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fix: Add support for MCP 2 re-exported types #360

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Merged
Gavin Aguiar (gavin-aguiar) merged 1 commit into from
Jul 31, 2026
Merged

fix: Add support for MCP 2 re-exported types #360

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82 changes: 12 additions & 70 deletions azure/functions/decorators/function_app.py
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Original file line number Diff line number Diff line change
Expand Up @@ -56,7 +56,8 @@
from .retry_policy import RetryPolicy
from .function_name import FunctionName
from .warmup import WarmUpTrigger
from ..mcp import MCPToolContext, _is_mcp_call_tool_result, _is_mcp_sdk_type
from ..mcp import (MCPToolContext, _is_mcp_call_tool_result,
_is_mcp_sdk_type, _is_mcp_sdk_type_annotation)
from .._http_asgi import AsgiMiddleware
from .._http_wsgi import WsgiMiddleware, Context
from azure.functions.decorators.mysql import MySqlInput, MySqlOutput, \
Expand Down Expand Up @@ -1684,16 +1685,8 @@ def decorator(fb: FunctionBuilder) -> FunctionBuilder:
is_mcp_content = False
is_mcp_sdk_type = False

# Try to detect official MCP SDK types by checking module
try:
if isinstance(return_annotation, type):
# Check if the type is from the mcp.types module
if hasattr(return_annotation, '__module__'):
module = return_annotation.__module__
if module and (module.startswith('mcp.types') or module == 'mcp.types'):
is_mcp_sdk_type = True
except (ImportError, TypeError, AttributeError):
pass
is_mcp_sdk_type = _is_mcp_sdk_type_annotation(
return_annotation)

# Check for @mcp_content decorated classes
try:
Expand All @@ -1709,46 +1702,6 @@ def decorator(fb: FunctionBuilder) -> FunctionBuilder:
origin = typing.get_origin(return_annotation)
args = typing.get_args(return_annotation)

# Check for official MCP SDK types in lists
if origin in (list, List):
# For List[T], check if T is an MCP type
try:
if len(args) > 0:
list_item_type = args[0]
# Check if it's a direct MCP type
if isinstance(list_item_type, type):
if hasattr(list_item_type, '__module__'):
module = list_item_type.__module__
if (module
and (module.startswith('mcp.types')
or module == 'mcp.types')):
is_mcp_sdk_type = True
# Check if it's a Union of MCP types
elif hasattr(list_item_type, '__origin__'):
union_origin = typing.get_origin(
list_item_type)
if union_origin is Union:
union_args = typing.get_args(
list_item_type)
for union_arg in union_args:
if (isinstance(union_arg, type)
and union_arg is not # noqa
type(None)):
if hasattr(union_arg,
'__module__'):
module = (
union_arg.__module__)
if (module
and (module.startswith(
'mcp.types')
or module
== 'mcp.types')):
is_mcp_sdk_type = True
break
except (ImportError, TypeError, AttributeError,
IndexError):
pass

# Check for Optional[T] where T is an MCP type
if origin is Union:
for arg in args:
Expand All @@ -1762,20 +1715,6 @@ def decorator(fb: FunctionBuilder) -> FunctionBuilder:
except TypeError:
pass

# Check for MCP SDK types in Union
try:
if isinstance(arg, type):
# Check module for mcp.types
if hasattr(arg, '__module__'):
module = arg.__module__
if (module
and (module.startswith('mcp.types')
or module == 'mcp.types')):
is_mcp_sdk_type = True
break
except (ImportError, TypeError, AttributeError):
pass

# Auto-enable use_result_schema for MCP types
if is_mcp_content or is_mcp_sdk_type:
auto_use_result_schema = True
Expand Down Expand Up @@ -1840,15 +1779,17 @@ async def wrapper(context: str, *args, **kwargs):
# Serialize using model_dump() for Pydantic models
if hasattr(result, 'model_dump'):
result_dict = result.model_dump(
mode='json', exclude_none=True)
mode='json', exclude_none=True, by_alias=True)
elif hasattr(result, 'dict'):
result_dict = result.dict(exclude_none=True)
result_dict = result.dict(
exclude_none=True, by_alias=True)
else:
# Fallback: convert to dict manually
result_dict = {
'content': [
block.model_dump(
mode='json', exclude_none=True)
mode='json', exclude_none=True,
by_alias=True)
if hasattr(block, 'model_dump')
else dict(block)
for block in result.content
Expand Down Expand Up @@ -1907,10 +1848,11 @@ async def wrapper(context: str, *args, **kwargs):
elif _is_mcp_sdk_type(result):
if hasattr(result, 'model_dump'):
result_dict = result.model_dump(
mode='json', exclude_none=True)
mode='json', exclude_none=True, by_alias=True)
result_json = json.dumps(result_dict)
elif hasattr(result, 'dict'):
result_dict = result.dict(exclude_none=True)
result_dict = result.dict(
exclude_none=True, by_alias=True)
result_json = json.dumps(result_dict)
else:
result_dict = result.__dict__
Expand Down
58 changes: 45 additions & 13 deletions azure/functions/mcp.py
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Original file line number Diff line number Diff line change
Expand Up @@ -36,14 +36,42 @@ def _is_mcp_sdk_type(obj: Any) -> bool:
_mcp_types = None
return False

# Check if the object's class is from the mcp.types module
obj_type = type(obj)
if hasattr(obj_type, '__module__'):
module = obj_type.__module__
# Check if it's from mcp.types or any mcp submodule
if module and (module.startswith('mcp.types') or module == 'mcp.types'):
return _is_mcp_sdk_type_annotation(type(obj))


def _is_mcp_sdk_type_annotation(annotation: Any) -> bool:
"""Check if a return annotation is an official MCP SDK type.

MCP SDK 1.x types are defined in ``mcp.types``. MCP SDK 2.x re-exports
types defined in ``mcp_types`` from that same public module.
"""
if isinstance(annotation, type):
module = getattr(annotation, '__module__', None)
if module and module.startswith('mcp.types'):
return True

if module and (module == 'mcp_types'
or module.startswith('mcp_types.')):
global _MCP_SDK_AVAILABLE, _mcp_types
if not _MCP_SDK_AVAILABLE or _mcp_types is None:
try:
from mcp import types as _mcp_types
_MCP_SDK_AVAILABLE = True
except ImportError:
_mcp_types = None
return False

return any(exported is annotation
for exported in vars(_mcp_types).values())

return False

origin = typing.get_origin(annotation)
if origin in (list, typing.Union):
return any(arg is not type(None)
and _is_mcp_sdk_type_annotation(arg)
for arg in typing.get_args(annotation))

return False


Expand Down Expand Up @@ -74,9 +102,10 @@ def _serialize_content_block(block: Any) -> dict:
if _is_mcp_sdk_type(block):
# MCP SDK types should be JSON-serializable
if hasattr(block, 'model_dump'):
return block.model_dump(mode='json', exclude_none=True)
return block.model_dump(
mode='json', exclude_none=True, by_alias=True)
elif hasattr(block, 'dict'):
return block.dict(exclude_none=True)
return block.dict(exclude_none=True, by_alias=True)

# If it's a dataclass (e.g., @mcp_content decorated)
if is_dataclass(block) and not isinstance(block, type):
Expand Down Expand Up @@ -200,19 +229,22 @@ def encode(cls, obj: typing.Any, *,
elif _is_mcp_call_tool_result(obj):
# Serialize the MCP SDK's CallToolResult
if hasattr(obj, 'model_dump'):
result_dict = obj.model_dump(mode='json', exclude_none=True)
result_dict = obj.model_dump(
mode='json', exclude_none=True, by_alias=True)
elif hasattr(obj, 'dict'):
result_dict = obj.dict(exclude_none=True)
result_dict = obj.dict(exclude_none=True, by_alias=True)
else:
# Fallback: try to access attributes directly
content_blocks = [_serialize_content_block(block)
for block in obj.content]
result_dict = {
'content': content_blocks if hasattr(obj, 'content') else [],
}
if (hasattr(obj, 'structured_content')
and obj.structured_content is not None):
result_dict['structuredContent'] = obj.structured_content
structured_content = getattr(
obj, 'structuredContent',
getattr(obj, 'structured_content', None))
if structured_content is not None:
result_dict['structuredContent'] = structured_content
result_json = json.dumps(result_dict)
return meta.Datum(type='string', value=result_json)

Expand Down
11 changes: 10 additions & 1 deletion tests/decorators/test_mcp.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,8 @@
MCPResourceTrigger,
MCPPromptTrigger)
from azure.functions.mcp import (_MCPToolTriggerConverter,
MCPResourceTriggerConverter)
MCPResourceTriggerConverter,
_is_mcp_sdk_type)
from azure.functions.meta import Datum
from mcp.types import (
ResourceLink,
Expand All @@ -27,6 +28,14 @@


class TestMCP(unittest.TestCase):
def test_legacy_mcp_type_module_remains_supported(self):
class LegacyMCPType:
pass

LegacyMCPType.__module__ = "mcp.types"

self.assertTrue(_is_mcp_sdk_type(LegacyMCPType()))

def test_mcp_tool_trigger_valid_creation(self):
trigger = _MCPToolTrigger(
name="context",
Expand Down
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