Control async op expiry by resolved_at, not created_at

Author: LucaButBoring

src/mcp/shared/async_operations.py

@@ -25,7 +25,7 @@ class ClientAsyncOperation:
     @property
     def is_expired(self) -> bool:
         """Check if operation has expired based on keepAlive."""
-        return time.time() > (self.created_at + self.keep_alive)
+        return time.time() > (self.created_at + self.keep_alive * 2)  # Give some buffer before expiration
 
 
 @dataclass
@@ -38,15 +38,18 @@ class ServerAsyncOperation:
     status: AsyncOperationStatus
     created_at: float
     keep_alive: int
+    resolved_at: float | None = None
     session_id: str | None = None
     result: types.CallToolResult | None = None
     error: str | None = None
 
     @property
     def is_expired(self) -> bool:
         """Check if operation has expired based on keepAlive."""
+        if not self.resolved_at:
+            return False
         if self.status in ("completed", "failed", "canceled"):
-            return time.time() > (self.created_at + self.keep_alive)
+            return time.time() > (self.resolved_at + self.keep_alive)
         return False
 
     @property
@@ -197,6 +200,7 @@ def complete_operation(self, token: str, result: types.CallToolResult) -> bool:
 
         operation.status = "completed"
         operation.result = result
+        operation.resolved_at = time.time()
         return True
 
     def fail_operation(self, token: str, error: str) -> bool:
@@ -211,6 +215,7 @@ def fail_operation(self, token: str, error: str) -> bool:
 
         operation.status = "failed"
         operation.error = error
+        operation.resolved_at = time.time()
         return True
 
     def get_operation_result(self, token: str) -> types.CallToolResult | None:

tests/server/test_lowlevel_async_operations.py

@@ -55,7 +55,7 @@ async def check_status_handler(token: str) -> types.GetOperationStatusResult:
         manager.complete_operation(operation.token, types.CallToolResult(content=[]))
 
         # Make it expired
-        operation.created_at = time.time() - 2
+        operation.resolved_at = time.time() - 2
 
         expired_request = types.GetOperationStatusRequest(params=types.GetOperationStatusParams(token=operation.token))
 
@@ -164,7 +164,7 @@ async def get_result_handler(token: str) -> types.GetOperationPayloadResult:
         manager.complete_operation(operation.token, types.CallToolResult(content=[]))
 
         # Make it expired
-        operation.created_at = time.time() - 2
+        operation.resolved_at = time.time() - 2
 
         expired_request = types.GetOperationPayloadRequest(
             params=types.GetOperationPayloadParams(token=operation.token)

tests/shared/test_async_operations.py

@@ -178,7 +178,7 @@ def test_expiration_and_cleanup(self):
         # Complete both and make first expired
         for op in [short_op, long_op]:
             manager.complete_operation(op.token, Mock())
-        short_op.created_at = time.time() - 2
+        short_op.resolved_at = time.time() - 2
 
         # Test expiration detection
         assert short_op.is_expired and not long_op.is_expired
@@ -207,7 +207,7 @@ def test_concurrent_operations(self):
         for i in range(25):
             manager.complete_operation(operations[i].token, Mock())
             operations[i].keep_alive = 1
-            operations[i].created_at = time.time() - 2
+            operations[i].resolved_at = time.time() - 2
 
         # Cleanup should remove expired operations
         removed_count = manager.cleanup_expired_operations()
@@ -286,8 +286,8 @@ def test_terminal_and_expiration_logic(self):
 
         completed_status: AsyncOperationStatus = "completed"
         operation.status = completed_status
-        operation.created_at = now - 1800  # 30 minutes ago
+        operation.resolved_at = now - 1800  # 30 minutes ago
         assert not operation.is_expired  # Within keepAlive
 
-        operation.created_at = now - 7200  # 2 hours ago
+        operation.resolved_at = now - 7200  # 2 hours ago
         assert operation.is_expired  # Past keepAlive