diff --git a/python/restate/discovery.py b/python/restate/discovery.py
index b6a0d95..0bd22dc 100644
--- a/python/restate/discovery.py
+++ b/python/restate/discovery.py
@@ -346,17 +346,19 @@ def compute_discovery(endpoint: RestateEndpoint, discovered_as: typing.Literal["
                     description=handler.description,
                     metadata=handler.metadata,
                     inactivityTimeout=int(handler.inactivity_timeout.total_seconds() * 1000)
-                    if handler.inactivity_timeout
+                    if handler.inactivity_timeout is not None
+                    else None,
+                    abortTimeout=int(handler.abort_timeout.total_seconds() * 1000)
+                    if handler.abort_timeout is not None
                     else None,
-                    abortTimeout=int(handler.abort_timeout.total_seconds() * 1000) if handler.abort_timeout else None,
                     journalRetention=int(handler.journal_retention.total_seconds() * 1000)
-                    if handler.journal_retention
+                    if handler.journal_retention is not None
                     else None,
                     idempotencyRetention=int(handler.idempotency_retention.total_seconds() * 1000)
-                    if handler.idempotency_retention
+                    if handler.idempotency_retention is not None
                     else None,
                     workflowCompletionRetention=int(handler.workflow_retention.total_seconds() * 1000)
-                    if handler.workflow_retention
+                    if handler.workflow_retention is not None
                     else None,
                     enableLazyState=handler.enable_lazy_state,
                     ingressPrivate=handler.ingress_private,
@@ -394,14 +396,16 @@ def compute_discovery(endpoint: RestateEndpoint, discovered_as: typing.Literal["
                 description=description,
                 metadata=metadata,
                 inactivityTimeout=int(service.inactivity_timeout.total_seconds() * 1000)
-                if service.inactivity_timeout
+                if service.inactivity_timeout is not None
+                else None,
+                abortTimeout=int(service.abort_timeout.total_seconds() * 1000)
+                if service.abort_timeout is not None
                 else None,
-                abortTimeout=int(service.abort_timeout.total_seconds() * 1000) if service.abort_timeout else None,
                 journalRetention=int(service.journal_retention.total_seconds() * 1000)
-                if service.journal_retention
+                if service.journal_retention is not None
                 else None,
                 idempotencyRetention=int(service.idempotency_retention.total_seconds() * 1000)
-                if service.idempotency_retention
+                if service.idempotency_retention is not None
                 else None,
                 enableLazyState=service.enable_lazy_state if isinstance(service, (Workflow, VirtualObject)) else None,
                 ingressPrivate=service.ingress_private,
diff --git a/tests/discovery.py b/tests/discovery.py
new file mode 100644
index 0000000..8fe26fc
--- /dev/null
+++ b/tests/discovery.py
@@ -0,0 +1,57 @@
+#
+#  Copyright (c) 2023-2026 - Restate Software, Inc., Restate GmbH
+#
+#  This file is part of the Restate SDK for Python,
+#  which is released under the MIT license.
+#
+#  You can find a copy of the license in file LICENSE in the root
+#  directory of this repository or package, or at
+#  https://github.com/restatedev/sdk-typescript/blob/main/LICENSE
+#
+from datetime import timedelta
+
+import restate
+from restate.discovery import compute_discovery
+from restate.endpoint import Endpoint
+
+
+def test_zero_durations_are_preserved_in_manifest():
+    service = restate.Service(
+        "ZeroDurationService",
+        inactivity_timeout=timedelta(0),
+        abort_timeout=timedelta(0),
+        journal_retention=timedelta(0),
+        idempotency_retention=timedelta(0),
+    )
+
+    @service.handler(
+        inactivity_timeout=timedelta(0),
+        abort_timeout=timedelta(0),
+        journal_retention=timedelta(0),
+        idempotency_retention=timedelta(0),
+    )
+    async def handle(ctx: restate.Context):
+        pass
+
+    workflow = restate.Workflow("ZeroRetentionWorkflow")
+
+    @workflow.main(workflow_retention=timedelta(0))
+    async def run(ctx: restate.WorkflowContext):
+        pass
+
+    manifest = compute_discovery(Endpoint().bind(service, workflow), "bidi")
+
+    service_manifest = manifest.services[0]
+    assert service_manifest.inactivityTimeout == 0
+    assert service_manifest.abortTimeout == 0
+    assert service_manifest.journalRetention == 0
+    assert service_manifest.idempotencyRetention == 0
+
+    handler_manifest = service_manifest.handlers[0]
+    assert handler_manifest.inactivityTimeout == 0
+    assert handler_manifest.abortTimeout == 0
+    assert handler_manifest.journalRetention == 0
+    assert handler_manifest.idempotencyRetention == 0
+
+    workflow_handler_manifest = manifest.services[1].handlers[0]
+    assert workflow_handler_manifest.workflowCompletionRetention == 0