diff --git a/contracts/workflow-api.manifest.json b/contracts/workflow-api.manifest.json
index fff50a0a..1a5ea5ec 100644
--- a/contracts/workflow-api.manifest.json
+++ b/contracts/workflow-api.manifest.json
@@ -9065,6 +9065,10 @@
           "required": false,
           "schema": {
             "default": "skip",
+            "enum": [
+              "skip",
+              "parallel"
+            ],
             "type": "string"
           }
         },
@@ -9073,6 +9077,10 @@
           "required": false,
           "schema": {
             "default": "skip",
+            "enum": [
+              "skip",
+              "latest"
+            ],
             "type": "string"
           }
         },
@@ -9404,6 +9412,10 @@
           "schema": {
             "anyOf": [
               {
+                "enum": [
+                  "skip",
+                  "parallel"
+                ],
                 "type": "string"
               },
               {
@@ -9419,6 +9431,10 @@
           "schema": {
             "anyOf": [
               {
+                "enum": [
+                  "skip",
+                  "latest"
+                ],
                 "type": "string"
               },
               {
@@ -9434,6 +9450,7 @@
           "schema": {
             "anyOf": [
               {
+                "minimum": 1,
                 "type": "integer"
               },
               {
@@ -9449,6 +9466,7 @@
           "schema": {
             "anyOf": [
               {
+                "minimum": 0,
                 "type": "number"
               },
               {
@@ -9464,6 +9482,7 @@
           "schema": {
             "anyOf": [
               {
+                "minimum": 1,
                 "type": "integer"
               },
               {
diff --git a/src/wf_api/surface.py b/src/wf_api/surface.py
index 708783f5..72e4dc65 100644
--- a/src/wf_api/surface.py
+++ b/src/wf_api/surface.py
@@ -6,6 +6,7 @@ from typing import Any, Literal, Protocol, overload
 from wf_artifacts import ArtifactKind
 from wf_artifacts.drafts.models import DraftStep
 from wf_core.models.steps import InputBinding, OutputBinding, StepInputBinding
+from wf_scheduling.models import MisfirePolicy, OverlapPolicy
 
 from .draft_authoring import RouteSource
 from .draft_updates import CapabilityStepUpdate
@@ -561,8 +562,8 @@ class WorkflowScheduleSurface(Protocol):
         deployment_id: str,
         trigger: dict[str, Any],
         input_bindings: list[dict[str, Any]] | None = None,
-        overlap: str = "skip",
-        misfire: str = "skip",
+        overlap: OverlapPolicy = "skip",
+        misfire: MisfirePolicy = "skip",
         max_active_runs: int = 1,
         lateness_allowance_s: float = 60.0,
         max_steps: int | None = None,
@@ -589,8 +590,8 @@ class WorkflowScheduleSurface(Protocol):
         deployment_id: str | None = None,
         trigger: dict[str, Any] | None = None,
         input_bindings: list[dict[str, Any]] | None = None,
-        overlap: str | None = None,
-        misfire: str | None = None,
+        overlap: OverlapPolicy | None = None,
+        misfire: MisfirePolicy | None = None,
         max_active_runs: int | None = None,
         lateness_allowance_s: float | None = None,
         max_steps: int | None = None,
diff --git a/src/wf_transport_rpc_http/models.py b/src/wf_transport_rpc_http/models.py
index 4d9f45cd..525aa98d 100644
--- a/src/wf_transport_rpc_http/models.py
+++ b/src/wf_transport_rpc_http/models.py
@@ -8,6 +8,7 @@ from wf_api import CapabilityStepUpdate
 from wf_api.models import TraceRange
 from wf_artifacts.drafts.models import DraftStep
 from wf_core.models.steps import InputBinding, OutputBinding, StepInputBinding
+from wf_scheduling.models import MisfirePolicy, OverlapPolicy
 
 
 class RpcParamsModel(BaseModel):
@@ -467,8 +468,8 @@ class CreateScheduleParams(RpcParamsModel):
     deployment_id: str = Field(min_length=1)
     trigger: dict[str, Any]
     input_bindings: list[dict[str, Any]] = Field(default_factory=list)
-    overlap: str = "skip"
-    misfire: str = "skip"
+    overlap: OverlapPolicy = "skip"
+    misfire: MisfirePolicy = "skip"
     max_active_runs: int = Field(default=1, ge=1)
     lateness_allowance_s: float = Field(default=60.0, ge=0)
     max_steps: int | None = Field(
@@ -496,8 +497,8 @@ class UpdateScheduleParams(RpcParamsModel):
     deployment_id: str | None = None
     trigger: dict[str, Any] | None = None
     input_bindings: list[dict[str, Any]] | None = None
-    overlap: str | None = None
-    misfire: str | None = None
+    overlap: OverlapPolicy | None = None
+    misfire: MisfirePolicy | None = None
     max_active_runs: int | None = Field(default=None, ge=1)
     lateness_allowance_s: float | None = Field(default=None, ge=0)
     max_steps: int | None = Field(default=None, ge=1, strict=True)
diff --git a/tests/wf_transport_rpc_http/test_rpc_models.py b/tests/wf_transport_rpc_http/test_rpc_models.py
index 610563b7..2fd8909d 100644
--- a/tests/wf_transport_rpc_http/test_rpc_models.py
+++ b/tests/wf_transport_rpc_http/test_rpc_models.py
@@ -5,6 +5,7 @@ from pydantic import ValidationError
 
 from wf_core.models.steps import InputExpressionBinding
 from wf_transport_rpc_http.models import (
+    CreateScheduleParams,
     InspectCapabilityParams,
     ListCapabilitiesParams,
     ReadRunTraceParams,
@@ -94,6 +95,20 @@ def test_update_schedule_params_match_create_numeric_constraints() -> None:
         )
 
 
+def test_schedule_policy_params_reject_unknown_values() -> None:
+    with pytest.raises(ValidationError):
+        CreateScheduleParams(
+            schedule_id="schedule",
+            deployment_id="deployment",
+            trigger={"kind": "oneshot", "at": "2026-09-08T12:00:00+00:00"},
+            overlap="queue",
+        )
+    with pytest.raises(ValidationError):
+        UpdateScheduleParams(
+            schedule_id="schedule", expected_revision=1, misfire="replay"
+        )
+
+
 def test_step_input_params_accept_composite_bindings_but_workflow_output_does_not() -> (
     None
 ):