Validate and compose provider endpoints

internal/backend/registry.go

@@ -5,7 +5,6 @@ package backend
 import (
 	"errors"
 	"fmt"
-	"net/url"
 	"regexp"
 	"sort"
 	"strings"
@@ -109,10 +108,11 @@ func (r *Registry) CapacityPolicies() map[string]domain.BackendCapacityPolicy {
 }
 
 func normalizeBackend(definition domain.Backend) (domain.Backend, error) {
-	definition.Endpoint = strings.TrimSpace(definition.Endpoint)
-	if err := validateEndpoint(definition.Endpoint); err != nil {
+	endpoint, err := domain.NormalizeOpenAICompatibleBaseEndpoint(definition.Endpoint)
+	if err != nil {
 		return domain.Backend{}, fmt.Errorf("backend %q endpoint: %w", definition.ID, err)
 	}
+	definition.Endpoint = endpoint
 
 	definition.APIKeyEnv = strings.TrimSpace(definition.APIKeyEnv)
 	if definition.APIKeyEnv != "" && !environmentVariableName.MatchString(definition.APIKeyEnv) {
@@ -182,31 +182,3 @@ func normalizeBackend(definition domain.Backend) (domain.Backend, error) {
 	definition.ExtraParams = extraParams
 	return definition, nil
 }
-
-func validateEndpoint(endpoint string) error {
-	if endpoint == "" {
-		return errors.New("must not be blank")
-	}
-	if strings.Contains(endpoint, "#") {
-		return errors.New("must not contain a fragment")
-	}
-
-	parsed, err := url.Parse(endpoint)
-	if err != nil {
-		return fmt.Errorf("must be a valid URL: %w", err)
-	}
-	scheme := strings.ToLower(parsed.Scheme)
-	if scheme != "http" && scheme != "https" {
-		return errors.New("must use http or https")
-	}
-	if !parsed.IsAbs() || parsed.Hostname() == "" {
-		return errors.New("must be absolute and include a host")
-	}
-	if parsed.User != nil {
-		return errors.New("must not contain user information")
-	}
-	if parsed.RawQuery != "" || parsed.ForceQuery {
-		return errors.New("must not contain a query string")
-	}
-	return nil
-}

internal/domain/endpoint.go

@@ -0,0 +1,39 @@
+package domain
+
+import (
+	"errors"
+	"net/url"
+	"strings"
+)
+
+// NormalizeOpenAICompatibleBaseEndpoint trims and validates a source-neutral
+// OpenAI-compatible provider base endpoint.
+func NormalizeOpenAICompatibleBaseEndpoint(endpoint string) (string, error) {
+	endpoint = strings.TrimSpace(endpoint)
+	if endpoint == "" {
+		return "", errors.New("endpoint must not be blank")
+	}
+	if strings.Contains(endpoint, "#") {
+		return "", errors.New("endpoint must not contain a fragment")
+	}
+
+	parsed, err := url.Parse(endpoint)
+	if err != nil {
+		return "", errors.New("endpoint must be a valid URL")
+	}
+	parsed.Scheme = strings.ToLower(parsed.Scheme)
+	if parsed.Scheme != "http" && parsed.Scheme != "https" {
+		return "", errors.New("endpoint must use http or https")
+	}
+	if !parsed.IsAbs() || parsed.Hostname() == "" {
+		return "", errors.New("endpoint must be absolute and include a host")
+	}
+	if parsed.User != nil {
+		return "", errors.New("endpoint must not contain user information")
+	}
+	if parsed.RawQuery != "" || parsed.ForceQuery {
+		return "", errors.New("endpoint must not contain a query string")
+	}
+
+	return parsed.String(), nil
+}

internal/domain/endpoint_test.go

@@ -0,0 +1,47 @@
+package domain
+
+import "testing"
+
+func TestNormalizeOpenAICompatibleBaseEndpoint(t *testing.T) {
+	tests := []struct {
+		name     string
+		endpoint string
+		want     string
+		wantErr  bool
+	}{
+		{name: "http host", endpoint: "http://provider.example", want: "http://provider.example"},
+		{name: "https nested path and whitespace", endpoint: "  HTTPS://provider.example/api/openai/v1  ", want: "https://provider.example/api/openai/v1"},
+		{name: "IPv4 host and port", endpoint: "http://127.0.0.1:8080/v1", want: "http://127.0.0.1:8080/v1"},
+		{name: "IPv6 host and port", endpoint: "https://[::1]:8443/v1", want: "https://[::1]:8443/v1"},
+		{name: "repeated trailing slashes", endpoint: "https://provider.example/v1///", want: "https://provider.example/v1///"},
+		{name: "blank", endpoint: " \t\n ", wantErr: true},
+		{name: "relative path", endpoint: "/api/v1", wantErr: true},
+		{name: "scheme relative", endpoint: "//provider.example/v1", wantErr: true},
+		{name: "missing host", endpoint: "https:///v1", wantErr: true},
+		{name: "unsupported scheme", endpoint: "ftp://provider.example/v1", wantErr: true},
+		{name: "user information", endpoint: "https://user:secret@provider.example/v1", wantErr: true},
+		{name: "query", endpoint: "https://provider.example/v1?mode=chat", wantErr: true},
+		{name: "empty query", endpoint: "https://provider.example/v1?", wantErr: true},
+		{name: "fragment", endpoint: "https://provider.example/v1#chat", wantErr: true},
+		{name: "empty fragment", endpoint: "https://provider.example/v1#", wantErr: true},
+		{name: "malformed URL", endpoint: "https://provider.example/%zz", wantErr: true},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			got, err := NormalizeOpenAICompatibleBaseEndpoint(tc.endpoint)
+			if tc.wantErr {
+				if err == nil {
+					t.Fatalf("expected endpoint error, got %q", got)
+				}
+				return
+			}
+			if err != nil {
+				t.Fatalf("normalize endpoint: %v", err)
+			}
+			if got != tc.want {
+				t.Fatalf("normalized endpoint = %q, want %q", got, tc.want)
+			}
+		})
+	}
+}

internal/llm/openai_compatible_client.go

@@ -51,9 +51,11 @@ type OpenAICompatibleClient struct {
 }
 
 func NewOpenAICompatibleClient(cfg OpenAICompatibleConfig) (*OpenAICompatibleClient, error) {
-	baseURL := strings.TrimSpace(cfg.BaseURL)
-	if baseURL != "" {
-		if _, err := url.ParseRequestURI(baseURL); err != nil {
+	baseURL := ""
+	if strings.TrimSpace(cfg.BaseURL) != "" {
+		var err error
+		baseURL, err = domain.NormalizeOpenAICompatibleBaseEndpoint(cfg.BaseURL)
+		if err != nil {
 			return nil, fmt.Errorf("%w: invalid base URL: %v", ErrInvalidConfig, err)
 		}
 	}
@@ -75,7 +77,7 @@ func NewOpenAICompatibleClient(cfg OpenAICompatibleConfig) (*OpenAICompatibleCli
 	}
 
 	return &OpenAICompatibleClient{
-		baseURL:      strings.TrimRight(baseURL, "/"),
+		baseURL:      baseURL,
 		defaultModel: cfg.Model,
 		httpClient:   client,
 	}, nil
@@ -86,14 +88,18 @@ func (c *OpenAICompatibleClient) Generate(ctx context.Context, req domain.Genera
 		return nil, fmt.Errorf("%w: %v", ErrInvalidRequest, err)
 	}
 
-	endpoint := strings.TrimSpace(req.Target.Endpoint)
-	if endpoint == "" {
-		endpoint = c.baseURL
+	selectedEndpoint := req.Target.Endpoint
+	if strings.TrimSpace(selectedEndpoint) == "" {
+		selectedEndpoint = c.baseURL
 	}
-	if endpoint == "" {
-		return nil, fmt.Errorf("%w: endpoint is required", ErrInvalidRequest)
+	endpoint, err := domain.NormalizeOpenAICompatibleBaseEndpoint(selectedEndpoint)
+	if err != nil {
+		return nil, fmt.Errorf("%w: invalid endpoint: %v", ErrInvalidRequest, err)
+	}
+	endpoint, err = url.JoinPath(endpoint, defaults.OpenAIChatCompletionsPath)
+	if err != nil {
+		return nil, fmt.Errorf("%w: invalid endpoint path: %v", ErrInvalidRequest, err)
 	}
-	endpoint = strings.TrimRight(endpoint, "/") + defaults.OpenAIChatCompletionsPath
 
 	wireReq, err := openAIChatRequestFromGenerateRequest(req, c.defaultModel)
 	if err != nil {

internal/llm/openai_compatible_client_test.go

@@ -64,14 +64,21 @@ func assertDeadlineNear(t *testing.T, deadline, before, after time.Time, duratio
 }
 
 func TestNewOpenAICompatibleClientRejectsInvalidBaseURL(t *testing.T) {
-	_, err := NewOpenAICompatibleClient(OpenAICompatibleConfig{
-		BaseURL: "://invalid",
-	})
-	if err == nil {
-		t.Fatal("expected invalid configuration error")
-	}
-	if !errors.Is(err, ErrInvalidConfig) {
-		t.Fatalf("expected ErrInvalidConfig, got %v", err)
+	for _, endpoint := range []string{
+		"://invalid",
+		"/v1",
+		"https:///v1",
+		"ftp://provider.example/v1",
+		"https://user@provider.example/v1",
+		"https://provider.example/v1?mode=chat",
+		"https://provider.example/v1#chat",
+	} {
+		t.Run(endpoint, func(t *testing.T) {
+			_, err := NewOpenAICompatibleClient(OpenAICompatibleConfig{BaseURL: endpoint})
+			if !errors.Is(err, ErrInvalidConfig) {
+				t.Fatalf("expected ErrInvalidConfig, got %v", err)
+			}
+		})
 	}
 }
 
@@ -1312,6 +1319,94 @@ func TestOpenAICompatibleClientAllowsEmptyConfiguredBaseURL(t *testing.T) {
 	}
 }
 
+func TestOpenAICompatibleClientComposesCompletionURL(t *testing.T) {
+	tests := []struct {
+		name    string
+		baseURL string
+		wantURL string
+	}{
+		{name: "HTTP host", baseURL: "http://provider.example", wantURL: "http://provider.example/chat/completions"},
+		{name: "HTTPS host", baseURL: "https://provider.example", wantURL: "https://provider.example/chat/completions"},
+		{name: "nested path", baseURL: "https://provider.example/api/openai/v1", wantURL: "https://provider.example/api/openai/v1/chat/completions"},
+		{name: "trailing slash", baseURL: "https://provider.example/v1/", wantURL: "https://provider.example/v1/chat/completions"},
+		{name: "repeated trailing slashes", baseURL: "  https://provider.example/api/v1///  ", wantURL: "https://provider.example/api/v1/chat/completions"},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			var selectedURL string
+			client, err := NewOpenAICompatibleClient(OpenAICompatibleConfig{
+				BaseURL: tc.baseURL,
+				Model:   "m",
+				HTTPClient: &http.Client{Transport: roundTripFunc(func(req *http.Request) (*http.Response, error) {
+					selectedURL = req.URL.String()
+					return &http.Response{
+						StatusCode: http.StatusOK,
+						Header:     make(http.Header),
+						Body:       io.NopCloser(strings.NewReader(`{"choices":[{"message":{"content":"ok"}}]}`)),
+						Request:    req,
+					}, nil
+				})},
+			})
+			if err != nil {
+				t.Fatalf("construct client: %v", err)
+			}
+
+			_, err = client.Generate(context.Background(), domain.GenerateRequest{
+				Prompt: domain.RenderedPrompt{Messages: []domain.RenderedMessage{{Role: "user", Content: "hi"}}},
+			})
+			if err != nil {
+				t.Fatalf("generate: %v", err)
+			}
+			if selectedURL != tc.wantURL {
+				t.Fatalf("selected URL = %q, want %q", selectedURL, tc.wantURL)
+			}
+		})
+	}
+}
+
+func TestOpenAICompatibleClientRejectsInvalidSelectedEndpointBeforeTransport(t *testing.T) {
+	invalidEndpoints := []string{
+		"/v1",
+		"https:///v1",
+		"ftp://provider.example/v1",
+		"https://user@provider.example/v1",
+		"https://provider.example/v1?mode=chat",
+		"https://provider.example/v1#chat",
+		"https://sensitive-endpoint.example/%zz",
+	}
+	for _, endpoint := range invalidEndpoints {
+		t.Run(endpoint, func(t *testing.T) {
+			transportCalls := 0
+			client, err := NewOpenAICompatibleClient(OpenAICompatibleConfig{
+				BaseURL: "https://configured.example/v1",
+				Model:   "m",
+				HTTPClient: &http.Client{Transport: roundTripFunc(func(*http.Request) (*http.Response, error) {
+					transportCalls++
+					return nil, errors.New("transport must not be called")
+				})},
+			})
+			if err != nil {
+				t.Fatalf("construct client: %v", err)
+			}
+
+			_, err = client.Generate(context.Background(), domain.GenerateRequest{
+				Prompt: domain.RenderedPrompt{Messages: []domain.RenderedMessage{{Role: "user", Content: "hi"}}},
+				Target: domain.ExecutionTarget{Endpoint: endpoint},
+			})
+			if !errors.Is(err, ErrInvalidRequest) {
+				t.Fatalf("expected ErrInvalidRequest, got %v", err)
+			}
+			if strings.Contains(err.Error(), endpoint) {
+				t.Fatalf("error exposed selected endpoint %q: %v", endpoint, err)
+			}
+			if transportCalls != 0 {
+				t.Fatalf("transport calls = %d, want 0", transportCalls)
+			}
+		})
+	}
+}
+
 func TestOpenAICompatibleClientRequiresEndpointWhenUnsetEverywhere(t *testing.T) {
 	client, err := NewOpenAICompatibleClient(OpenAICompatibleConfig{
 		BaseURL: "",

internal/profile/filesystem_repository.go

@@ -132,7 +132,7 @@ func loadProfile(ctx context.Context, fsys fs.FS, root string, id string) (*doma
 		if err != nil {
 			return nil, fmt.Errorf("%w: %s: %v", ErrInvalidProfile, relPath, err)
 		}
-		if err := validateProfile(prof); err != nil {
+		if err := normalizeAndValidateProfile(prof); err != nil {
 			if errors.Is(err, ErrRawAPIKeyNotAllowed) {
 				return nil, fmt.Errorf("%w: %s", err, relPath)
 			}
@@ -256,13 +256,21 @@ func requireYAMLStreamEnd(decoder *yaml.Decoder) error {
 	return errors.New("profile file must contain exactly one YAML document")
 }
 
-func validateProfile(p *domain.ExecutionProfile) error {
+func normalizeAndValidateProfile(p *domain.ExecutionProfile) error {
 	if strings.TrimSpace(p.ID) == "" {
 		return errors.New("id is required")
 	}
-	if strings.TrimSpace(p.BackendID) == "" && strings.TrimSpace(p.Endpoint) == "" {
+	p.Endpoint = strings.TrimSpace(p.Endpoint)
+	if strings.TrimSpace(p.BackendID) == "" && p.Endpoint == "" {
 		return errors.New("backend or endpoint is required")
 	}
+	if p.Endpoint != "" {
+		endpoint, err := domain.NormalizeOpenAICompatibleBaseEndpoint(p.Endpoint)
+		if err != nil {
+			return err
+		}
+		p.Endpoint = endpoint
+	}
 	if strings.TrimSpace(p.Model) == "" {
 		return errors.New("model is required")
 	}

internal/profile/repository_test.go

@@ -63,7 +63,7 @@ func TestFilesystemRepository_GetProfile(t *testing.T) {
 			wantErr      bool
 		}{
 			{name: "backend only", connection: "backend: '  openrouter  '", wantBackend: "openrouter"},
-			{name: "endpoint only", connection: "endpoint: http://localhost:8000/v1", wantEndpoint: "http://localhost:8000/v1"},
+			{name: "endpoint only", connection: "endpoint: '  https://localhost:8000/nested/v1  '", wantEndpoint: "https://localhost:8000/nested/v1"},
 			{name: "both", connection: "backend: openrouter\nendpoint: http://localhost:8000/v1", wantBackend: "openrouter", wantEndpoint: "http://localhost:8000/v1"},
 			{name: "neither", wantErr: true},
 			{name: "blank backend", connection: "backend: '   '", wantErr: true},
@@ -351,6 +351,43 @@ model: second
 	})
 }
 
+func TestProfileRepositoriesRejectInvalidEndpoints(t *testing.T) {
+	tests := []struct {
+		name        string
+		endpoint    string
+		withBackend bool
+	}{
+		{name: "relative", endpoint: "/v1"},
+		{name: "missing host", endpoint: "https:///v1"},
+		{name: "unsupported scheme", endpoint: "ftp://provider.example/v1"},
+		{name: "user information", endpoint: "https://user@provider.example/v1"},
+		{name: "query", endpoint: "https://provider.example/v1?mode=chat"},
+		{name: "fragment", endpoint: "https://provider.example/v1#chat"},
+		{name: "backend with invalid override", endpoint: "/v1", withBackend: true},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			backend := ""
+			if tc.withBackend {
+				backend = "backend: openrouter\n"
+			}
+			repo := NewFSRepository(fstest.MapFS{
+				"profiles/invalid.yaml": profileMapFile(fmt.Sprintf(
+					"id: invalid-endpoint\nmodel: model\n%sendpoint: %q\n",
+					backend,
+					tc.endpoint,
+				)),
+			}, "profiles")
+
+			_, err := repo.GetProfile(context.Background(), "invalid-endpoint")
+			if !errors.Is(err, ErrInvalidProfile) {
+				t.Fatalf("expected ErrInvalidProfile, got %v", err)
+			}
+		})
+	}
+}
+
 func TestProfileRepositoriesValidateExtraParams(t *testing.T) {
 	const validProfile = `
 id: selected-profile

internal/usecase/execution_settings_test.go

@@ -31,3 +31,53 @@ func TestRunnerPrepareExecutionRejectsInvalidExecutionSettings(t *testing.T) {
 		t.Fatalf("expected ErrInvalidRequest, got %v", err)
 	}
 }
+
+func TestRunnerPrepareExecutionValidatesAndNormalizesRequestEndpoints(t *testing.T) {
+	newRunner := func() *Runner {
+		return NewRunner(
+			&fakePromptRepo{def: promptDef(domain.FormatText, domain.ValidationNone, 0)},
+			&fakeExecutionProfileRepo{profiles: map[string]*domain.ExecutionProfile{"exec": defaultExecutionProfile()}},
+			nil,
+			defaultArtifactReader(),
+			defaultRenderer(),
+			&fakeLLM{forbid: true},
+			nil,
+			nil,
+		)
+	}
+
+	invalidEndpoints := []string{
+		"/v1",
+		"https:///v1",
+		"ftp://provider.example/v1",
+		"https://user@provider.example/v1",
+		"https://provider.example/v1?mode=chat",
+		"https://provider.example/v1#chat",
+	}
+	for _, endpoint := range invalidEndpoints {
+		t.Run(endpoint, func(t *testing.T) {
+			_, err := newRunner().PrepareExecution(context.Background(), domain.RunRequest{
+				PromptID:  "p",
+				ProfileID: "exec",
+				Inputs:    singleInputRef(),
+				Execution: &domain.ExecutionTargetOverride{Endpoint: endpoint},
+			})
+			if !errors.Is(err, ErrInvalidRequest) {
+				t.Fatalf("expected ErrInvalidRequest, got %v", err)
+			}
+		})
+	}
+
+	prepared, err := newRunner().PrepareExecution(context.Background(), domain.RunRequest{
+		PromptID:  "p",
+		ProfileID: "exec",
+		Inputs:    singleInputRef(),
+		Execution: &domain.ExecutionTargetOverride{Endpoint: "  https://provider.example/nested/v1  "},
+	})
+	if err != nil {
+		t.Fatalf("prepare normalized endpoint: %v", err)
+	}
+	if got := prepared.Details().EffectiveModelParams.Endpoint; got != "https://provider.example/nested/v1" {
+		t.Fatalf("effective endpoint = %q", got)
+	}
+}

internal/usecase/profile_inspection.go

@@ -57,14 +57,19 @@ func (r *Runner) resolveProfileSelection(
 	}, nil
 }
 
-func validateResolvedExecutionTarget(target domain.ExecutionTarget) error {
-	if strings.TrimSpace(target.Endpoint) == "" {
-		return errors.New("execution endpoint is required")
+func normalizeResolvedExecutionTarget(target domain.ExecutionTarget) (domain.ExecutionTarget, error) {
+	endpoint, err := domain.NormalizeOpenAICompatibleBaseEndpoint(target.Endpoint)
+	if err != nil {
+		return domain.ExecutionTarget{}, fmt.Errorf("execution endpoint: %w", err)
 	}
+	target.Endpoint = endpoint
 	if strings.TrimSpace(target.Model) == "" {
-		return errors.New("execution model is required")
+		return domain.ExecutionTarget{}, errors.New("execution model is required")
 	}
-	return domain.ValidateExecutionTargetSettings(target)
+	if err := domain.ValidateExecutionTargetSettings(target); err != nil {
+		return domain.ExecutionTarget{}, err
+	}
+	return target, nil
 }
 
 // InspectProfile resolves one explicit profile without prompt or execution work.
@@ -87,7 +92,8 @@ func (r *Runner) InspectProfile(
 		return nil, err
 	}
 	target, _ := resolveExecutionTarget(selection.backend, selection.profile, nil)
-	if err := validateResolvedExecutionTarget(target); err != nil {
+	target, err = normalizeResolvedExecutionTarget(target)
+	if err != nil {
 		return nil, fmt.Errorf("%w: %w", ErrProfileLoad, err)
 	}
 	target.APIKey = ""

internal/usecase/runner.go

@@ -317,7 +317,8 @@ func (r *Runner) resolvePreparation(
 
 	effectiveModel, targetPresence := resolveExecutionTarget(selection.backend, selection.profile, req.Execution)
 	effectiveModel.APIKey = req.APIKey
-	if err := validateResolvedExecutionTarget(effectiveModel); err != nil {
+	effectiveModel, err = normalizeResolvedExecutionTarget(effectiveModel)
+	if err != nil {
 		return nil, fmt.Errorf("%w: %w", ErrInvalidRequest, err)
 	}
 	if err := validateAPIKey(effectiveModel.APIKeyEnv, effectiveModel.APIKey, effectiveModel.APIKeyRequired); err != nil {