refactor(formats): remove detect_format from strategy interface and check sentinels in converter

Author: gspencergoog

agent_sdks/python/a2ui_agent/src/a2ui/adk/a2a/part_converter.py

@@ -120,9 +120,7 @@ def convert(self, part: genai_types.Part) -> list[a2a_types.Part]:
 
             if function_response.response:
                 result = function_response.response.get("result")
-                if isinstance(result, str) and self._format_strategy.detect_format(
-                    result
-                ):
+                if isinstance(result, str) and "<a2ui" in result:
                     return parse_response_to_parts(
                         result,
                         validator=self._catalog.validator,
@@ -140,7 +138,7 @@ def convert(self, part: genai_types.Part) -> list[a2a_types.Part]:
 
         # 3. Handle Text-based A2UI (TextPart)
         if text := part.text:
-            if self._format_strategy.detect_format(text):
+            if "<a2ui" in text:
                 return parse_response_to_parts(
                     text,
                     validator=self._catalog.validator,

agent_sdks/python/a2ui_agent/src/a2ui/formats/__init__.py

@@ -70,10 +70,6 @@ def wrap_decompiled_blocks(self, blocks: List[str]) -> str:
         """Wraps decompiled code blocks in format-specific tags and code block wrappers."""
         pass
 
-    def detect_format(self, content: str) -> bool:
-        """Returns True if the content contains this format's sentinel/payload tags."""
-        return "<a2ui" in content
-
 
 class PromptGenerator:
     """Helper to assemble prompt instructions and transform examples."""