feat: expose input bindings over rpc

src/wf_transport_rpc_http/__init__.py

@@ -43,6 +43,7 @@ from .models import (
     SetDraftNameParams,
     SetDraftRouteParams,
     SetDraftStartParams,
+    SetStepInputBindingsParams,
     SetStepInputMapParams,
     SetStepOutputMapParams,
     SetWorkflowOutputMapParams,
@@ -93,6 +94,7 @@ __all__ = [
     "SetDraftNameParams",
     "SetDraftRouteParams",
     "SetDraftStartParams",
+    "SetStepInputBindingsParams",
     "SetStepInputMapParams",
     "SetStepOutputMapParams",
     "SetWorkflowOutputMapParams",

src/wf_transport_rpc_http/client/drafts.py

@@ -5,6 +5,7 @@ from typing import Any, Literal
 
 from wf_api.surface import RouteSource
 from wf_artifacts.drafts.models import DraftStep
+from wf_core.models.steps import InputBinding
 
 from .base import RpcCaller
 
@@ -182,6 +183,24 @@ class RpcDraftClientMixin:
             },
         )
 
+    async def set_step_input_bindings(
+        self: RpcCaller,
+        *,
+        workspace_id: str,
+        revision: int,
+        step_id: str,
+        bindings: Sequence[InputBinding],
+    ) -> dict[str, Any]:
+        return await self._call(
+            "workflow.draft_workspaces.set_step_input_bindings",
+            {
+                "workspace_id": workspace_id,
+                "revision": revision,
+                "step_id": step_id,
+                "bindings": [binding.model_dump(mode="json") for binding in bindings],
+            },
+        )
+
     async def set_step_output_map(
         self: RpcCaller,
         *,

src/wf_transport_rpc_http/methods/drafts.py

@@ -31,6 +31,7 @@ from ..models import (
     SetDraftNameParams,
     SetDraftRouteParams,
     SetDraftStartParams,
+    SetStepInputBindingsParams,
     SetStepInputMapParams,
     SetStepOutputMapParams,
     SetWorkflowOutputMapParams,
@@ -226,6 +227,23 @@ def register_methods(
         except (ValueError, KeyError, LookupError, FileNotFoundError) as exc:
             raise_workflow_rpc_error(exc)
 
+    @entrypoint.method(
+        name="workflow.draft_workspaces.set_step_input_bindings",
+        errors=[WorkflowRpcError],
+    )
+    async def workflow_draft_workspaces_set_step_input_bindings(
+        params: SetStepInputBindingsParams = RpcParams(),
+    ) -> dict[str, Any]:
+        try:
+            return await server.api.set_step_input_bindings(
+                workspace_id=params.workspace_id,
+                revision=params.revision,
+                step_id=params.step_id,
+                bindings=params.bindings,
+            )
+        except (ValueError, KeyError, LookupError, FileNotFoundError) as exc:
+            raise_workflow_rpc_error(exc)
+
     @entrypoint.method(
         name="workflow.draft_workspaces.set_step_output_map",
         errors=[WorkflowRpcError],

src/wf_transport_rpc_http/models.py

@@ -6,6 +6,7 @@ from pydantic import BaseModel, ConfigDict, Field, model_validator
 
 from wf_api.models import TraceRange
 from wf_artifacts.drafts.models import DraftStep
+from wf_core.models.steps import InputBinding
 
 
 class RpcParamsModel(BaseModel):
@@ -208,6 +209,13 @@ class SetStepInputMapParams(RpcParamsModel):
     merge: bool = False
 
 
+class SetStepInputBindingsParams(RpcParamsModel):
+    workspace_id: str = Field(min_length=1)
+    revision: int = Field(ge=1)
+    step_id: str = Field(min_length=1)
+    bindings: list[InputBinding]
+
+
 class SetStepOutputMapParams(RpcParamsModel):
     workspace_id: str = Field(min_length=1)
     revision: int = Field(ge=1)

tests/wf_transport_rpc_http/test_app.py

@@ -890,6 +890,75 @@ async def test_rpc_draft_workspace_focused_edit_methods(tmp_path) -> None:
     )
 
 
+async def test_rpc_set_step_input_bindings_preserves_canonical_order(tmp_path) -> None:
+    server = build_local_static_workflow_server(tmp_path / "store")
+    app = create_rpc_app(server)
+    transport = httpx.ASGITransport(app=app)
+    async with httpx.AsyncClient(transport=transport, base_url="http://test") as client:
+        await _rpc(
+            client,
+            "workflow.draft_workspaces.create_from_capability",
+            {
+                "workspace_id": "binding_ws",
+                "capability_name": "wf.std.concat",
+                "name": "binding_transport",
+            },
+        )
+        result = await _rpc(
+            client,
+            "workflow.draft_workspaces.set_step_input_bindings",
+            {
+                "workspace_id": "binding_ws",
+                "revision": 1,
+                "step_id": "call",
+                "bindings": [
+                    {"path": "input.items", "target": "items"},
+                    {"value": "\n", "target": "separator"},
+                ],
+            },
+        )
+        inspected = await _rpc(
+            client,
+            "workflow.draft_workspaces.get",
+            {"workspace_id": "binding_ws", "include_draft": True},
+        )
+
+    assert result["result"]["revision"] == 2
+    assert inspected["result"]["draft"]["steps"]["call"]["input"] == [
+        {"target": "items", "path": "input.items"},
+        {"target": "separator", "value": "\n"},
+    ]
+
+
+@pytest.mark.parametrize(
+    "binding",
+    [
+        {"path": "input.items", "value": [], "target": "items"},
+        {"target": "items"},
+    ],
+)
+async def test_rpc_set_step_input_bindings_rejects_malformed_union(
+    tmp_path,
+    binding: dict[str, Any],
+) -> None:
+    server = build_local_static_workflow_server(tmp_path / "store")
+    app = create_rpc_app(server)
+    transport = httpx.ASGITransport(app=app)
+    async with httpx.AsyncClient(transport=transport, base_url="http://test") as client:
+        rejected = await _rpc(
+            client,
+            "workflow.draft_workspaces.set_step_input_bindings",
+            {
+                "workspace_id": "missing_ws",
+                "revision": 1,
+                "step_id": "call",
+                "bindings": [binding],
+            },
+        )
+
+    assert rejected["error"]["code"] == -32602
+
+
 async def test_rpc_draft_workspace_set_workflow_output_map(tmp_path) -> None:
     server = build_local_static_workflow_server(tmp_path / "store")
     app = create_rpc_app(server)

tests/wf_transport_rpc_http/test_client.py

@@ -15,6 +15,7 @@ from wf_artifacts.drafts.models import (
     DraftStep,
 )
 from wf_core import END
+from wf_core.models.steps import InputPathBinding, InputValueBinding
 from wf_server import build_local_static_workflow_server
 from wf_transport_rpc_http import RpcWorkflowApiClient, create_rpc_app
 from wf_transport_rpc_http.client.drafts import RpcDraftClientMixin
@@ -689,6 +690,40 @@ async def test_rpc_client_draft_workspace_focused_edit_methods(tmp_path) -> None
     assert state_bound["revision"] == 8
 
 
+async def test_rpc_client_serializes_canonical_step_input_bindings() -> None:
+    calls: list[tuple[str, dict[str, object]]] = []
+
+    class Client(RpcDraftClientMixin):
+        async def _call(self, method: str, params: dict[str, object]):
+            calls.append((method, params))
+            return {"revision": 3}
+
+    client = Client()
+
+    await client.set_step_input_bindings(
+        workspace_id="client_ws",
+        revision=2,
+        step_id="call",
+        bindings=[
+            InputPathBinding(path="state.title", target="request.title"),
+            InputValueBinding(target="request.format", value="markdown"),
+        ],
+    )
+
+    assert calls[-1] == (
+        "workflow.draft_workspaces.set_step_input_bindings",
+        {
+            "workspace_id": "client_ws",
+            "revision": 2,
+            "step_id": "call",
+            "bindings": [
+                {"target": "request.title", "path": "state.title"},
+                {"target": "request.format", "value": "markdown"},
+            ],
+        },
+    )
+
+
 async def test_rpc_client_draft_remove_methods(tmp_path) -> None:
     calls: list[dict[str, Any]] = []