feat: merge draft step maps

docs/current_roadmap.md

@@ -57,6 +57,9 @@ clear operator feedback before adding more architecture.
 - Completed: focused draft edit helpers are exposed through RPC/CLI, and
   `wf deploy create` is accepted as an alias for `wf deploy save`. Docs now
   distinguish draft shape from raw plan shape for agent authoring.
+- Completed: `wf draft set-input` and `wf draft set-output` now accept
+  `--merge`, preserving existing bindings when agents split map edits across
+  multiple revisions.
 - Completed: `wf schema` now lists workflow document/component models, emits
   compact JSON outlines for agent discovery, and emits valid self-contained
   JSON Schema with `--verbose`.

docs/wf_cli.md

@@ -296,6 +296,7 @@ wf draft set-name concat_ws --revision 1 --name concat_ws_v2
 wf draft set-route concat_ws --revision 2 --step call --outcome ok --to __end__
 wf draft set-input concat_ws --revision 3 --step call --map input.items=items --map input.separator=separator
 wf draft set-output concat_ws --revision 4 --step call --map value=state.value
+wf draft set-input concat_ws --revision 5 --step call --merge --map input.limit=limit
 ```
 
 `set-input` maps graph source paths to node-local input fields:
@@ -304,6 +305,11 @@ wf draft set-output concat_ws --revision 4 --step call --map value=state.value
 `set-output` maps node-local output fields to workflow state paths:
 `text=state.text` means `local.text -> state.text`.
 
+By default, `set-input` and `set-output` replace the whole map for that step.
+Use repeated `--map` flags in one command when you know the complete map. Use
+`--merge` when adding or updating one entry across a later revision while
+preserving existing bindings.
+
 Validate:
 
 ```bash

skills/wf-cli/SKILL.md

@@ -41,7 +41,9 @@ wf draft patch <workspace_id> --revision <n> --input-file patch.json
 wf draft set-name <workspace_id> --revision <n> --name <name>
 wf draft set-route <workspace_id> --revision <n> --step <step_id> --outcome <outcome> --to <target>
 wf draft set-input <workspace_id> --revision <n> --step <step_id> --map input.text=text
+wf draft set-input <workspace_id> --revision <n> --step <step_id> --merge --map input.other=other
 wf draft set-output <workspace_id> --revision <n> --step <step_id> --map text=state.text
+wf draft set-output <workspace_id> --revision <n> --step <step_id> --merge --map other=state.other
 wf draft validate <workspace_id>
 wf draft save <workspace_id> --artifact <artifact_id> --version <n> --title <title>
 
@@ -67,6 +69,10 @@ Use public CLI surfaces before broader documentation or implementation search:
 Use `wf schema <name> --verbose` only when the complete JSON Schema is required;
 the default compact outline is preferred for agent context.
 
+For `draft set-input` and `draft set-output`, repeated `--map` flags in one
+command define the complete replacement map. If you split map edits across
+multiple commands, pass `--merge` or the later command replaces the earlier map.
+
 ## Rules
 
 - Use explicit `--config <path>` for examples, challenge workspaces, and

skills/wf-workflow/references/draft-workspaces.md

@@ -80,7 +80,9 @@ CLI equivalents:
 wf draft set-name <workspace_id> --revision <n> --name <name>
 wf draft set-route <workspace_id> --revision <n> --step <step_id> --outcome ok --to <target>
 wf draft set-input <workspace_id> --revision <n> --step <step_id> --map input.text=text
+wf draft set-input <workspace_id> --revision <n> --step <step_id> --merge --map input.other=other
 wf draft set-output <workspace_id> --revision <n> --step <step_id> --map text=state.text
+wf draft set-output <workspace_id> --revision <n> --step <step_id> --merge --map other=state.other
 ```
 
 `set-input` direction: `input.text=text` means graph source `input.text` maps to
@@ -89,6 +91,10 @@ node-local target `local.text`.
 `set-output` direction: `text=state.text` means node-local source `local.text`
 maps to graph target `state.text`.
 
+Without `--merge`, `set-input` and `set-output` replace the whole map for that
+step. Use repeated `--map` flags in one command for a complete replacement. Use
+`--merge` only when adding/updating entries over multiple revisions.
+
 Use JSON Patch for structural edits the helpers do not cover.
 
 For larger patches, write a JSON Patch array to a file and pass it with

skills/wf-workflow/references/workflow-lifecycle.md

@@ -16,6 +16,8 @@ validated, runnable deployment.
 5. Inspect/patch/validate the workspace until valid.
    - Use focused CLI commands (`set-name`, `set-route`, `set-input`, `set-output`)
      for common edits.
+   - `set-input` and `set-output` replace full maps by default; pass `--merge`
+     only when adding or updating one entry across a later revision.
    - Use JSON Patch only for general structural edits.
 6. Save an artifact.
    - Draft artifact:

src/wf_api/drafts.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from collections.abc import Sequence
+from collections.abc import Mapping, Sequence
 from typing import Any
 
 from wf_artifacts import (
@@ -207,7 +207,15 @@ class WorkflowDraftApi:
         revision: int,
         step_id: str,
         input_map: dict[str, str],
+        merge: bool = False,
     ) -> dict[str, Any]:
+        input_values: dict[str, Any] = {}
+        if merge:
+            existing_map, input_values = self._step_input_maps(
+                workspace_id=workspace_id,
+                step_id=step_id,
+            )
+            input_map = {**existing_map, **input_map}
         return await self.patch_draft_workspace(
             workspace_id=workspace_id,
             revision=revision,
@@ -215,7 +223,7 @@ class WorkflowDraftApi:
                 {
                     "op": "replace",
                     "path": f"/steps/{_escape_json_pointer(step_id)}/input",
-                    "value": _draft_input_bindings_payload(input_map, {}),
+                    "value": _draft_input_bindings_payload(input_map, input_values),
                 }
             ],
         )
@@ -227,7 +235,13 @@ class WorkflowDraftApi:
         revision: int,
         step_id: str,
         output_map: dict[str, str],
+        merge: bool = False,
     ) -> dict[str, Any]:
+        if merge:
+            output_map = {
+                **self._step_output_map(workspace_id=workspace_id, step_id=step_id),
+                **output_map,
+            }
         return await self.patch_draft_workspace(
             workspace_id=workspace_id,
             revision=revision,
@@ -240,6 +254,21 @@ class WorkflowDraftApi:
             ],
         )
 
+    def _step_input_maps(
+        self,
+        *,
+        workspace_id: str,
+        step_id: str,
+    ) -> tuple[dict[str, str], dict[str, Any]]:
+        workspace = self._draft_store().get_workspace(workspace_id)
+        step = _draft_step(workspace.draft, step_id)
+        return _input_maps_from_payload(step.get("input", []))
+
+    def _step_output_map(self, *, workspace_id: str, step_id: str) -> dict[str, str]:
+        workspace = self._draft_store().get_workspace(workspace_id)
+        step = _draft_step(workspace.draft, step_id)
+        return _output_map_from_payload(step.get("output", []))
+
     async def create_minimal_draft_workspace(
         self,
         *,
@@ -374,6 +403,72 @@ def _draft_output_bindings_payload(output_map: dict[str, str]) -> list[dict[str,
     ]
 
 
+def _draft_step(draft: Mapping[str, Any], step_id: str) -> Mapping[str, Any]:
+    steps = draft.get("steps", {})
+    if not isinstance(steps, Mapping):
+        raise KeyError("draft steps are not available")
+    step = steps[step_id]
+    if not isinstance(step, Mapping):
+        raise KeyError(f"draft step {step_id!r} is not an object")
+    return step
+
+
+def _input_maps_from_payload(
+    payload: Any,
+) -> tuple[dict[str, str], dict[str, Any]]:
+    """Read stored canonical input bindings back into focused draft maps."""
+    input_map: dict[str, str] = {}
+    input_values: dict[str, Any] = {}
+    if not isinstance(payload, list):
+        return input_map, input_values
+    for item in payload:
+        if not isinstance(item, Mapping) or "target" not in item:
+            continue
+        target = _path_text(item["target"], expected_root="local")
+        if "path" in item:
+            input_map[_path_text(item["path"])] = target
+        elif "value" in item:
+            input_values[target] = item["value"]
+    return input_map, input_values
+
+
+def _output_map_from_payload(payload: Any) -> dict[str, str]:
+    """Read stored canonical output bindings back into the focused output map."""
+    output_map: dict[str, str] = {}
+    if not isinstance(payload, list):
+        return output_map
+    for item in payload:
+        if not isinstance(item, Mapping):
+            continue
+        if "source" in item and "target" in item:
+            output_map[_path_text(item["source"], expected_root="local")] = _path_text(
+                item["target"],
+                expected_root="state",
+            )
+    return output_map
+
+
+def _path_text(value: Any, *, expected_root: str | None = None) -> str:
+    """Return compact dotted text for stored structural path JSON."""
+    if isinstance(value, str):
+        return value
+    if not isinstance(value, Mapping):
+        raise ValueError(f"expected path object, got {value!r}")
+    root = value.get("root")
+    if expected_root is not None and root != expected_root:
+        raise ValueError(f"expected {expected_root} path root")
+    if not isinstance(root, str):
+        raise ValueError("path root must be a string")
+    raw_parts = value.get("parts", [])
+    if not isinstance(raw_parts, list) or not all(
+        isinstance(part, str) for part in raw_parts
+    ):
+        raise ValueError("path parts must be strings")
+    if root == "local":
+        return "." if not raw_parts else ".".join(raw_parts)
+    return root if not raw_parts else f"{root}.{'.'.join(raw_parts)}"
+
+
 def _graph_path_payload(value: str | GraphSourcePath) -> dict[str, str | list[str]]:
     path = value if isinstance(value, GraphSourcePath) else GraphSourcePath.parse(value)
     return GraphSourcePath._serialize(path)

src/wf_api/service.py

@@ -335,12 +335,14 @@ class WorkflowApi:
         revision: int,
         step_id: str,
         input_map: dict[str, str],
+        merge: bool = False,
     ) -> dict[str, Any]:
         return await self.drafts.set_step_input_map(
             workspace_id=workspace_id,
             revision=revision,
             step_id=step_id,
             input_map=input_map,
+            merge=merge,
         )
 
     async def set_step_output_map(
@@ -350,12 +352,14 @@ class WorkflowApi:
         revision: int,
         step_id: str,
         output_map: dict[str, str],
+        merge: bool = False,
     ) -> dict[str, Any]:
         return await self.drafts.set_step_output_map(
             workspace_id=workspace_id,
             revision=revision,
             step_id=step_id,
             output_map=output_map,
+            merge=merge,
         )
 
     async def create_minimal_draft_workspace(

src/wf_api/surface.py

@@ -101,6 +101,7 @@ class WorkflowDraftSurface(Protocol):
         revision: int,
         step_id: str,
         input_map: dict[str, str],
+        merge: bool = False,
     ) -> dict[str, Any]: ...
 
     async def set_step_output_map(
@@ -110,6 +111,7 @@ class WorkflowDraftSurface(Protocol):
         revision: int,
         step_id: str,
         output_map: dict[str, str],
+        merge: bool = False,
     ) -> dict[str, Any]: ...
 
     async def validate_draft_workspace(

src/wf_cli/commands/drafts.py

@@ -193,11 +193,26 @@ def set_step_input_map(
         list[str] | None,
         typer.Option(
             "--map",
-            help="Input binding SOURCE=LOCAL_TARGET. Repeatable. Example: input.text=text",
+            help="One input binding SOURCE=LOCAL_TARGET. Repeat in one command.",
         ),
     ] = None,
+    merge: Annotated[
+        bool,
+        typer.Option(
+            "--merge",
+            help="Preserve existing input bindings and add/update the passed --map entries.",
+        ),
+    ] = False,
 ) -> None:
-    """Replace one step's input map without writing JSON Patch manually."""
+    """Set one step's input map without writing JSON Patch manually.
+
+    Default behavior replaces the full input map for this step. Pass all desired
+    --map entries in one command for a complete replacement. Use --merge only
+    when adding or updating entries across a later revision.
+
+    Run `wf draft validate <workspace_id>` after map edits; validation reports
+    unresolved paths and conflicting writes.
+    """
     input_map = _parse_map_flags(mapping)
     context = load_cli_context(ctx)
     emit_json(
@@ -208,6 +223,7 @@ def set_step_input_map(
                 revision=revision,
                 step_id=step_id,
                 input_map=input_map,
+                merge=merge,
             ),
         )
     )
@@ -225,11 +241,26 @@ def set_step_output_map(
         list[str] | None,
         typer.Option(
             "--map",
-            help="Output binding LOCAL_SOURCE=STATE_TARGET. Repeatable. Example: text=state.text",
+            help="One output binding LOCAL_SOURCE=STATE_TARGET. Repeat in one command.",
         ),
     ] = None,
+    merge: Annotated[
+        bool,
+        typer.Option(
+            "--merge",
+            help="Preserve existing output bindings and add/update the passed --map entries.",
+        ),
+    ] = False,
 ) -> None:
-    """Replace one step's output map without writing JSON Patch manually."""
+    """Set one step's output map without writing JSON Patch manually.
+
+    Default behavior replaces the full output map for this step. Pass all
+    desired --map entries in one command for a complete replacement. Use
+    --merge only when adding or updating entries across a later revision.
+
+    Run `wf draft validate <workspace_id>` after map edits; validation reports
+    unresolved paths and conflicting writes.
+    """
     output_map = _parse_map_flags(mapping)
     context = load_cli_context(ctx)
     emit_json(
@@ -240,6 +271,7 @@ def set_step_output_map(
                 revision=revision,
                 step_id=step_id,
                 output_map=output_map,
+                merge=merge,
             ),
         )
     )

src/wf_mcp/workflow_surface/models.py

@@ -206,21 +206,35 @@ class SetDraftRouteRequest(BaseModel):
 
 
 class SetStepInputMapRequest(BaseModel):
-    """Typed MCP request for replacing one step input map."""
+    """Typed MCP request for replacing or merging one step input map."""
 
     workspace_id: WorkspaceId
     revision: int = Field(ge=1, description="Expected current workspace revision.")
     step_id: str = Field(description="Draft step id whose input map should change.")
     input_map: DraftPathMap
+    merge: bool = Field(
+        default=False,
+        description=(
+            "When false, replace the full input map. When true, preserve existing "
+            "bindings and add/update only input_map entries."
+        ),
+    )
 
 
 class SetStepOutputMapRequest(BaseModel):
-    """Typed MCP request for replacing one step output map."""
+    """Typed MCP request for replacing or merging one step output map."""
 
     workspace_id: WorkspaceId
     revision: int = Field(ge=1, description="Expected current workspace revision.")
     step_id: str = Field(description="Draft step id whose output map should change.")
     output_map: DraftPathMap
+    merge: bool = Field(
+        default=False,
+        description=(
+            "When false, replace the full output map. When true, preserve existing "
+            "bindings and add/update only output_map entries."
+        ),
+    )
 
 
 class DeleteDraftWorkspaceRequest(BaseModel):

src/wf_mcp/workflow_surface/tools.py

@@ -399,7 +399,8 @@ def register_workflow_tools(server: FastMCP[Any], service: WfMcpService) -> None
         name="wf.workflow.set_step_input_map",
         title="Set Step Input Map",
         description=(
-            "Replace one compatibility step input map in a draft workspace. "
+            "Replace or merge one compatibility step input map in a draft workspace. "
+            "Set merge=true to preserve existing bindings while adding/updating entries. "
             "New one-capability bootstraps should prefer canonical input bindings."
         ),
     )
@@ -412,6 +413,7 @@ def register_workflow_tools(server: FastMCP[Any], service: WfMcpService) -> None
                 revision=request.revision,
                 step_id=request.step_id,
                 input_map=request.input_map,
+                merge=request.merge,
             )
         )
 
@@ -419,7 +421,8 @@ def register_workflow_tools(server: FastMCP[Any], service: WfMcpService) -> None
         name="wf.workflow.set_step_output_map",
         title="Set Step Output Map",
         description=(
-            "Replace one compatibility step output map in a draft workspace. "
+            "Replace or merge one compatibility step output map in a draft workspace. "
+            "Set merge=true to preserve existing bindings while adding/updating entries. "
             "New one-capability bootstraps should prefer canonical output bindings."
         ),
     )
@@ -432,6 +435,7 @@ def register_workflow_tools(server: FastMCP[Any], service: WfMcpService) -> None
                 revision=request.revision,
                 step_id=request.step_id,
                 output_map=request.output_map,
+                merge=request.merge,
             )
         )
 

src/wf_transport_rpc_http/client/drafts.py

@@ -108,6 +108,7 @@ class RpcDraftClientMixin:
         revision: int,
         step_id: str,
         input_map: dict[str, str],
+        merge: bool = False,
     ) -> dict[str, Any]:
         return await self._call(
             "workflow.draft_workspaces.set_step_input_map",
@@ -116,6 +117,7 @@ class RpcDraftClientMixin:
                 "revision": revision,
                 "step_id": step_id,
                 "input_map": input_map,
+                "merge": merge,
             },
         )
 
@@ -126,6 +128,7 @@ class RpcDraftClientMixin:
         revision: int,
         step_id: str,
         output_map: dict[str, str],
+        merge: bool = False,
     ) -> dict[str, Any]:
         return await self._call(
             "workflow.draft_workspaces.set_step_output_map",
@@ -134,6 +137,7 @@ class RpcDraftClientMixin:
                 "revision": revision,
                 "step_id": step_id,
                 "output_map": output_map,
+                "merge": merge,
             },
         )
 

src/wf_transport_rpc_http/methods/drafts.py

@@ -154,6 +154,7 @@ def register_methods(
                 revision=params.revision,
                 step_id=params.step_id,
                 input_map=params.input_map,
+                merge=params.merge,
             )
         except (ValueError, KeyError, LookupError, FileNotFoundError) as exc:
             raise_workflow_rpc_error(exc)
@@ -171,6 +172,7 @@ def register_methods(
                 revision=params.revision,
                 step_id=params.step_id,
                 output_map=params.output_map,
+                merge=params.merge,
             )
         except (ValueError, KeyError, LookupError, FileNotFoundError) as exc:
             raise_workflow_rpc_error(exc)

src/wf_transport_rpc_http/models.py

@@ -130,6 +130,7 @@ class SetStepInputMapParams(RpcParamsModel):
     revision: int = Field(ge=1)
     step_id: str = Field(min_length=1)
     input_map: dict[str, str]
+    merge: bool = False
 
 
 class SetStepOutputMapParams(RpcParamsModel):
@@ -137,6 +138,7 @@ class SetStepOutputMapParams(RpcParamsModel):
     revision: int = Field(ge=1)
     step_id: str = Field(min_length=1)
     output_map: dict[str, str]
+    merge: bool = False
 
 
 class ValidateDraftWorkspaceParams(RpcParamsModel):

tests/wf_api/test_drafts_service.py

@@ -241,6 +241,58 @@ async def test_draft_workspace_patch_helpers_update_revision_and_bindings(
     ]
 
 
+@pytest.mark.asyncio
+async def test_step_map_helpers_merge_with_existing_bindings(tmp_path: Path) -> None:
+    artifact_store = FileWorkflowArtifactStore(tmp_path / "drafts_patch_helper_merge")
+    api, _service = _draft_api(artifact_store)
+    await api.create_draft_workspace(
+        workspace_id="echo_ws",
+        draft=_echo_draft(),
+    )
+
+    input_mapped = await api.set_step_input_map(
+        workspace_id="echo_ws",
+        revision=1,
+        step_id="echo",
+        input_map={"input.extra": "extra"},
+        merge=True,
+    )
+    output_mapped = await api.set_step_output_map(
+        workspace_id="echo_ws",
+        revision=2,
+        step_id="echo",
+        output_map={"extra": "state.extra"},
+        merge=True,
+    )
+    replaced = await api.set_step_input_map(
+        workspace_id="echo_ws",
+        revision=3,
+        step_id="echo",
+        input_map={"input.final": "final"},
+    )
+    fetched = await api.get_draft_workspace(workspace_id="echo_ws", include_draft=True)
+
+    assert input_mapped["revision"] == 2
+    assert output_mapped["revision"] == 3
+    assert replaced["revision"] == 4
+    assert fetched["draft"]["steps"]["echo"]["input"] == [
+        {
+            "target": {"root": "local", "parts": ["final"]},
+            "path": {"root": "input", "parts": ["final"]},
+        }
+    ]
+    assert fetched["draft"]["steps"]["echo"]["output"] == [
+        {
+            "source": {"root": "local", "parts": ["echoed"]},
+            "target": {"root": "state", "parts": ["echoed"]},
+        },
+        {
+            "source": {"root": "local", "parts": ["extra"]},
+            "target": {"root": "state", "parts": ["extra"]},
+        },
+    ]
+
+
 @pytest.mark.asyncio
 async def test_validate_draft_workspace_refreshes_status(tmp_path: Path) -> None:
     artifact_store = FileWorkflowArtifactStore(tmp_path / "drafts_validate_workspace")

tests/wf_cli/test_app.py

@@ -126,3 +126,19 @@ def test_wf_draft_create_from_capability_help_exists() -> None:
 
     assert result.exit_code == 0
     assert "--title" in result.output
+
+
+def test_wf_draft_map_help_explains_replace_merge_and_validate() -> None:
+    input_result = runner.invoke(app, ["draft", "set-input", "--help"])
+    output_result = runner.invoke(app, ["draft", "set-output", "--help"])
+
+    assert input_result.exit_code == 0
+    assert output_result.exit_code == 0
+    input_help = " ".join(input_result.output.split())
+    output_help = " ".join(output_result.output.split())
+    assert "replaces the full input map" in input_help
+    assert "Use --merge only" in input_help
+    assert "draft validate" in input_help
+    assert "replaces the full output map" in output_help
+    assert "Use --merge only" in output_help
+    assert "draft validate" in output_help

tests/wf_cli/test_remote_target.py

@@ -1027,6 +1027,38 @@ def test_wf_draft_focused_edit_commands_use_rpc_target(monkeypatch, tmp_path) ->
             "value=state.value",
         ],
     )
+    input_merged = runner.invoke(
+        app,
+        [
+            *base_args,
+            "draft",
+            "set-input",
+            "focused_ws",
+            "--revision",
+            "5",
+            "--step",
+            "call",
+            "--map",
+            "input.extra=extra",
+            "--merge",
+        ],
+    )
+    output_merged = runner.invoke(
+        app,
+        [
+            *base_args,
+            "draft",
+            "set-output",
+            "focused_ws",
+            "--revision",
+            "6",
+            "--step",
+            "call",
+            "--map",
+            "extra=state.extra",
+            "--merge",
+        ],
+    )
     inspected = runner.invoke(
         app,
         [*base_args, "draft", "inspect", "focused_ws", "--include-draft"],
@@ -1036,6 +1068,8 @@ def test_wf_draft_focused_edit_commands_use_rpc_target(monkeypatch, tmp_path) ->
     assert routed.exit_code == 0, routed.output
     assert input_mapped.exit_code == 0, input_mapped.output
     assert output_mapped.exit_code == 0, output_mapped.output
+    assert input_merged.exit_code == 0, input_merged.output
+    assert output_merged.exit_code == 0, output_merged.output
     assert inspected.exit_code == 0, inspected.output
     payload = json.loads(inspected.output)
     draft = payload["draft"]
@@ -1045,13 +1079,21 @@ def test_wf_draft_focused_edit_commands_use_rpc_target(monkeypatch, tmp_path) ->
         {
             "target": {"root": "local", "parts": ["value"]},
             "path": {"root": "input", "parts": ["value"]},
-        }
+        },
+        {
+            "target": {"root": "local", "parts": ["extra"]},
+            "path": {"root": "input", "parts": ["extra"]},
+        },
     ]
     assert draft["steps"]["call"]["output"] == [
         {
             "source": {"root": "local", "parts": ["value"]},
             "target": {"root": "state", "parts": ["value"]},
-        }
+        },
+        {
+            "source": {"root": "local", "parts": ["extra"]},
+            "target": {"root": "state", "parts": ["extra"]},
+        },
     ]
 
 

tests/wf_mcp/server/test_config.py

@@ -107,6 +107,11 @@ def test_server_exposes_upstream_admin_and_workflow_tools() -> None:
             assert "input" in from_capability_request["properties"]
             assert "output" in from_capability_request["properties"]
             assert "output_map" in from_capability_request["properties"]
+            set_input_schema = tools_by_name[
+                "wf.workflow.set_step_input_map"
+            ].inputSchema
+            set_input_request = set_input_schema["properties"]["request"]
+            assert "merge" in set_input_request["properties"]
             from_capability_output = tools_by_name[
                 "wf.workflow.create_draft_workspace_from_capability"
             ].outputSchema

tests/wf_transport_rpc_http/test_app.py

@@ -700,6 +700,28 @@ async def test_rpc_draft_workspace_focused_edit_methods(tmp_path) -> None:
                 "output_map": {"value": "state.value"},
             },
         )
+        input_merged = await _rpc(
+            client,
+            "workflow.draft_workspaces.set_step_input_map",
+            {
+                "workspace_id": "focused_ws",
+                "revision": 5,
+                "step_id": "call",
+                "input_map": {"input.extra": "extra"},
+                "merge": True,
+            },
+        )
+        output_merged = await _rpc(
+            client,
+            "workflow.draft_workspaces.set_step_output_map",
+            {
+                "workspace_id": "focused_ws",
+                "revision": 6,
+                "step_id": "call",
+                "output_map": {"extra": "state.extra"},
+                "merge": True,
+            },
+        )
         fetched = await _rpc(
             client,
             "workflow.draft_workspaces.get",
@@ -710,6 +732,8 @@ async def test_rpc_draft_workspace_focused_edit_methods(tmp_path) -> None:
     assert routed["result"]["revision"] == 3
     assert input_mapped["result"]["revision"] == 4
     assert output_mapped["result"]["revision"] == 5
+    assert input_merged["result"]["revision"] == 6
+    assert output_merged["result"]["revision"] == 7
     draft = fetched["result"]["draft"]
     assert draft["name"] == "focused_renamed"
     assert draft["routes"]["call"]["ok"] == "__end__"
@@ -717,13 +741,21 @@ async def test_rpc_draft_workspace_focused_edit_methods(tmp_path) -> None:
         {
             "target": {"root": "local", "parts": ["value"]},
             "path": {"root": "input", "parts": ["value"]},
-        }
+        },
+        {
+            "target": {"root": "local", "parts": ["extra"]},
+            "path": {"root": "input", "parts": ["extra"]},
+        },
     ]
     assert draft["steps"]["call"]["output"] == [
         {
             "source": {"root": "local", "parts": ["value"]},
             "target": {"root": "state", "parts": ["value"]},
-        }
+        },
+        {
+            "source": {"root": "local", "parts": ["extra"]},
+            "target": {"root": "state", "parts": ["extra"]},
+        },
     ]
 
 

tests/wf_transport_rpc_http/test_client.py

@@ -487,11 +487,27 @@ async def test_rpc_client_draft_workspace_focused_edit_methods(tmp_path) -> None
             step_id="call",
             output_map={"value": "state.value"},
         )
+        input_merged = await client.set_step_input_map(
+            workspace_id="client_focused_ws",
+            revision=5,
+            step_id="call",
+            input_map={"input.extra": "extra"},
+            merge=True,
+        )
+        output_merged = await client.set_step_output_map(
+            workspace_id="client_focused_ws",
+            revision=6,
+            step_id="call",
+            output_map={"extra": "state.extra"},
+            merge=True,
+        )
 
     assert named["revision"] == 2
     assert routed["revision"] == 3
     assert input_mapped["revision"] == 4
     assert output_mapped["revision"] == 5
+    assert input_merged["revision"] == 6
+    assert output_merged["revision"] == 7
 
 
 async def test_rpc_client_diagnoses_source(tmp_path) -> None: