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A2A _serialize_value() corrupts JSON-native metadata types to strings #5183
Description
Bug Description
_serialize_value() in from_adk_event.py falls through to str() for JSON-native Python types (dict, list, bool, int, float), corrupting structured metadata values into their string representations during A2A event conversion.
Steps to Reproduce
from google.adk.a2a.converters.from_adk_event import _serialize_value
metadata = {"retry": True, "max_attempts": 3, "tags": ["alpha", "beta"]}
result = _serialize_value(metadata)
print(type(result), result)
# Actual: <class 'str'> "{'retry': True, 'max_attempts': 3, 'tags': ['alpha', 'beta']}"
# Expected: <class 'dict'> {'retry': True, 'max_attempts': 3, 'tags': ['alpha', 'beta']}Expected Behavior
JSON-native types (dict, list, str, bool, int, float) should be preserved as-is since they are already valid JSON values, not converted to strings.
Actual Behavior
All non-Pydantic values that aren't None are passed through str(), which corrupts structured data into Python repr strings.
Activity
enjoykumawat commentedon Apr 7, 2026
I'd like to work on this. The fix is to pass through JSON-native types (dict, list, int, float, bool) as-is in
_serialize_value()instead of stringifying them. Will submit a PR shortly.fix: preserve JSON-native types in A2A _serialize_value()
fix: preserve JSON-native types in A2A _serialize_value()
fix: preserve JSON-native types in A2A _serialize_value()
sanketpatil06 commentedon Apr 10, 2026
Hi @YizukiAme,
Thank you for reporting this issue. I have reproduced it on my end and can confirm the metadata serialization behavior you are seeing.
Additionally, thank you both, @YizukiAme and @enjoykumawat, for submitting pull requests. Our team is currently reviewing both PRs to determine the best approach for a fix.
We really appreciate your contributions.
enjoykumawat commentedon Apr 10, 2026
Thanks for the update @sanketpatil06! Happy to hear the team is reviewing both approaches.
I'm happy to coordinate with @YizukiAme — if their implementation fits better with the codebase direction, feel free to close #5200. The goal is just to get the fix in.
If there's anything specific you'd like me to adjust on my PR to make it easier to evaluate, just let me know.
fix: preserve JSON-native types in A2A _serialize_value()
fix: preserve JSON-native types in A2A _serialize_value()