fix(mcp): Nest MCP spans under HTTP transactions

sentry_sdk/integrations/mcp.py

@@ -21,6 +21,7 @@
 try:
     from mcp.server.lowlevel import Server  # type: ignore[import-not-found]
     from mcp.server.lowlevel.server import request_ctx  # type: ignore[import-not-found]
+    from mcp.server.streamable_http import StreamableHTTPServerTransport  # type: ignore[import-not-found]
 except ImportError:
     raise DidNotEnable("MCP SDK not installed")
 
@@ -31,7 +32,9 @@
 
 
 if TYPE_CHECKING:
-    from typing import Any, Callable, Optional
+    from typing import Any, Callable, Optional, Tuple
+
+    from starlette.types import Receive, Scope, Send  # type: ignore[import-not-found]
 
 
 class MCPIntegration(Integration):
@@ -54,11 +57,34 @@ def setup_once() -> None:
         Patches MCP server classes to instrument handler execution.
         """
         _patch_lowlevel_server()
+        _patch_handle_request()
 
         if FastMCP is not None:
             _patch_fastmcp()
 
 
+def _get_active_http_scopes() -> (
+    "Optional[Tuple[Optional[sentry_sdk.Scope], Optional[sentry_sdk.Scope]]]"
+):
+    try:
+        ctx = request_ctx.get()
+    except LookupError:
+        return None
+
+    if (
+        ctx is None
+        or not hasattr(ctx, "request")
+        or ctx.request is None
+        or "state" not in ctx.request.scope
+    ):
+        return None
+
+    return (
+        ctx.request.scope["state"].get("sentry_sdk.current_scope"),
+        ctx.request.scope["state"].get("sentry_sdk.isolation_scope"),
+    )
+
+
 def _get_request_context_data() -> "tuple[Optional[str], Optional[str], str]":
     """
     Extract request ID, session ID, and MCP transport type from the request context.
@@ -381,56 +407,67 @@ async def _async_handler_wrapper(
         result_data_key,
     ) = _prepare_handler_data(handler_type, original_args, original_kwargs)
 
-    # Start span and execute
-    with get_start_span_function()(
-        op=OP.MCP_SERVER,
-        name=span_name,
-        origin=MCPIntegration.origin,
-    ) as span:
-        # Get request ID, session ID, and transport from context
-        request_id, session_id, mcp_transport = _get_request_context_data()
+    scopes = _get_active_http_scopes()
 
-        # Set input span data
-        _set_span_input_data(
-            span,
-            handler_name,
-            span_data_key,
-            mcp_method_name,
-            arguments,
-            request_id,
-            session_id,
-            mcp_transport,
-        )
+    if scopes is None:
+        current_scope = None
+        isolation_scope = None
+    else:
+        current_scope, isolation_scope = scopes
 
-        # For resources, extract and set protocol
-        if handler_type == "resource":
-            if original_args:
-                uri = original_args[0]
-            else:
-                uri = original_kwargs.get("uri")
+    # Get request ID, session ID, and transport from context
+    request_id, session_id, mcp_transport = _get_request_context_data()
 
-            protocol = None
-            if hasattr(uri, "scheme"):
-                protocol = uri.scheme
-            elif handler_name and "://" in handler_name:
-                protocol = handler_name.split("://")[0]
-            if protocol:
-                span.set_data(SPANDATA.MCP_RESOURCE_PROTOCOL, protocol)
-
-        try:
-            # Execute the async handler
-            if self is not None:
-                original_args = (self, *original_args)
-            result = await func(*original_args, **original_kwargs)
-        except Exception as e:
-            # Set error flag for tools
-            if handler_type == "tool":
-                span.set_data(SPANDATA.MCP_TOOL_RESULT_IS_ERROR, True)
-            sentry_sdk.capture_exception(e)
-            raise
+    # Start span and execute
+    with sentry_sdk.scope.use_isolation_scope(isolation_scope):
+        with sentry_sdk.scope.use_scope(current_scope):
+            with sentry_sdk.start_span(
+                op=OP.MCP_SERVER,
+                name=span_name,
+                origin=MCPIntegration.origin,
+            ) as span:
+                # Set input span data
+                _set_span_input_data(
+                    span,
+                    handler_name,
+                    span_data_key,
+                    mcp_method_name,
+                    arguments,
+                    request_id,
+                    session_id,
+                    mcp_transport,
+                )
+
+                # For resources, extract and set protocol
+                if handler_type == "resource":
+                    if original_args:
+                        uri = original_args[0]
+                    else:
+                        uri = original_kwargs.get("uri")
+
+                    protocol = None
+                    if hasattr(uri, "scheme"):
+                        protocol = uri.scheme
+                    elif handler_name and "://" in handler_name:
+                        protocol = handler_name.split("://")[0]
+                    if protocol:
+                        span.set_data(SPANDATA.MCP_RESOURCE_PROTOCOL, protocol)
+
+                try:
+                    # Execute the async handler
+                    if self is not None:
+                        original_args = (self, *original_args)
+                    result = await func(*original_args, **original_kwargs)
+                except Exception as e:
+                    # Set error flag for tools
+                    if handler_type == "tool":
+                        span.set_data(SPANDATA.MCP_TOOL_RESULT_IS_ERROR, True)
+                    sentry_sdk.capture_exception(e)
+                    raise
+
+                _set_span_output_data(span, result, result_data_key, handler_type)
 
-        _set_span_output_data(span, result, result_data_key, handler_type)
-        return result
+    return result
 
 
 def _sync_handler_wrapper(
@@ -618,6 +655,27 @@ def patched_read_resource(
     Server.read_resource = patched_read_resource
 
 
+def _patch_handle_request() -> None:
+    original_handle_request = StreamableHTTPServerTransport.handle_request
+
+    @wraps(original_handle_request)
+    async def patched_handle_request(
+        self: "StreamableHTTPServerTransport",
+        scope: "Scope",
+        receive: "Receive",
+        send: "Send",
+    ) -> None:
+        scope.setdefault("state", {})["sentry_sdk.isolation_scope"] = (
+            sentry_sdk.get_isolation_scope()
+        )
+        scope.setdefault("state", {})["sentry_sdk.current_scope"] = (
+            sentry_sdk.get_current_scope()
+        )
+        await original_handle_request(self, scope, receive, send)
+
+    StreamableHTTPServerTransport.handle_request = patched_handle_request
+
+
 def _patch_fastmcp() -> None:
     """
     Patches the standalone fastmcp package's FastMCP class.

sentry_sdk/scope.py

@@ -100,6 +100,7 @@
 
     F = TypeVar("F", bound=Callable[..., Any])
     T = TypeVar("T")
+    S = TypeVar("S", bound=Optional["Scope"])
 
 
 # Holds data that will be added to **all** events sent by this process.
@@ -1786,7 +1787,7 @@ def new_scope() -> "Generator[Scope, None, None]":
 
 
 @contextmanager
-def use_scope(scope: "Scope") -> "Generator[Scope, None, None]":
+def use_scope(scope: "S") -> "Generator[S, None, None]":
     """
     .. versionadded:: 2.0.0
 
@@ -1808,6 +1809,10 @@ def use_scope(scope: "Scope") -> "Generator[Scope, None, None]":
         sentry_sdk.capture_message("hello, again") # will NOT include `color` tag.
 
     """
+    if scope is None:
+        yield scope
+        return
+
     # set given scope as current scope
     token = _current_scope.set(scope)
 
@@ -1871,7 +1876,7 @@ def isolation_scope() -> "Generator[Scope, None, None]":
 
 
 @contextmanager
-def use_isolation_scope(isolation_scope: "Scope") -> "Generator[Scope, None, None]":
+def use_isolation_scope(isolation_scope: "S") -> "Generator[S, None, None]":
     """
     .. versionadded:: 2.0.0
 
@@ -1892,6 +1897,10 @@ def use_isolation_scope(isolation_scope: "Scope") -> "Generator[Scope, None, Non
         sentry_sdk.capture_message("hello, again") # will NOT include `color` tag.
 
     """
+    if isolation_scope is None:
+        yield isolation_scope
+        return
+
     # fork current scope
     current_scope = Scope.get_current_scope()
     forked_current_scope = current_scope.fork()

tests/integrations/fastmcp/test_fastmcp.py

@@ -262,6 +262,7 @@ class MockHTTPRequest:
     def __init__(self, session_id=None, transport="http"):
         self.headers = {}
         self.query_params = {}
+        self.scope = {}
 
         if transport == "sse":
             # SSE transport uses query parameter