feat: expose generic draft steps over rpc

src/wf_transport_rpc_http/client/drafts.py

@@ -3,6 +3,9 @@ from __future__ import annotations
 from collections.abc import Sequence
 from typing import Any, Literal
 
+from wf_api.surface import RouteSource
+from wf_artifacts.drafts.models import DraftStep
+
 from .base import RpcCaller
 
 
@@ -207,6 +210,32 @@ class RpcDraftClientMixin:
             },
         )
 
+    async def add_step(
+        self: RpcCaller,
+        *,
+        workspace_id: str,
+        revision: int,
+        step_id: str,
+        step: DraftStep,
+        incoming: RouteSource | None = None,
+        routes: dict[str, str] | None = None,
+    ) -> dict[str, Any]:
+        return await self._call(
+            "workflow.draft_workspaces.add_step",
+            {
+                "workspace_id": workspace_id,
+                "revision": revision,
+                "step_id": step_id,
+                "step": step.model_dump(mode="json", by_alias=True),
+                "incoming": (
+                    None
+                    if incoming is None
+                    else {"step_id": incoming.step_id, "outcome": incoming.outcome}
+                ),
+                "routes": routes,
+            },
+        )
+
     async def branch_draft(
         self: RpcCaller,
         *,

src/wf_transport_rpc_http/methods/drafts.py

@@ -4,10 +4,12 @@ from typing import Any
 
 import fastapi_jsonrpc as jsonrpc
 
+from wf_api.surface import RouteSource
 from wf_server import WorkflowServer
 
 from ..errors import WorkflowRpcError, raise_workflow_rpc_error
 from ..models import (
+    AddDraftStepParams,
     AddStepFromCapabilityParams,
     BindDraftParams,
     BranchDraftParams,
@@ -243,6 +245,33 @@ def register_methods(
         except (ValueError, KeyError, LookupError, FileNotFoundError) as exc:
             raise_workflow_rpc_error(exc)
 
+    @entrypoint.method(
+        name="workflow.draft_workspaces.add_step",
+        errors=[WorkflowRpcError],
+    )
+    async def workflow_draft_workspaces_add_step(
+        params: AddDraftStepParams = RpcParams(),
+    ) -> dict[str, Any]:
+        try:
+            incoming = (
+                None
+                if params.incoming is None
+                else RouteSource(
+                    step_id=params.incoming.step_id,
+                    outcome=params.incoming.outcome,
+                )
+            )
+            return await server.api.add_step(
+                workspace_id=params.workspace_id,
+                revision=params.revision,
+                step_id=params.step_id,
+                step=params.step,
+                incoming=incoming,
+                routes=params.routes,
+            )
+        except (ValueError, KeyError, LookupError, FileNotFoundError) as exc:
+            raise_workflow_rpc_error(exc)
+
     @entrypoint.method(
         name="workflow.draft_workspaces.branch", errors=[WorkflowRpcError]
     )

src/wf_transport_rpc_http/models.py

@@ -5,6 +5,7 @@ from typing import Any, Literal
 from pydantic import BaseModel, ConfigDict, Field
 
 from wf_api.models import TraceRange
+from wf_artifacts.drafts.models import DraftStep
 
 
 class RpcParamsModel(BaseModel):
@@ -100,6 +101,20 @@ class ListDraftWorkspacesParams(RpcParamsModel):
     pass
 
 
+class RouteSourceParams(RpcParamsModel):
+    step_id: str = Field(min_length=1)
+    outcome: str = Field(default="ok", min_length=1)
+
+
+class AddDraftStepParams(RpcParamsModel):
+    workspace_id: str = Field(min_length=1)
+    revision: int = Field(ge=1)
+    step_id: str = Field(min_length=1)
+    step: DraftStep
+    incoming: RouteSourceParams | None = None
+    routes: dict[str, str] | None = None
+
+
 class GetDraftWorkspaceParams(RpcParamsModel):
     workspace_id: str = Field(min_length=1)
     include_draft: bool = False