Fix:Support both JSON array format and comma-separated values from user headers

litellm/llms/bedrock/common_utils.py

@@ -797,7 +797,7 @@ class BedrockEventStreamDecoderBase:
 def get_anthropic_beta_from_headers(headers: dict) -> List[str]:
     """
     Extract anthropic-beta header values and convert them to a list.
-    Supports comma-separated values from user headers.
+    Supports both JSON array format and comma-separated values from user headers.
 
     Used by both converse and invoke transformations for consistent handling
     of anthropic-beta headers that should be passed to AWS Bedrock.
@@ -812,8 +812,25 @@ def get_anthropic_beta_from_headers(headers: dict) -> List[str]:
     if not anthropic_beta_header:
         return []
 
-    # Split comma-separated values and strip whitespace
-    return [beta.strip() for beta in anthropic_beta_header.split(",")]
+    # If it's already a list, return it
+    if isinstance(anthropic_beta_header, list):
+        return anthropic_beta_header
+    
+    # Try to parse as JSON array first (e.g., '["interleaved-thinking-2025-05-14", "claude-code-20250219"]')
+    if isinstance(anthropic_beta_header, str):
+        anthropic_beta_header = anthropic_beta_header.strip()
+        if anthropic_beta_header.startswith("[") and anthropic_beta_header.endswith("]"):
+            try:
+                parsed = json.loads(anthropic_beta_header)
+                if isinstance(parsed, list):
+                    return [str(beta).strip() for beta in parsed]
+            except json.JSONDecodeError:
+                pass  # Fall through to comma-separated parsing
+        
+        # Fall back to comma-separated values
+        return [beta.strip() for beta in anthropic_beta_header.split(",")]
+    
+    return []
 
 
 class CommonBatchFilesUtils: