end to end fix by Validating the plan

src/wf_artifacts/factory.py

@@ -2,6 +2,8 @@ from __future__ import annotations
 
 from collections.abc import Mapping
 
+from wf_core import Workflow
+
 from .models import JsonObject, RequiredCapability, WorkflowArtifact
 
 
@@ -17,6 +19,7 @@ def create_workflow_artifact_from_plan(
     created_from_catalog_version: str | None = None,
 ) -> WorkflowArtifact:
     """Create an immutable artifact from a declarative workflow plan."""
+    _validate_workflow_plan(plan)
     return WorkflowArtifact(
         id=artifact_id,
         version=version,
@@ -36,3 +39,30 @@ def _required_object_field(plan: JsonObject, field_name: str) -> JsonObject:
     if not isinstance(value, dict):
         raise ValueError(f"workflow plan is missing object field {field_name!r}")
     return value
+
+
+def _validate_workflow_plan(plan: JsonObject) -> None:
+    try:
+        workflow = Workflow.model_validate(plan)
+    except Exception as exc:
+        raise ValueError(f"invalid workflow plan: {exc}") from exc
+
+    node_ids = {node.id for node in workflow.nodes}
+    if workflow.start not in node_ids:
+        raise ValueError(
+            f"invalid workflow plan: start node {workflow.start!r} does not exist"
+        )
+
+    # wf_core currently uses Workflow.start as the only entry-point source.
+    # START is exported for future LangGraph-style edges, but core validation
+    # does not accept START edges yet.
+    edge_sources = set(node_ids)
+    for edge in workflow.edges:
+        if edge.from_ not in edge_sources:
+            raise ValueError(
+                f"invalid workflow plan: edge source {edge.from_!r} does not exist"
+            )
+        if edge.to not in node_ids and edge.to != "__end__":
+            raise ValueError(
+                f"invalid workflow plan: edge destination {edge.to!r} does not exist"
+            )

tests/artifacts/test_factory.py

@@ -50,6 +50,43 @@ def test_create_workflow_artifact_from_plan_rejects_missing_boundary_schema() ->
         raise AssertionError("expected missing output_schema to be rejected")
 
 
+def test_create_workflow_artifact_from_plan_rejects_invalid_workflow_shape() -> None:
+    plan = _plan()
+    plan["state_schema"] = {"fields": {"echoed": {"schema": {"type": "string"}}}}
+
+    try:
+        create_workflow_artifact_from_plan(
+            artifact_id="echo",
+            version=1,
+            title="Echo",
+            plan=plan,
+            outcomes=("done",),
+        )
+    except ValueError as exc:
+        assert "state_schema" in str(exc)
+        assert "type" in str(exc)
+    else:
+        raise AssertionError("expected invalid state schema to be rejected")
+
+
+def test_create_workflow_artifact_from_plan_rejects_missing_start_node() -> None:
+    plan = _plan()
+    plan["start"] = "missing"
+
+    try:
+        create_workflow_artifact_from_plan(
+            artifact_id="echo",
+            version=1,
+            title="Echo",
+            plan=plan,
+            outcomes=("done",),
+        )
+    except ValueError as exc:
+        assert "start node 'missing' does not exist" in str(exc)
+    else:
+        raise AssertionError("expected missing start node to be rejected")
+
+
 def _plan() -> dict[str, object]:
     return {
         "name": "echo",
@@ -65,6 +102,14 @@ def _plan() -> dict[str, object]:
             "required": ["echoed"],
         },
         "start": "echo",
-        "nodes": [],
+        "nodes": [
-        "edges": [],
+            {
+                "id": "echo",
+                "type": "node",
+                "node": "demo.echo_tool",
+                "in_map": {"input.text": "text"},
+                "out_map": {"echoed": "state.echoed"},
+            }
+        ],
+        "edges": [{"from": "echo", "outcome": "ok", "to": "__end__"}],
     }

tests/wf_mcp/test_broker_server.py

@@ -360,7 +360,9 @@ def test_broker_saves_and_lists_workflow_deployments() -> None:
 
 
 def test_broker_runs_non_interrupting_workflow_deployment() -> None:
-    artifact_store = FileWorkflowArtifactStore(local_temp_root() / "broker_run_artifacts")
+    artifact_store = FileWorkflowArtifactStore(
+        local_temp_root() / "broker_run_artifacts"
+    )
     artifact_store.save_artifact(_echo_artifact())
     artifact_store.save_deployment(
         WorkflowDeployment(

wf_mcp.config.json

@@ -14,17 +14,15 @@
       }
     },
     {
-      "id": "serena.default",
+      "id": "playwright.default",
-      "server": "serena",
+      "server": "playwright",
       "account": "default",
       "enabled": true,
       "metadata": {
         "transport": "stdio",
-        "command": "serena",
+        "command": "pnpx",
         "args": [
-          "start-mcp-server",
+            "@playwright/mcp@latest"
-          "--enable-web-dashboard=true",
-          "--project-from-cwd"
         ],
         "env": {}
       }