}
+	if got := c.header.Get("X-Api-Key"); got != testKey {
+		t.Fatalf("x-api-key = %q", got)
+	}
+	if got := c.header.Get("Authorization"); got != "" {
+		t.Fatalf("Authorization = %q, want none", got)
+	}
+	if got, ok := temperature(t, c); !ok || got != 0.7 {
+		t.Fatalf("temperature = %v, %v; want 0.7", got, ok)
+	}
+	if string(c.body["max_tokens"]) != "4096" {
+		t.Fatalf("max_tokens = %s", c.body["max_tokens"])
+	}
+}
+
+func TestAnthropicPresetAcceptsItsOwnBaseURL(t *testing.T) {
+	c := generate(t, llm.Settings{Provider: "anthropic", BaseURL: "https://api.anthropic.com", Model: "claude-sonnet-5"}, testKey, plainRequest())
+	if c.url != "https://api.anthropic.com/v1/messages" {
+		t.Fatalf("URL = %q", c.url)
+	}
+}
+
+func TestOpenAIPreset(t *testing.T) {
+	c := generate(t, llm.Settings{Provider: "openai", Model: "gpt-4o", Temperature: 0.4}, testKey, schemaRequest())
+	if c.url != "https://api.openai.com/v1/chat/completions" {
+		t.Fatalf("URL = %q", c.url)
+	}
+	if got := c.header.Get("Authorization"); got != "Bearer "+testKey {
+		t.Fatalf("Authorization = %q", got)
+	}
+	if got := responseFormatType(t, c); got != "json_schema" {
+		t.Fatalf("response_format type = %q, want json_schema", got)
+	}
+	if c.header.Get("HTTP-Referer") != "" || c.header.Get("X-Title") != "" {
+		t.Fatal("openai sends OpenRouter headers")
+	}
+}
+
+func TestOpenRouterPreset(t *testing.T) {
+	s := llm.Settings{Provider: "openrouter", Model: "openai/gpt-4o", PublicURL: "https://meals.example.com/"}
+	c := generate(t, s, testKey, schemaRequest())
+	if c.url != "https://openrouter.ai/api/v1/chat/completions" {
+		t.Fatalf("URL = %q", c.url)
+	}
+	if got := c.header.Get("Authorization"); got != "Bearer "+testKey {
+		t.Fatalf("Authorization = %q", got)
+	}
+	if got := c.header.Get("HTTP-Referer"); got != "https://meals.example.com/" {
+		t.Fatalf("HTTP-Referer = %q", got)
+	}
+	if got := c.header.Get("X-Title"); got != "MealQuest" {
+		t.Fatalf("X-Title = %q", got)
+	}
+	if got := responseFormatType(t, c); got != "json_schema" {
+		t.Fatalf("default response_format type = %q, want json_schema", got)
+	}
+}
+
+func TestOpenRouterFallbackModeIsJSONObject(t *testing.T) {
+	p, _ := Lookup("openrouter")
+	s := llm.Settings{
+		Provider:         "openrouter",
+		Model:            "meta-llama/llama-3.3-70b-instruct",
+		PublicURL:        "https://meals.example.com",
+		StructuredOutput: string(p.FallbackStructuredOutput),
+	}
+	c := generate(t, s, testKey, schemaRequest())
+	if got := responseFormatType(t, c); got != "json_object" {
+		t.Fatalf("response_format type = %q, want json_object", got)
+	}
+}
+
+func TestOllamaPreset(t *testing.T) {
+	s := llm.Settings{Provider: "ollama", BaseURL: "http://ollama.lan:11434", Model: "llama3.2", Temperature: 0.5}
+	c := generate(t, s, "", plainRequest())
+	if c.url != "http://ollama.lan:11434/api/chat" {
+		t.Fatalf("URL = %q", c.url)
+	}
+	if got := c.header.Get("Authorization"); got != "" {
+		t.Fatalf("Authorization = %q, want none", got)
+	}
+	var opts struct{ Temperature *float64 }
+	if err := json.Unmarshal(c.body["options"], &opts); err != nil || opts.Temperature == nil || *opts.Temperature != 0.5 {
+		t.Fatalf("options = %s", c.body["options"])
+	}
+}
+
+func TestOpenAICompatiblePreset(t *testing.T) {
+	base := llm.Settings{Provider: "openai_compatible", BaseURL: "http://llm.lan:8000/v1", Model: "qwen2.5"}
+
+	c := generate(t, base, "", schemaRequest())
+	if c.url != "http://llm.lan:8000/v1/chat/completions" {
+		t.Fatalf("URL = %q", c.url)
+	}
+	if got := c.header.Get("Authorization"); got != "" {
+		t.Fatalf("Authorization without key = %q, want none", got)
+	}
+	if got := responseFormatType(t, c); got != "json_schema" {
+		t.Fatalf("default response_format type = %q, want json_schema", got)
+	}
+
+	c = generate(t, base, testKey, plainRequest())
+	if got := c.header.Get("Authorization"); got != "Bearer "+testKey {
+		t.Fatalf("Authorization with key = %q", got)
+	}
+
+	for mode, want := range map[string]string{"json_schema": "json_schema", "json_object": "json_object", "prompt_only": ""} {
+		s := base
+		s.StructuredOutput = mode
+		if got := responseFormatType(t, generate(t, s, "", schemaRequest())); got != want {
+			t.Errorf("mode %s: response_format type = %q, want %q", mode, got, want)
+		}
+	}
+}
+
+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 = ""
+			}
+			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 {
+					t.Errorf("%s %s: temperature %v sent, want omitted", provider, model, got)
+				}
+			}
+		}
+	}
+}
+
+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)
+		}
+	}
+	// A request's own temperature wins over the household's.
+	req := plainRequest()
+	req.Temperature = ptr(0.1)
+	c := generate(t, llm.Settings{Provider: "openai", Model: "gpt-4o", Temperature: 0.8}, testKey, req)
+	if got, ok := temperature(t, c); !ok || got != 0.1 {
+		t.Fatalf("temperature = %v, %v; want 0.1", got, ok)
+	}
+}
+
+func TestTemperatureQuirkPresets(t *testing.T) {
+	want := map[string]bool{"openai": 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])
+		}
+	}
+}
+
+func TestPresetTable(t *testing.T) {
+	cases := []struct {
+		name    string
+		adapter Adapter
+		baseURL string
+		key     KeyPolicy
+	}{
+		{"anthropic", AdapterAnthropic, "https://api.anthropic.com", KeyRequired},
+		{"openai", AdapterOpenAI, "https://api.openai.com/v1", KeyRequired},
+		{"openrouter", AdapterOpenAI, "https://openrouter.ai/api/v1", KeyRequired},
+		{"ollama", AdapterOllama, "", KeyNone},
+		{"openai_compatible", AdapterOpenAI, "", KeyOptional},
+	}
+	if len(all) != len(cases) {
+		t.Fatalf("%d presets, want %d", len(all), len(cases))
+	}
+	for _, c := range cases {
+		p, ok := Lookup(c.name)
+		if !ok {
+			t.Fatalf("no preset %q", c.name)
+		}
+		if p.Name != c.name || p.Adapter != c.adapter || p.BaseURL != c.baseURL || p.Key != c.key {
+			t.Errorf("%s = {%s %s %q %d}", c.name, p.Name, p.Adapter, p.BaseURL, p.Key)
+		}
+	}
+}
+
+func TestConfigErrors(t *testing.T) {
+	sentinels := []error{
+		llm.ErrUnknownProvider, llm.ErrMissingKey, llm.ErrUnexpectedKey, llm.ErrMissingBaseURL,
+		llm.ErrMissingModel, llm.ErrMissingPublicURL, llm.ErrInvalidSetting,
+	}
+	cases := []struct {
+		name string
+		s    llm.Settings
+		key  string
+		want error
+	}{
+		{"unknown provider", llm.Settings{Provider: "gemini", Model: "m"}, testKey, llm.ErrUnknownProvider},
+		{"anthropic no key", llm.Settings{Provider: "anthropic", Model: "m"}, "", llm.ErrMissingKey},
+		{"openai no key", llm.Settings{Provider: "openai", Model: "m"}, "", llm.ErrMissingKey},
+		{"openrouter no key", llm.Settings{Provider: "openrouter", Model: "m", PublicURL: "https://x.example"}, "", llm.ErrMissingKey},
+		{"ollama with key", llm.Settings{Provider: "ollama", BaseURL: "http://o:11434", Model: "m"}, testKey, llm.ErrUnexpectedKey},
+		{"ollama no base URL", llm.Settings{Provider: "ollama", Model: "m"}, "", llm.ErrMissingBaseURL},
+		{"openai_compatible no base URL", llm.Settings{Provider: "openai_compatible", Model: "m"}, "", llm.ErrMissingBaseURL},
+		{"anthropic no model", llm.Settings{Provider: "anthropic"}, testKey, llm.ErrMissingModel},
+		{"openai no model", llm.Settings{Provider: "openai"}, testKey, llm.ErrMissingModel},
+		{"openrouter no model", llm.Settings{Provider: "openrouter", PublicURL: "https://x.example"}, testKey, llm.ErrMissingModel},
+		{"ollama no model", llm.Settings{Provider: "ollama", BaseURL: "http://o:11434"}, "", llm.ErrMissingModel},
+		{"openai_compatible no model", llm.Settings{Provider: "openai_compatible", BaseURL: "http://l/v1"}, "", llm.ErrMissingModel},
+		{"openrouter no public URL", llm.Settings{Provider: "openrouter", Model: "m"}, testKey, llm.ErrMissingPublicURL},
+		{"fixed base URL overridden", llm.Settings{Provider: "openai", BaseURL: "https://evil.example/v1", Model: "m"}, testKey, llm.ErrInvalidSetting},
+		{"openai json_object", llm.Settings{Provider: "openai", Model: "m", StructuredOutput: "json_object"}, testKey, llm.ErrInvalidSetting},
+		{"anthropic mode", llm.Settings{Provider: "anthropic", Model: "m", StructuredOutput: "json_schema"}, testKey, llm.ErrInvalidSetting},
+		{"unknown mode", llm.Settings{Provider: "openai_compatible", BaseURL: "http://l/v1", Model: "m", StructuredOutput: "xml"}, "", llm.ErrInvalidSetting},
+		{"negative temperature", llm.Settings{Provider: "openai", Model: "m", Temperature: -0.1}, testKey, llm.ErrInvalidSetting},
+		{"bad base URL", llm.Settings{Provider: "ollama", BaseURL: "ftp://o", Model: "m"}, "", llm.ErrInvalidSetting},
+	}
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			p, err := FromSettings(c.s, c.key)
+			if p != nil || !errors.Is(err, c.want) {
+				t.Fatalf("FromSettings = %v, %v; want %v", p, err, c.want)
+			}
+			for _, other := range sentinels {
+				if other != c.want && errors.Is(err, other) {
+					t.Fatalf("error %v also matches %v", err, other)
+				}
+			}
+			if c.key != "" && strings.Contains(err.Error(), c.key) {
+				t.Fatalf("error leaks the key: %v", err)
+			}
+		})
+	}
+}
+
+func TestReadyProviderForEveryPreset(t *testing.T) {
+	for _, s := range []struct {
+		s   llm.Settings
+		key string
+	}{
+		{llm.Settings{Provider: "anthropic", Model: "m"}, testKey},
+		{llm.Settings{Provider: "openai", Model: "m"}, testKey},
+		{llm.Settings{Provider: "openrouter", Model: "m", PublicURL: "https://x.example"}, testKey},
+		{llm.Settings{Provider: "ollama", BaseURL: "http://o:11434", Model: "m"}, ""},
+		{llm.Settings{Provider: "openai_compatible", BaseURL: "http://l/v1", Model: "m"}, ""},
+	} {
+		if p, err := FromSettings(s.s, s.key); err != nil || p == nil {
+			t.Errorf("%s: FromSettings = %v, %v", s.s.Provider, p, err)
+		}
+	}
+}

internal/ai/llm/settings.go

@@ -0,0 +1,65 @@
+package llm
+
+import "errors"
+
+// Settings is the household's AI configuration, the input to
+// presets.FromSettings. The caller fills it from the db.AiSetting row and
+// the service config; this package does not import internal/db.
+//
+//	llm.Settings{
+//		Provider:    row.Provider,
+//		BaseURL:     row.BaseUrl,
+//		Model:       row.Model,
+//		Temperature: row.Temperature,
+//		PublicURL:   cfg.PublicURL.String(), // MEALQUEST_PUBLIC_URL
+//	}
+//
+// Settings never holds the API key: the caller decrypts it and passes it
+// to presets.FromSettings separately.
+type Settings struct {
+	// Provider names the preset: "anthropic", "openai", "openrouter",
+	// "ollama" or "openai_compatible".
+	Provider string
+	// BaseURL is the API root. It is required for ollama and
+	// openai_compatible; the other presets fix their own, and a non-empty
+	// value must equal it.
+	BaseURL string
+	// Model is the model id Generate requests. It is required.
+	Model string
+	// Temperature is the household's sampling temperature. It is sent with
+	// every request that sets none, except to models that reject it.
+	Temperature float64
+	// PublicURL is MEALQUEST_PUBLIC_URL. OpenRouter requires it and
+	// receives it as the HTTP-Referer header; other presets ignore it.
+	PublicURL string
+	// StructuredOutput selects how an OpenAI-compatible preset asks for
+	// JSON: "json_schema", "json_object" or "prompt_only". Empty selects
+	// the preset's default, json_schema. Each preset allows only the modes
+	// it lists; anthropic and ollama allow none, so it must be empty.
+	StructuredOutput string
+}
+
+// Configuration errors from presets.FromSettings. Each is distinct and
+// matches with errors.Is.
+var (
+	// ErrUnknownProvider means Settings.Provider names no preset.
+	ErrUnknownProvider = errors.New("llm: unknown provider")
+	// ErrMissingKey means the preset requires an API key and none was
+	// given.
+	ErrMissingKey = errors.New("llm: API key is required")
+	// ErrUnexpectedKey means an API key was given to a preset that sends
+	// none.
+	ErrUnexpectedKey = errors.New("llm: provider takes no API key")
+	// ErrMissingBaseURL means the preset requires a base URL and none was
+	// given.
+	ErrMissingBaseURL = errors.New("llm: base URL is required")
+	// ErrMissingModel means Settings.Model is empty.
+	ErrMissingModel = errors.New("llm: model is required")
+	// ErrMissingPublicURL means the preset requires Settings.PublicURL and
+	// it is empty.
+	ErrMissingPublicURL = errors.New("llm: public URL is required")
+	// ErrInvalidSetting means a setting has a value the preset does not
+	// accept, such as a base URL other than the preset's, an unsupported
+	// structured output mode or a negative temperature.
+	ErrInvalidSetting = errors.New("llm: invalid setting")
+)