Align OAuth transform with OpenCode instructions

backend/internal/service/openai_codex_transform.go

@@ -13,11 +13,12 @@ import (
 )
 
 const (
-	codexReleaseAPIURL  = "https://api.github.com/repos/openai/codex/releases/latest"
-	codexReleaseHTMLURL = "https://github.com/openai/codex/releases/latest"
-	codexPromptURLFmt   = "https://raw.githubusercontent.com/openai/codex/%s/codex-rs/core/%s"
-	opencodeCodexURL    = "https://raw.githubusercontent.com/anomalyco/opencode/dev/packages/opencode/src/session/prompt/codex.txt"
-	codexCacheTTL       = 15 * time.Minute
+	codexReleaseAPIURL     = "https://api.github.com/repos/openai/codex/releases/latest"
+	codexReleaseHTMLURL    = "https://github.com/openai/codex/releases/latest"
+	codexPromptURLFmt      = "https://raw.githubusercontent.com/openai/codex/%s/codex-rs/core/%s"
+	opencodeCodexURL       = "https://raw.githubusercontent.com/anomalyco/opencode/dev/packages/opencode/src/session/prompt/codex.txt"
+	opencodeCodexHeaderURL = "https://raw.githubusercontent.com/anomalyco/opencode/dev/packages/opencode/src/session/prompt/codex_header.txt"
+	codexCacheTTL          = 15 * time.Minute
 )
 
 type codexModelFamily string
@@ -177,7 +178,7 @@ func applyCodexOAuthTransform(reqBody map[string]any) codexTransformResult {
 		result.PromptCacheKey = strings.TrimSpace(v)
 	}
 
-	instructions := strings.TrimSpace(getCodexInstructions(normalizedModel))
+	instructions := strings.TrimSpace(getOpenCodeCodexHeader())
 	existingInstructions, _ := reqBody["instructions"].(string)
 	existingInstructions = strings.TrimSpace(existingInstructions)
 
@@ -408,13 +409,13 @@ func parseReleaseTagFromHTML(html string) (string, error) {
 	return "", fmt.Errorf("release tag not found")
 }
 
-func getOpenCodeCodexPrompt() string {
+func getOpenCodeCachedPrompt(url, cacheFileName, metaFileName string) string {
 	cacheDir := codexCachePath("")
 	if cacheDir == "" {
 		return ""
 	}
-	cacheFile := filepath.Join(cacheDir, "opencode-codex.txt")
-	metaFile := filepath.Join(cacheDir, "opencode-codex-meta.json")
+	cacheFile := filepath.Join(cacheDir, cacheFileName)
+	metaFile := filepath.Join(cacheDir, metaFileName)
 
 	var cachedContent string
 	if content, ok := readFile(cacheFile); ok {
@@ -428,7 +429,7 @@ func getOpenCodeCodexPrompt() string {
 		}
 	}
 
-	content, etag, status, err := fetchWithETag(opencodeCodexURL, meta.ETag)
+	content, etag, status, err := fetchWithETag(url, meta.ETag)
 	if err == nil && status == http.StatusNotModified && cachedContent != "" {
 		return cachedContent
 	}
@@ -446,6 +447,14 @@ func getOpenCodeCodexPrompt() string {
 	return cachedContent
 }
 
+func getOpenCodeCodexPrompt() string {
+	return getOpenCodeCachedPrompt(opencodeCodexURL, "opencode-codex.txt", "opencode-codex-meta.json")
+}
+
+func getOpenCodeCodexHeader() string {
+	return getOpenCodeCachedPrompt(opencodeCodexHeaderURL, "opencode-codex-header.txt", "opencode-codex-header-meta.json")
+}
+
 func filterCodexInput(input []any) []any {
 	filtered := make([]any, 0, len(input))
 	for _, item := range input {

backend/internal/service/openai_gateway_service.go

@@ -580,7 +580,7 @@ func (s *OpenAIGatewayService) Forward(ctx context.Context, c *gin.Context, acco
 	}
 
 	// Build upstream request
-	upstreamReq, err := s.buildUpstreamRequest(ctx, c, account, body, token, reqStream, promptCacheKey)
+	upstreamReq, err := s.buildUpstreamRequest(ctx, c, account, body, token, reqStream, promptCacheKey, isCodexCLI)
 	if err != nil {
 		return nil, err
 	}
@@ -641,7 +641,7 @@ func (s *OpenAIGatewayService) Forward(ctx context.Context, c *gin.Context, acco
 	}, nil
 }
 
-func (s *OpenAIGatewayService) buildUpstreamRequest(ctx context.Context, c *gin.Context, account *Account, body []byte, token string, isStream bool, promptCacheKey string) (*http.Request, error) {
+func (s *OpenAIGatewayService) buildUpstreamRequest(ctx context.Context, c *gin.Context, account *Account, body []byte, token string, isStream bool, promptCacheKey string, isCodexCLI bool) (*http.Request, error) {
 	// Determine target URL based on account type
 	var targetURL string
 	switch account.Type {
@@ -694,7 +694,11 @@ func (s *OpenAIGatewayService) buildUpstreamRequest(ctx context.Context, c *gin.
 	}
 	if account.Type == AccountTypeOAuth {
 		req.Header.Set("OpenAI-Beta", "responses=experimental")
-		req.Header.Set("originator", "codex_cli_rs")
+		if isCodexCLI {
+			req.Header.Set("originator", "codex_cli_rs")
+		} else {
+			req.Header.Set("originator", "opencode")
+		}
 		req.Header.Set("accept", "text/event-stream")
 		if promptCacheKey != "" {
 			req.Header.Set("conversation_id", promptCacheKey)

backend/internal/service/openai_gateway_service_test.go

@@ -220,7 +220,7 @@ func TestOpenAIInvalidBaseURLWhenAllowlistDisabled(t *testing.T) {
 		Credentials: map[string]any{"base_url": "://invalid-url"},
 	}
 
-	_, err := svc.buildUpstreamRequest(c.Request.Context(), c, account, []byte("{}"), "token", false, "")
+	_, err := svc.buildUpstreamRequest(c.Request.Context(), c, account, []byte("{}"), "token", false, "", false)
 	if err == nil {
 		t.Fatalf("expected error for invalid base_url when allowlist disabled")
 	}