fix: address security and code quality issues in OpenAI channel

- Make CORS policy configurable with AllowOrigins config
- Default to localhost only for security
- Refactor resolveFromModelCandidates to reduce complexity
- Improve error handling consistency with proper logging
- Fix translateConversation boundary case handling
- Add comprehensive tests for CORS and message validation

Fixes review comments from @yinwm and @alexhoshina

pkg/agent/instance.go

@@ -154,47 +154,9 @@ func NewAgentInstance(
 		Primary:   model,
 		Fallbacks: fallbacks,
 	}
-	resolveFromModelList := func(raw string) (string, bool) {
-		ensureProtocol := func(model string) string {
-			model = strings.TrimSpace(model)
-			if model == "" {
-				return ""
-			}
-			if strings.Contains(model, "/") {
-				return model
-			}
-			return "openai/" + model
-		}
-
-		raw = strings.TrimSpace(raw)
-		if raw == "" {
-			return "", false
-		}
-
-		if cfg != nil {
-			if mc, err := cfg.GetModelConfig(raw); err == nil && mc != nil && strings.TrimSpace(mc.Model) != "" {
-				return ensureProtocol(mc.Model), true
-			}
-
-			for i := range cfg.ModelList {
-				fullModel := strings.TrimSpace(cfg.ModelList[i].Model)
-				if fullModel == "" {
-					continue
-				}
-				if fullModel == raw {
-					return ensureProtocol(fullModel), true
-				}
-				_, modelID := providers.ExtractProtocol(fullModel)
-				if modelID == raw {
-					return ensureProtocol(fullModel), true
-				}
-			}
-		}
-
-		return "", false
-	}
-
-	candidates := providers.ResolveCandidatesWithLookup(modelCfg, defaults.Provider, resolveFromModelList)
+	candidates := providers.ResolveCandidatesWithLookup(modelCfg, defaults.Provider, func(raw string) (string, bool) {
+		return resolveFromModelList(cfg, raw)
+	})
 
 	// Model routing setup: pre-resolve light model candidates at creation time
 	// to avoid repeated model_list lookups on every incoming message.
@@ -202,7 +164,9 @@ func NewAgentInstance(
 	var lightCandidates []providers.FallbackCandidate
 	if rc := defaults.Routing; rc != nil && rc.Enabled && rc.LightModel != "" {
 		lightModelCfg := providers.ModelConfig{Primary: rc.LightModel}
-		resolved := providers.ResolveCandidatesWithLookup(lightModelCfg, defaults.Provider, resolveFromModelList)
+		resolved := providers.ResolveCandidatesWithLookup(lightModelCfg, defaults.Provider, func(raw string) (string, bool) {
+			return resolveFromModelList(cfg, raw)
+		})
 		if len(resolved) > 0 {
 			router = routing.New(routing.RouterConfig{
 				LightModel: rc.LightModel,

pkg/agent/loop.go

@@ -1514,47 +1514,13 @@ func (al *AgentLoop) resolveRequestedModelCandidates(
 	}
 
 	cfg := al.GetConfig()
-	resolveFromModelList := func(raw string) (string, bool) {
-		ensureProtocol := func(model string) string {
-			if model == "" {
-				return ""
-			}
-			if strings.Contains(model, "/") {
-				return model
-			}
-			return "openai/" + model
-		}
-
-		raw = strings.TrimSpace(raw)
-		if raw == "" || cfg == nil {
-			return "", false
-		}
-
-		if mc, err := cfg.GetModelConfig(raw); err == nil && mc != nil && strings.TrimSpace(mc.Model) != "" {
-			return ensureProtocol(mc.Model), true
-		}
-
-		for i := range cfg.ModelList {
-			fullModel := strings.TrimSpace(cfg.ModelList[i].Model)
-			if fullModel == "" {
-				continue
-			}
-			if fullModel == raw {
-				return ensureProtocol(fullModel), true
-			}
-			_, modelID := providers.ExtractProtocol(fullModel)
-			if modelID == raw {
-				return ensureProtocol(fullModel), true
-			}
-		}
-
-		return "", false
-	}
 
 	candidates := providers.ResolveCandidatesWithLookup(
 		providers.ModelConfig{Primary: requestedModel},
 		al.cfg.Agents.Defaults.Provider,
-		resolveFromModelList,
+		func(raw string) (string, bool) {
+			return resolveFromModelList(cfg, raw)
+		},
 	)
 	if len(candidates) == 0 {
 		return nil, "", fmt.Errorf("requested model %q not found in model_list", requestedModel)

pkg/agent/model_resolution.go

@@ -0,0 +1,46 @@
+package agent
+
+import (
+	"strings"
+
+	"github.com/sipeed/picoclaw/pkg/config"
+	"github.com/sipeed/picoclaw/pkg/providers"
+)
+
+func ensureProtocol(model string) string {
+	model = strings.TrimSpace(model)
+	if model == "" {
+		return ""
+	}
+	if strings.Contains(model, "/") {
+		return model
+	}
+	return "openai/" + model
+}
+
+func resolveFromModelList(cfg *config.Config, raw string) (string, bool) {
+	raw = strings.TrimSpace(raw)
+	if raw == "" || cfg == nil {
+		return "", false
+	}
+
+	if mc, err := cfg.GetModelConfig(raw); err == nil && mc != nil && strings.TrimSpace(mc.Model) != "" {
+		return ensureProtocol(mc.Model), true
+	}
+
+	for i := range cfg.ModelList {
+		fullModel := strings.TrimSpace(cfg.ModelList[i].Model)
+		if fullModel == "" {
+			continue
+		}
+		if fullModel == raw {
+			return ensureProtocol(fullModel), true
+		}
+		_, modelID := providers.ExtractProtocol(fullModel)
+		if modelID == raw {
+			return ensureProtocol(fullModel), true
+		}
+	}
+
+	return "", false
+}

pkg/channels/openai_api/openai_api.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"net"
 	"net/http"
+	"net/url"
 	"sort"
 	"strconv"
 	"strings"
@@ -28,6 +29,8 @@ const (
 	responseWaitTimeout = 5 * time.Minute
 )
 
+var defaultAllowedOrigins = []string{"localhost"}
+
 type responseTask struct {
 	ctx     context.Context
 	cancel  context.CancelFunc
@@ -68,6 +71,7 @@ type translatedConversation struct {
 type OpenAIAPIChannel struct {
 	*channels.BaseChannel
 	config         config.OpenAIAPIConfig
+	allowedOrigins []string
 	listenHost     string
 	models         []config.ModelConfig
 	messageBus     *bus.MessageBus
@@ -87,16 +91,20 @@ func NewOpenAIAPIChannel(cfg *config.Config, messageBus *bus.MessageBus) (*OpenA
 		return nil, fmt.Errorf("openai_api api_key is required")
 	}
 
+	channelConfig := cfg.Channels.OpenAIAPI
+	channelConfig.AllowOrigins = normalizeAllowedOrigins(channelConfig.AllowOrigins)
+
 	listenHost := strings.TrimSpace(cfg.Gateway.Host)
 	if listenHost == "" {
 		listenHost = "127.0.0.1"
 	}
 
-	base := channels.NewBaseChannel("openai_api", cfg.Channels.OpenAIAPI, messageBus, nil)
+	base := channels.NewBaseChannel("openai_api", channelConfig, messageBus, nil)
 
 	return &OpenAIAPIChannel{
 		BaseChannel:    base,
-		config:      cfg.Channels.OpenAIAPI,
+		config:         channelConfig,
+		allowedOrigins: append([]string(nil), channelConfig.AllowOrigins...),
 		listenHost:     listenHost,
 		models:         append([]config.ModelConfig(nil), cfg.ModelList...),
 		messageBus:     messageBus,
@@ -197,19 +205,30 @@ func (c *OpenAIAPIChannel) Send(ctx context.Context, msg bus.OutboundMessage) er
 }
 
 func (c *OpenAIAPIChannel) handleOptions(w http.ResponseWriter, r *http.Request) {
-	setCORSHeaders(w)
+	if !c.applyCORSHeaders(w, r) {
+		return
+	}
 	w.WriteHeader(http.StatusNoContent)
 }
 
 func (c *OpenAIAPIChannel) handleHealth(w http.ResponseWriter, r *http.Request) {
+	if !c.applyCORSHeaders(w, r) {
+		return
+	}
 	w.Header().Set("Content-Type", "application/json")
-	json.NewEncoder(w).Encode(map[string]any{"status": "ok"})
+	if err := writeJSONResponse(w, http.StatusOK, map[string]any{"status": "ok"}); err != nil {
+		return
+	}
 }
 
 func (c *OpenAIAPIChannel) handleModels(w http.ResponseWriter, r *http.Request) {
-	setCORSHeaders(w)
+	if !c.applyCORSHeaders(w, r) {
+		return
+	}
 	if !c.authenticate(r) {
-		writeOpenAIError(w, http.StatusUnauthorized, "Invalid API key", "invalid_request_error", "invalid_api_key")
+		if err := writeOpenAIError(w, http.StatusUnauthorized, "Invalid API key", "invalid_request_error", "invalid_api_key"); err != nil {
+			return
+		}
 		return
 	}
 
@@ -241,42 +260,64 @@ func (c *OpenAIAPIChannel) handleModels(w http.ResponseWriter, r *http.Request)
 	})
 
 	w.Header().Set("Content-Type", "application/json")
-	json.NewEncoder(w).Encode(map[string]any{
+	if err := writeJSONResponse(w, http.StatusOK, map[string]any{
 		"object": "list",
 		"data":   items,
-	})
+	}); err != nil {
+		return
+	}
 }
 
 func (c *OpenAIAPIChannel) handleChatCompletions(w http.ResponseWriter, r *http.Request) {
-	setCORSHeaders(w)
+	if !c.applyCORSHeaders(w, r) {
+		return
+	}
 	if !c.authenticate(r) {
-		writeOpenAIError(w, http.StatusUnauthorized, "Invalid API key", "invalid_request_error", "invalid_api_key")
+		if err := writeOpenAIError(w, http.StatusUnauthorized, "Invalid API key", "invalid_request_error", "invalid_api_key"); err != nil {
+			return
+		}
 		return
 	}
 
 	var req chatCompletionRequest
 	decoder := json.NewDecoder(http.MaxBytesReader(w, r.Body, maxRequestBodySize))
 	if err := decoder.Decode(&req); err != nil {
-		writeOpenAIError(w, http.StatusBadRequest, "Invalid JSON request body", "invalid_request_error", "invalid_json")
+		logger.WarnCF("openai_api", "Invalid chat completion request body", map[string]any{
+			"error": err.Error(),
+		})
+		if err := writeOpenAIError(w, http.StatusBadRequest, "Invalid JSON request body", "invalid_request_error", "invalid_json"); err != nil {
+			return
+		}
 		return
 	}
 
 	if strings.TrimSpace(req.Model) == "" {
-		writeOpenAIError(w, http.StatusBadRequest, "model is required", "invalid_request_error", "missing_model")
+		if err := writeOpenAIError(w, http.StatusBadRequest, "model is required", "invalid_request_error", "missing_model"); err != nil {
+			return
+		}
 		return
 	}
 	if !c.supportsModel(req.Model) {
-		writeOpenAIError(w, http.StatusBadRequest, fmt.Sprintf("model %q is not configured", req.Model), "invalid_request_error", "model_not_found")
+		if err := writeOpenAIError(w, http.StatusBadRequest, fmt.Sprintf("model %q is not configured", req.Model), "invalid_request_error", "model_not_found"); err != nil {
+			return
+		}
 		return
 	}
 	if len(req.Messages) == 0 {
-		writeOpenAIError(w, http.StatusBadRequest, "messages must not be empty", "invalid_request_error", "missing_messages")
+		if err := writeOpenAIError(w, http.StatusBadRequest, "messages must not be empty", "invalid_request_error", "missing_messages"); err != nil {
+			return
+		}
 		return
 	}
 
 	translated, err := translateConversation(req.Messages)
 	if err != nil {
-		writeOpenAIError(w, http.StatusBadRequest, err.Error(), "invalid_request_error", "invalid_messages")
+		logger.WarnCF("openai_api", "Invalid chat completion message sequence", map[string]any{
+			"error": err.Error(),
+		})
+		if err := writeOpenAIError(w, http.StatusBadRequest, err.Error(), "invalid_request_error", "invalid_messages"); err != nil {
+			return
+		}
 		return
 	}
 
@@ -302,7 +343,12 @@ func (c *OpenAIAPIChannel) handleChatCompletions(w http.ResponseWriter, r *http.
 	if len(translated.InjectedHistory) > 0 {
 		rawHistory, err := json.Marshal(translated.InjectedHistory)
 		if err != nil {
-			writeOpenAIError(w, http.StatusInternalServerError, "Failed to encode conversation history", "server_error", "history_encode_failed")
+			logger.ErrorCF("openai_api", "Failed to encode injected history", map[string]any{
+				"error": err.Error(),
+			})
+			if err := writeOpenAIError(w, http.StatusInternalServerError, "Failed to encode conversation history", "server_error", "history_encode_failed"); err != nil {
+				return
+			}
 			return
 		}
 		metadata["injected_history"] = string(rawHistory)
@@ -327,13 +373,23 @@ func (c *OpenAIAPIChannel) handleChatCompletions(w http.ResponseWriter, r *http.
 		Peer:     bus.Peer{Kind: "direct", ID: senderID},
 		Metadata: metadata,
 	}); err != nil {
-		writeOpenAIError(w, http.StatusBadGateway, fmt.Sprintf("Failed to submit request: %v", err), "server_error", "publish_failed")
+		logger.ErrorCF("openai_api", "Failed to publish inbound OpenAI API request", map[string]any{
+			"error": err.Error(),
+		})
+		if err := writeOpenAIError(w, http.StatusBadGateway, fmt.Sprintf("Failed to submit request: %v", err), "server_error", "publish_failed"); err != nil {
+			return
+		}
 		return
 	}
 
 	firstChunk, err := waitForFirstChunk(reqCtx, task)
 	if err != nil {
-		writeOpenAIError(w, http.StatusGatewayTimeout, "Timed out waiting for assistant response", "server_error", "response_timeout")
+		logger.ErrorCF("openai_api", "Timed out waiting for first assistant chunk", map[string]any{
+			"error": err.Error(),
+		})
+		if err := writeOpenAIError(w, http.StatusGatewayTimeout, "Timed out waiting for assistant response", "server_error", "response_timeout"); err != nil {
+			return
+		}
 		return
 	}
 
@@ -343,7 +399,9 @@ func (c *OpenAIAPIChannel) handleChatCompletions(w http.ResponseWriter, r *http.
 	if req.Stream {
 		flusher, ok := w.(http.Flusher)
 		if !ok {
-			writeOpenAIError(w, http.StatusInternalServerError, "Streaming is not supported by this server", "server_error", "stream_not_supported")
+			if err := writeOpenAIError(w, http.StatusInternalServerError, "Streaming is not supported by this server", "server_error", "stream_not_supported"); err != nil {
+				return
+			}
 			return
 		}
 
@@ -352,28 +410,49 @@ func (c *OpenAIAPIChannel) handleChatCompletions(w http.ResponseWriter, r *http.
 		w.Header().Set("Connection", "keep-alive")
 
 		if err := writeChatCompletionChunk(w, completionID, createdAt, req.Model, firstChunk, true, false); err != nil {
+			logger.ErrorCF("openai_api", "Failed to write first streaming chunk", map[string]any{
+				"error": err.Error(),
+			})
 			return
 		}
 		flusher.Flush()
 
 		if err := streamRemainingChunks(reqCtx, task, w, flusher, completionID, createdAt, req.Model); err != nil {
+			logger.ErrorCF("openai_api", "Failed to stream assistant chunks", map[string]any{
+				"error": err.Error(),
+			})
 			return
 		}
 
-		_ = writeChatCompletionChunk(w, completionID, createdAt, req.Model, "", false, true)
-		_, _ = fmt.Fprint(w, "data: [DONE]\n\n")
+		if err := writeChatCompletionChunk(w, completionID, createdAt, req.Model, "", false, true); err != nil {
+			logger.ErrorCF("openai_api", "Failed to write final streaming chunk", map[string]any{
+				"error": err.Error(),
+			})
+			return
+		}
+		if _, err := fmt.Fprint(w, "data: [DONE]\n\n"); err != nil {
+			logger.ErrorCF("openai_api", "Failed to write stream terminator", map[string]any{
+				"error": err.Error(),
+			})
+			return
+		}
 		flusher.Flush()
 		return
 	}
 
 	chunks, err := collectRemainingChunks(reqCtx, task, []string{firstChunk})
 	if err != nil {
-		writeOpenAIError(w, http.StatusGatewayTimeout, "Timed out waiting for assistant response", "server_error", "response_timeout")
+		logger.ErrorCF("openai_api", "Timed out collecting assistant response chunks", map[string]any{
+			"error": err.Error(),
+		})
+		if err := writeOpenAIError(w, http.StatusGatewayTimeout, "Timed out waiting for assistant response", "server_error", "response_timeout"); err != nil {
+			return
+		}
 		return
 	}
 
 	w.Header().Set("Content-Type", "application/json")
-	json.NewEncoder(w).Encode(map[string]any{
+	if err := writeJSONResponse(w, http.StatusOK, map[string]any{
 		"id":      completionID,
 		"object":  "chat.completion",
 		"created": createdAt,
@@ -388,7 +467,9 @@ func (c *OpenAIAPIChannel) handleChatCompletions(w http.ResponseWriter, r *http.
 				"finish_reason": "stop",
 			},
 		},
-	})
+	}); err != nil {
+		return
+	}
 }
 
 func translateConversation(messages []chatCompletionMessage) (translatedConversation, error) {
@@ -432,21 +513,17 @@ func translateConversation(messages []chatCompletionMessage) (translatedConversa
 	out.ExtraSystemPrompt = strings.Join(systemPrompts, "\n\n")
 	last := nonSystem[len(nonSystem)-1]
 
-	if last.Role == "user" && strings.TrimSpace(last.Content) != "" {
-		out.CurrentMessage = last.Content
-		out.InjectedHistory = append([]providers.Message(nil), nonSystem[:len(nonSystem)-1]...)
-		return out, nil
-	}
-
-	out.InjectedHistory = append([]providers.Message(nil), nonSystem...)
 	switch last.Role {
 	case "assistant":
-		out.CurrentMessage = "Continue the conversation with the next assistant response."
+		return translatedConversation{}, fmt.Errorf("last message must be a user message, got assistant")
 	case "tool":
-		out.CurrentMessage = "Continue the conversation after the tool result above."
-	default:
-		out.CurrentMessage = "Continue the conversation based on the previous messages."
+		return translatedConversation{}, fmt.Errorf("last message must be a user message, got tool")
 	}
+	if strings.TrimSpace(last.Content) == "" {
+		return translatedConversation{}, fmt.Errorf("last user message must not be empty")
+	}
+	out.CurrentMessage = last.Content
+	out.InjectedHistory = append([]providers.Message(nil), nonSystem[:len(nonSystem)-1]...)
 	return out, nil
 }
 
@@ -675,11 +752,9 @@ func writeChatCompletionChunk(
 	return err
 }
 
-func writeOpenAIError(w http.ResponseWriter, status int, message, errorType, code string) {
-	setCORSHeaders(w)
+func writeOpenAIError(w http.ResponseWriter, status int, message, errorType, code string) error {
 	w.Header().Set("Content-Type", "application/json")
-	w.WriteHeader(status)
-	_ = json.NewEncoder(w).Encode(map[string]any{
+	return writeJSONResponse(w, status, map[string]any{
 		"error": map[string]any{
 			"message": message,
 			"type":    errorType,
@@ -688,10 +763,94 @@ func writeOpenAIError(w http.ResponseWriter, status int, message, errorType, cod
 	})
 }
 
-func setCORSHeaders(w http.ResponseWriter) {
-	w.Header().Set("Access-Control-Allow-Origin", "*")
+func writeJSONResponse(w http.ResponseWriter, status int, payload any) error {
+	w.WriteHeader(status)
+	if err := json.NewEncoder(w).Encode(payload); err != nil {
+		logger.ErrorCF("openai_api", "Failed to write JSON response", map[string]any{
+			"error": err.Error(),
+		})
+		return err
+	}
+	return nil
+}
+
+func normalizeAllowedOrigins(origins []string) []string {
+	normalized := make([]string, 0, len(origins))
+	for _, origin := range origins {
+		origin = strings.TrimSpace(origin)
+		if origin == "" {
+			continue
+		}
+		normalized = append(normalized, origin)
+	}
+	if len(normalized) == 0 {
+		return append([]string(nil), defaultAllowedOrigins...)
+	}
+	return normalized
+}
+
+func (c *OpenAIAPIChannel) applyCORSHeaders(w http.ResponseWriter, r *http.Request) bool {
 	w.Header().Set("Access-Control-Allow-Headers", "Authorization, Content-Type")
 	w.Header().Set("Access-Control-Allow-Methods", "GET, POST, OPTIONS")
+	origin := strings.TrimSpace(r.Header.Get("Origin"))
+	if origin == "" {
+		return true
+	}
+	if !originAllowed(c.allowedOrigins, origin) {
+		logger.WarnCF("openai_api", "Rejected request from disallowed origin", map[string]any{
+			"origin": origin,
+		})
+		if err := writeOpenAIError(w, http.StatusForbidden, "Origin is not allowed", "invalid_request_error", "origin_not_allowed"); err != nil {
+			return false
+		}
+		return false
+	}
+	w.Header().Set("Access-Control-Allow-Origin", origin)
+	addVaryHeader(w.Header(), "Origin")
+	return true
+}
+
+func originAllowed(allowedOrigins []string, origin string) bool {
+	parsedOrigin, err := url.Parse(origin)
+	if err != nil || parsedOrigin.Scheme == "" || parsedOrigin.Host == "" {
+		return false
+	}
+
+	requestHost := strings.ToLower(parsedOrigin.Hostname())
+	for _, allowed := range allowedOrigins {
+		allowed = strings.TrimSpace(allowed)
+		if allowed == "" {
+			continue
+		}
+
+		if strings.Contains(allowed, "://") {
+			parsedAllowed, err := url.Parse(allowed)
+			if err != nil || parsedAllowed.Scheme == "" || parsedAllowed.Host == "" {
+				continue
+			}
+			if strings.EqualFold(parsedAllowed.Scheme, parsedOrigin.Scheme) && strings.EqualFold(parsedAllowed.Host, parsedOrigin.Host) {
+				return true
+			}
+			continue
+		}
+
+		if strings.EqualFold(allowed, requestHost) {
+			return true
+		}
+	}
+
+	return false
+}
+
+func addVaryHeader(headers http.Header, value string) {
+	for _, existing := range headers.Values("Vary") {
+		for _, part := range strings.Split(existing, ",") {
+			if strings.EqualFold(strings.TrimSpace(part), value) {
+				return
+			}
+		}
+	}
+	headers.Add("Vary", value)
 }
 
 func (c *OpenAIAPIChannel) authenticate(r *http.Request) bool {

pkg/channels/openai_api/openai_api_test.go

@@ -3,22 +3,33 @@ package openai_api
 import (
 	"context"
 	"encoding/json"
+	"errors"
 	"net/http"
 	"net/http/httptest"
+	"reflect"
 	"strings"
 	"testing"
 	"time"
 
 	"github.com/sipeed/picoclaw/pkg/bus"
 	"github.com/sipeed/picoclaw/pkg/config"
+	"github.com/sipeed/picoclaw/pkg/providers"
 )
 
 func newTestChannel(t *testing.T) (*OpenAIAPIChannel, *bus.MessageBus) {
 	t.Helper()
+	return newTestChannelWithConfig(t, nil)
+}
+
+func newTestChannelWithConfig(t *testing.T, mutate func(*config.Config)) (*OpenAIAPIChannel, *bus.MessageBus) {
+	t.Helper()
 
 	cfg := config.DefaultConfig()
 	cfg.Channels.OpenAIAPI.APIKey = "test-key"
 	cfg.Channels.OpenAIAPI.Port = 0
+	if mutate != nil {
+		mutate(cfg)
+	}
 
 	messageBus := bus.NewMessageBus()
 	channel, err := NewOpenAIAPIChannel(cfg, messageBus)
@@ -30,6 +41,23 @@ func newTestChannel(t *testing.T) (*OpenAIAPIChannel, *bus.MessageBus) {
 	return channel, messageBus
 }
 
+type failingResponseWriter struct {
+	headers http.Header
+}
+
+func (w *failingResponseWriter) Header() http.Header {
+	if w.headers == nil {
+		w.headers = make(http.Header)
+	}
+	return w.headers
+}
+
+func (w *failingResponseWriter) WriteHeader(statusCode int) {}
+
+func (w *failingResponseWriter) Write(p []byte) (int, error) {
+	return 0, errors.New("write failed")
+}
+
 func TestHandleChatCompletions_NonStreaming(t *testing.T) {
 	channel, messageBus := newTestChannel(t)
 
@@ -164,3 +192,196 @@ func TestHandleModels_RequiresAuth(t *testing.T) {
 		t.Fatalf("status = %d, want %d", rec.Code, http.StatusUnauthorized)
 	}
 }
+
+func TestHandleModels_AllowsConfiguredOrigin(t *testing.T) {
+	channel, _ := newTestChannelWithConfig(t, func(cfg *config.Config) {
+		cfg.Channels.OpenAIAPI.AllowOrigins = []string{"https://console.example.com"}
+	})
+
+	req := httptest.NewRequest(http.MethodGet, "/v1/models", nil)
+	req.Header.Set("Authorization", "Bearer test-key")
+	req.Header.Set("Origin", "https://console.example.com")
+	rec := httptest.NewRecorder()
+
+	channel.handleModels(rec, req)
+
+	if rec.Code != http.StatusOK {
+		t.Fatalf("status = %d, want %d, body=%s", rec.Code, http.StatusOK, rec.Body.String())
+	}
+	if got := rec.Header().Get("Access-Control-Allow-Origin"); got != "https://console.example.com" {
+		t.Fatalf("Access-Control-Allow-Origin = %q, want %q", got, "https://console.example.com")
+	}
+}
+
+func TestHandleModels_DefaultCORSAllowsLocalhost(t *testing.T) {
+	channel, _ := newTestChannelWithConfig(t, func(cfg *config.Config) {
+		cfg.Channels.OpenAIAPI.AllowOrigins = nil
+	})
+
+	req := httptest.NewRequest(http.MethodGet, "/v1/models", nil)
+	req.Header.Set("Authorization", "Bearer test-key")
+	req.Header.Set("Origin", "http://localhost:3000")
+	rec := httptest.NewRecorder()
+
+	channel.handleModels(rec, req)
+
+	if rec.Code != http.StatusOK {
+		t.Fatalf("status = %d, want %d, body=%s", rec.Code, http.StatusOK, rec.Body.String())
+	}
+	if got := rec.Header().Get("Access-Control-Allow-Origin"); got != "http://localhost:3000" {
+		t.Fatalf("Access-Control-Allow-Origin = %q, want %q", got, "http://localhost:3000")
+	}
+}
+
+func TestHandleModels_RejectsDisallowedOrigin(t *testing.T) {
+	channel, _ := newTestChannelWithConfig(t, func(cfg *config.Config) {
+		cfg.Channels.OpenAIAPI.AllowOrigins = []string{"https://console.example.com"}
+	})
+
+	req := httptest.NewRequest(http.MethodGet, "/v1/models", nil)
+	req.Header.Set("Authorization", "Bearer test-key")
+	req.Header.Set("Origin", "https://evil.example.com")
+	rec := httptest.NewRecorder()
+
+	channel.handleModels(rec, req)
+
+	if rec.Code != http.StatusForbidden {
+		t.Fatalf("status = %d, want %d, body=%s", rec.Code, http.StatusForbidden, rec.Body.String())
+	}
+	if got := rec.Header().Get("Access-Control-Allow-Origin"); got != "" {
+		t.Fatalf("Access-Control-Allow-Origin = %q, want empty", got)
+	}
+	if !strings.Contains(rec.Body.String(), "origin_not_allowed") {
+		t.Fatalf("response body missing origin_not_allowed: %s", rec.Body.String())
+	}
+}
+
+func TestHandleChatCompletions_RejectsInvalidLastMessage(t *testing.T) {
+	channel, _ := newTestChannel(t)
+
+	testCases := []struct {
+		name string
+		body string
+	}{
+		{
+			name: "assistant last",
+			body: `{
+				"model": "gpt-5.4",
+				"messages": [
+					{"role": "user", "content": "hello"},
+					{"role": "assistant", "content": "hi"}
+				]
+			}`,
+		},
+		{
+			name: "tool last",
+			body: `{
+				"model": "gpt-5.4",
+				"messages": [
+					{"role": "user", "content": "hello"},
+					{"role": "tool", "content": "tool result", "tool_call_id": "call_1"}
+				]
+			}`,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			req := httptest.NewRequest(http.MethodPost, "/v1/chat/completions", strings.NewReader(tc.body))
+			req.Header.Set("Authorization", "Bearer test-key")
+			rec := httptest.NewRecorder()
+
+			channel.handleChatCompletions(rec, req)
+
+			if rec.Code != http.StatusBadRequest {
+				t.Fatalf("status = %d, want %d, body=%s", rec.Code, http.StatusBadRequest, rec.Body.String())
+			}
+			if !strings.Contains(rec.Body.String(), "invalid_messages") {
+				t.Fatalf("response body missing invalid_messages: %s", rec.Body.String())
+			}
+		})
+	}
+}
+
+func TestTranslateConversation_RejectsInvalidLastMessage(t *testing.T) {
+	testCases := []struct {
+		name     string
+		messages []chatCompletionMessage
+		wantErr  string
+	}{
+		{
+			name: "assistant last",
+			messages: []chatCompletionMessage{
+				{Role: "user", Content: "hello"},
+				{Role: "assistant", Content: "hi"},
+			},
+			wantErr: "got assistant",
+		},
+		{
+			name: "tool last",
+			messages: []chatCompletionMessage{
+				{Role: "user", Content: "hello"},
+				{Role: "tool", Content: "tool result", ToolCallID: "call_1"},
+			},
+			wantErr: "got tool",
+		},
+		{
+			name: "empty user last",
+			messages: []chatCompletionMessage{
+				{Role: "user", Content: "hello"},
+				{Role: "user", Content: "   "},
+			},
+			wantErr: "must not be empty",
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			_, err := translateConversation(tc.messages)
+			if err == nil {
+				t.Fatal("translateConversation() error = nil, want non-nil")
+			}
+			if !strings.Contains(err.Error(), tc.wantErr) {
+				t.Fatalf("translateConversation() error = %q, want substring %q", err.Error(), tc.wantErr)
+			}
+		})
+	}
+}
+
+func TestTranslateConversation_ExtractsHistoryAndCurrentUserMessage(t *testing.T) {
+	translated, err := translateConversation([]chatCompletionMessage{
+		{Role: "system", Content: "be concise"},
+		{Role: "user", Content: "hello"},
+		{Role: "assistant", Content: "hi"},
+		{Role: "user", Content: "what next?"},
+	})
+	if err != nil {
+		t.Fatalf("translateConversation() error = %v", err)
+	}
+
+	if translated.CurrentMessage != "what next?" {
+		t.Fatalf("CurrentMessage = %q, want %q", translated.CurrentMessage, "what next?")
+	}
+	if translated.ExtraSystemPrompt != "be concise" {
+		t.Fatalf("ExtraSystemPrompt = %q, want %q", translated.ExtraSystemPrompt, "be concise")
+	}
+	wantHistory := []providers.Message{
+		{Role: "user", Content: "hello"},
+		{Role: "assistant", Content: "hi"},
+	}
+	if len(translated.InjectedHistory) != len(wantHistory) {
+		t.Fatalf("len(InjectedHistory) = %d, want %d", len(translated.InjectedHistory), len(wantHistory))
+	}
+	for i := range wantHistory {
+		if !reflect.DeepEqual(translated.InjectedHistory[i], wantHistory[i]) {
+			t.Fatalf("InjectedHistory[%d] = %+v, want %+v", i, translated.InjectedHistory[i], wantHistory[i])
+		}
+	}
+}
+
+func TestWriteOpenAIError_ReturnsWriteError(t *testing.T) {
+	err := writeOpenAIError(&failingResponseWriter{}, http.StatusBadRequest, "bad request", "invalid_request_error", "bad_request")
+	if err == nil {
+		t.Fatal("writeOpenAIError() error = nil, want non-nil")
+	}
+}

pkg/config/config.go

@@ -478,6 +478,7 @@ type OpenAIAPIConfig struct {
 	Enabled      bool     `json:"enabled" env:"PICOCLAW_CHANNELS_OPENAI_API_ENABLED"`
 	Port         int      `json:"port"    env:"PICOCLAW_CHANNELS_OPENAI_API_PORT"`
 	APIKey       string   `json:"api_key" env:"PICOCLAW_CHANNELS_OPENAI_API_API_KEY"`
+	AllowOrigins []string `json:"allow_origins,omitempty"`
 }
 
 type IRCConfig struct {

pkg/config/defaults.go

@@ -179,6 +179,7 @@ func DefaultConfig() *Config {
 				Enabled:      false,
 				Port:         18794,
 				APIKey:       "",
+				AllowOrigins: []string{"localhost"},
 			},
 		},
 		Providers: ProvidersConfig{