diff --git a/internal/translator/antigravity/openai/chat-completions/antigravity_openai_response.go b/internal/translator/antigravity/openai/chat-completions/antigravity_openai_response.go
index c70daaf2..c392b625 100644
--- a/internal/translator/antigravity/openai/chat-completions/antigravity_openai_response.go
+++ b/internal/translator/antigravity/openai/chat-completions/antigravity_openai_response.go
@@ -105,14 +105,19 @@ func ConvertAntigravityResponseToOpenAI(_ context.Context, _ string, originalReq
 			partTextResult := partResult.Get("text")
 			functionCallResult := partResult.Get("functionCall")
 			thoughtSignatureResult := partResult.Get("thoughtSignature")
+			if !thoughtSignatureResult.Exists() {
+				thoughtSignatureResult = partResult.Get("thought_signature")
+			}
 			inlineDataResult := partResult.Get("inlineData")
 			if !inlineDataResult.Exists() {
 				inlineDataResult = partResult.Get("inline_data")
 			}
 
-			// Handle thoughtSignature - this is encrypted reasoning content that should not be exposed to the client
-			if thoughtSignatureResult.Exists() && thoughtSignatureResult.String() != "" {
-				// Skip thoughtSignature processing - it's internal encrypted data
+			hasThoughtSignature := thoughtSignatureResult.Exists() && thoughtSignatureResult.String() != ""
+			hasContentPayload := partTextResult.Exists() || functionCallResult.Exists() || inlineDataResult.Exists()
+
+			// Ignore encrypted thoughtSignature but keep any actual content in the same part.
+			if hasThoughtSignature && !hasContentPayload {
 				continue
 			}
 
diff --git a/internal/translator/gemini-cli/openai/chat-completions/gemini-cli_openai_response.go b/internal/translator/gemini-cli/openai/chat-completions/gemini-cli_openai_response.go
index 73df7a7c..d4084ec6 100644
--- a/internal/translator/gemini-cli/openai/chat-completions/gemini-cli_openai_response.go
+++ b/internal/translator/gemini-cli/openai/chat-completions/gemini-cli_openai_response.go
@@ -105,14 +105,19 @@ func ConvertCliResponseToOpenAI(_ context.Context, _ string, originalRequestRawJ
 			partTextResult := partResult.Get("text")
 			functionCallResult := partResult.Get("functionCall")
 			thoughtSignatureResult := partResult.Get("thoughtSignature")
+			if !thoughtSignatureResult.Exists() {
+				thoughtSignatureResult = partResult.Get("thought_signature")
+			}
 			inlineDataResult := partResult.Get("inlineData")
 			if !inlineDataResult.Exists() {
 				inlineDataResult = partResult.Get("inline_data")
 			}
 
-			// Handle thoughtSignature - this is encrypted reasoning content that should not be exposed to the client
-			if thoughtSignatureResult.Exists() && thoughtSignatureResult.String() != "" {
-				// Skip thoughtSignature processing - it's internal encrypted data
+			hasThoughtSignature := thoughtSignatureResult.Exists() && thoughtSignatureResult.String() != ""
+			hasContentPayload := partTextResult.Exists() || functionCallResult.Exists() || inlineDataResult.Exists()
+
+			// Ignore encrypted thoughtSignature but keep any actual content in the same part.
+			if hasThoughtSignature && !hasContentPayload {
 				continue
 			}
 
diff --git a/internal/translator/gemini/openai/chat-completions/gemini_openai_response.go b/internal/translator/gemini/openai/chat-completions/gemini_openai_response.go
index 24112f0f..4f0b01e7 100644
--- a/internal/translator/gemini/openai/chat-completions/gemini_openai_response.go
+++ b/internal/translator/gemini/openai/chat-completions/gemini_openai_response.go
@@ -116,8 +116,11 @@ func ConvertGeminiResponseToOpenAI(_ context.Context, _ string, originalRequestR
 				thoughtSignatureResult = partResult.Get("thought_signature")
 			}
 
-			// Skip thoughtSignature parts (encrypted reasoning not exposed downstream).
-			if thoughtSignatureResult.Exists() && thoughtSignatureResult.String() != "" {
+			hasThoughtSignature := thoughtSignatureResult.Exists() && thoughtSignatureResult.String() != ""
+			hasContentPayload := partTextResult.Exists() || functionCallResult.Exists() || inlineDataResult.Exists()
+
+			// Skip pure thoughtSignature parts but keep any actual payload in the same part.
+			if hasThoughtSignature && !hasContentPayload {
 				continue
 			}