Implement saved native subgraph resolution through deployments

docs/current_roadmap.md

@@ -45,8 +45,7 @@ implementation state.
   [ADR 0002](./adr/0002-concurrent-foreach-policy-and-barrier-commits.md).
 - Native subgraph design spec:
   [2026-05-24 native subgraphs](./superpowers/specs/2026-05-24-native-subgraphs-design.md).
-- **Native subgraphs / graph-as-node**: next major runtime feature. The
+- **Native subgraphs / graph-as-node**: core has `SubgraphNode`, structural
-  scaffolding slice is complete: core has `SubgraphNode`, structural
   `WorkflowRef`, workflow-level outcomes plus explicit `EndNode` termination,
   authoring helpers (`subgraph_ref` / `WorkflowBuilder.subgraph`), and artifact
   reference conversion helpers. Core can now execute a prepared local child
@@ -54,11 +53,16 @@ implementation state.
   map child output through the boundary, and route by the child's terminal
   outcome. Prepared child interrupts now bubble through a typed internal route
   and resume inside child scope while the public request identifies the parent
-  subgraph boundary. Saved/deployed child resolution remains next. Wrapper
+  subgraph boundary. The workflow platform now resolves non-interrupting saved
-  helpers currently run child workflows as ordinary nodes; native
+  child artifact refs into native prepared dependencies; descendant logical
+  capabilities inherit the root deployment binding environment, and missing or
+  cyclic saved children fail validation before a run starts. Wrapper helpers
+  currently run child workflows as ordinary nodes; native
   `SubgraphNode` is now the graph-as-node path for prepared children.
   `WorkflowBuilder.prepare_subgraph()` and `WorkflowBuilder.resume()` make the
   local runnable/resumable path available without core-runtime plumbing.
+  Saved interrupting artifacts remain unrunnable through one-shot
+  `run_deployment` until the platform exposes persisted resume.
 - **Concurrent foreach**: implemented in core with explicit scheduling,
   reducer/merge semantics, item error policy, async handler batching, and
   quiescent interrupt behavior. Remaining work is polish and future reuse of
@@ -100,8 +104,9 @@ Frame stress points remaining for native subgraphs and future fork/gather:
 ## Why This Order
 
 The MCP workflow authoring path is now usable enough for real testing. The next
-bottleneck is runtime/platform correctness: resumable child execution,
+bottleneck is runtime/platform correctness: persisted resume for saved
-saved/deployed child resolution, persistent run history, and protocol-native
+interrupting children, optional per-use-site child deployment overrides,
-progress reporting. Concurrent foreach and prepared native child execution now
+persistent run history, and protocol-native progress reporting. Concurrent
-supply scheduler/lineage precedent. Those remaining pieces should come before
+foreach and native saved child execution now supply scheduler/lineage
-adding more high-level authoring sugar.
+precedent. Those remaining pieces should come before adding more high-level
+authoring sugar.

docs/superpowers/plans/2026-05-25-native-subgraph-interrupt-resume.md

@@ -13,6 +13,7 @@
 ### Task 1: Child Interrupt Contract
 
 **Files:**
+
 - Modify: `src/wf_core/run_state.py`
 - Modify: `tests/core/test_subgraph_step.py`
 
@@ -54,6 +55,7 @@ to use `route=None`.
 ### Task 2: Scope-Aware Interrupt Creation and Resume
 
 **Files:**
+
 - Modify: `src/wf_core/runtime/ops/handlers.py`
 - Modify: `src/wf_core/runtime/ops/interrupts.py`
 - Modify: `src/wf_core/runtime/preparation.py`
@@ -83,6 +85,7 @@ output into parent state.
 ### Task 3: Verification and Documentation
 
 **Files:**
+
 - Modify: `docs/wf_core_architecture.md`
 - Modify: `docs/current_roadmap.md`
 

docs/superpowers/plans/2026-05-25-saved-subgraph-platform-resolution.md

@@ -0,0 +1,397 @@
+# Saved Subgraph Platform Resolution Implementation Plan
+
+> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.
+
+**Goal:** Execute non-interrupting saved child workflow artifacts natively from a parent deployment while resolving all descendant dependencies through the parent deployment binding environment.
+
+**Architecture:** `wf_core` remains unaware of artifact storage: it only looks up caller-prepared `PreparedSubgraph` dependencies by structural workflow-ref display key. A new focused workflow-surface resolver loads exact child artifact versions, traverses descendants with cycle detection, validates descendant capabilities and existing interrupt limitations, and prepares child workflows for `WfMcpService` execution. Future child deployment overrides remain outside this slice and must be keyed by subgraph use site, not artifact identity.
+
+**Tech Stack:** Python 3.14, Pydantic v2, `wf_core` native subgraphs, `wf_artifacts` stores/deployment diagnostics, `wf_mcp` workflow surface, pytest, ruff, basedpyright.
+
+---
+
+## File Structure
+
+- Modify `src/wf_core/runtime/subgraphs.py`: accept a caller-prepared structural saved `WorkflowRef`; do not load artifacts.
+- Create `src/wf_mcp/workflow_surface/saved_subgraphs.py`: own saved-child traversal, diagnostic production, and preparation of executable child dependencies.
+- Modify `src/wf_mcp/workflow_surface/handlers.py`: include descendant dependency/interrupt diagnostics in deployment validation.
+- Modify `src/wf_mcp/broker/service/core.py`: supply prepared saved children to `execute_workflow_async`.
+- Modify `tests/core/test_subgraph_step.py`: cover core execution of an already-prepared saved ref.
+- Create `tests/wf_mcp/test_saved_subgraphs.py`: cover deployment-bound saved child execution and unrunnable descendant cases.
+- Modify `docs/current_roadmap.md` and `docs/workflow_artifacts.md`: record the new runnable saved-child path and remaining persisted-resume limitation.
+
+### Task 1: Core Accepts Prepared Saved References
+
+**Files:**
+
+- Modify: `src/wf_core/runtime/subgraphs.py`
+- Test: `tests/core/test_subgraph_step.py`
+
+- [ ] **Step 1: Write the failing core test**
+
+Add a test that constructs a parent `SubgraphNode` with:
+
+```python
+workflow=WorkflowRef(artifact_id="child", version=1)
+```
+
+and supplies:
+
+```python
+subgraphs={
+    "workflow.child.v1": PreparedSubgraph(
+        workflow=child,
+        registry={"echo": echo_handler},
+        reducers={},
+    )
+}
+```
+
+Assert the parent run completes and maps the child output into parent state.
+
+- [ ] **Step 2: Run the core test to verify it fails**
+
+Run:
+
+```bash
+uv run pytest -q tests/core/test_subgraph_step.py
+```
+
+Expected: FAIL because `resolve_prepared_subgraph()` currently rejects a saved structural ref before checking supplied prepared dependencies.
+
+- [ ] **Step 3: Make prepared dependency lookup structural**
+
+Update `resolve_prepared_subgraph()`:
+
+```python
+def resolve_prepared_subgraph(
+    ref: WorkflowRef,
+    subgraphs: Mapping[str, PreparedSubgraph[HandlerT]] | None,
+) -> PreparedSubgraph[HandlerT]:
+    """Resolve a caller-prepared child; artifact loading is not a core concern."""
+    key = ref.name if ref.name is not None else ref.display
+    prepared = None if subgraphs is None else subgraphs.get(key)
+    if prepared is None:
+        raise WorkflowExecutionError(
+            f"no prepared child workflow registered for {ref.display!r}"
+        )
+    return prepared
+```
+
+- [ ] **Step 4: Run the core test to verify it passes**
+
+Run:
+
+```bash
+uv run pytest -q tests/core/test_subgraph_step.py
+```
+
+Expected: PASS.
+
+### Task 2: Traverse and Prepare Saved Child Artifacts
+
+**Files:**
+
+- Create: `src/wf_mcp/workflow_surface/saved_subgraphs.py`
+- Test: `tests/wf_mcp/test_saved_subgraphs.py`
+
+- [ ] **Step 1: Write failing traversal tests**
+
+Add focused tests for a helper that receives a root artifact plan containing a
+structural `SubgraphNode` ref and a `FileWorkflowArtifactStore`:
+
+```python
+resolution = resolve_saved_subgraph_tree(
+    root_artifact=parent,
+    artifact_store=artifact_store,
+)
+assert resolution.artifacts_by_ref["workflow.child.v1"].id == "child"
+assert resolution.diagnostics == []
+```
+
+Add tests asserting:
+
+```python
+assert resolution.diagnostics[0].code == "workflow_dependency_missing"
+assert resolution.diagnostics[0].code == "workflow_dependency_cycle"
+```
+
+for a missing child and a parent/child cycle respectively.
+
+- [ ] **Step 2: Run tests to verify they fail**
+
+Run:
+
+```bash
+uv run pytest -q tests/wf_mcp/test_saved_subgraphs.py
+```
+
+Expected: FAIL because `saved_subgraphs.py` and its resolver do not exist.
+
+- [ ] **Step 3: Implement saved-child tree discovery**
+
+Create a typed resolution object:
+
+```python
+@dataclass(frozen=True, slots=True)
+class SavedSubgraphTree:
+    """Saved descendant artifacts keyed by structural workflow-ref display."""
+
+    artifacts_by_ref: dict[str, WorkflowArtifact]
+    diagnostics: list[DependencyDiagnostic]
+```
+
+Implement:
+
+```python
+def resolve_saved_subgraph_tree(
+    *,
+    root_artifact: WorkflowArtifact,
+    artifact_store: WorkflowArtifactStore,
+) -> SavedSubgraphTree:
+    """Load exact saved descendants and report missing refs or cycles."""
+```
+
+Parse each artifact plan as `RawWorkflowPlan`, visit only `SubgraphNode`
+instances whose `workflow.artifact_id` and `.version` are present, load the
+exact artifact, and recurse. Keep an active artifact stack of
+`(artifact_id, version)` values so only recursion cycles fail; repeated reuse
+of the same child in separate branches is allowed.
+
+Construct direct diagnostics without inventing a fake capability:
+
+```python
+DependencyDiagnostic(
+    severity=DiagnosticSeverity.ERROR,
+    code="workflow_dependency_missing",
+    logical_ref=ref.display,
+    message=f"Saved child workflow {ref.display!r} is unavailable.",
+    repair_hint="Save the referenced artifact version or update the parent graph.",
+)
+```
+
+Use analogous text for `workflow_dependency_cycle`.
+
+- [ ] **Step 4: Run traversal tests to verify they pass**
+
+Run:
+
+```bash
+uv run pytest -q tests/wf_mcp/test_saved_subgraphs.py
+```
+
+Expected: traversal tests PASS.
+
+### Task 3: Validate Descendants Under One Deployment Environment
+
+**Files:**
+
+- Modify: `src/wf_mcp/workflow_surface/saved_subgraphs.py`
+- Modify: `src/wf_mcp/workflow_surface/handlers.py`
+- Test: `tests/wf_mcp/test_saved_subgraphs.py`
+
+- [ ] **Step 1: Write failing public-validation tests**
+
+Add tests that save a parent artifact referencing a child artifact whose plan
+uses logical node `demo.echo_tool`. Save one parent deployment:
+
+```python
+WorkflowDeployment(
+    id="parent.personal",
+    artifact_id="parent",
+    artifact_version=1,
+    bindings={"demo": "demo.personal"},
+)
+```
+
+Assert:
+
+```python
+result = asyncio.run(handlers.validate_deployment(deployment_id="parent.personal"))
+assert result["status"] == "runnable"
+```
+
+Add descendant failure assertions:
+
+```python
+assert result["diagnostics"][0]["code"] == "binding_missing"
+assert result["diagnostics"][0]["logical_ref"] == "demo.echo_tool"
+```
+
+and for an interrupting saved child:
+
+```python
+assert result["status"] == "unrunnable"
+assert result["diagnostics"][0]["code"] == "unsupported_interrupt"
+```
+
+The interrupt diagnostic must be reported before execution because
+`run_deployment` is still one-shot.
+
+- [ ] **Step 2: Run validation tests to verify they fail**
+
+Run:
+
+```bash
+uv run pytest -q tests/wf_mcp/test_saved_subgraphs.py
+```
+
+Expected: FAIL because `_deployment_validation()` validates only the root artifact.
+
+- [ ] **Step 3: Add descendant validation composition**
+
+Add a helper in `saved_subgraphs.py`:
+
+```python
+def validate_saved_subgraph_tree(
+    *,
+    tree: SavedSubgraphTree,
+    deployment: WorkflowDeployment,
+    sources: list[AvailableSource],
+    unsupported_interrupt: Callable[[WorkflowArtifact], DependencyDiagnostic | None],
+) -> list[DependencyDiagnostic]:
+    """Validate descendants in the root deployment environment."""
+```
+
+It should begin with tree discovery diagnostics, then for each loaded child
+call `validate_deployment_dependencies(...)`, and finally append the existing
+unsupported-interrupt diagnostic for that child when present.
+
+Update `WorkflowSurfaceHandlers._deployment_validation()` to discover the
+saved tree and extend the root diagnostic list with descendant diagnostics.
+Preserve the root artifact interrupt check in `run_deployment()`; it remains
+the existing surface behavior.
+
+- [ ] **Step 4: Run validation tests to verify they pass**
+
+Run:
+
+```bash
+uv run pytest -q tests/wf_mcp/test_saved_subgraphs.py
+```
+
+Expected: descendant validation tests PASS.
+
+### Task 4: Execute Prepared Saved Children
+
+**Files:**
+
+- Modify: `src/wf_mcp/workflow_surface/saved_subgraphs.py`
+- Modify: `src/wf_mcp/broker/service/core.py`
+- Test: `tests/wf_mcp/test_saved_subgraphs.py`
+
+- [ ] **Step 1: Write failing end-to-end execution tests**
+
+Use the parent deployment and child artifact from Task 3. Assert:
+
+```python
+payload = asyncio.run(
+    handlers.run_deployment(
+        deployment_id="parent.personal",
+        workflow_input={"text": "hello"},
+    )
+)
+assert payload["status"] == "completed"
+assert payload["output"]["echoed"] == "hello"
+```
+
+Add a nested parent -> middle -> child test where only the parent deployment
+contains `{"demo": "demo.personal"}`, and assert the grandchild node executes
+through the inherited binding.
+
+- [ ] **Step 2: Run execution tests to verify they fail**
+
+Run:
+
+```bash
+uv run pytest -q tests/wf_mcp/test_saved_subgraphs.py
+```
+
+Expected: FAIL because the service does not provide prepared saved children to core.
+
+- [ ] **Step 3: Prepare executable children and supply them to core**
+
+Add:
+
+```python
+def prepare_saved_subgraphs(
+    *,
+    tree: SavedSubgraphTree,
+    deployment: WorkflowDeployment | None,
+    sources: dict[str, CapabilitySource],
+    compile_plan: Callable[[RawWorkflowPlan, dict[str, str] | None], Workflow],
+) -> dict[str, PreparedSubgraph[AsyncRegistryHandler]]:
+    """Compile loaded descendants with the parent deployment bindings."""
+```
+
+For each child artifact, parse its plan, resolve its node/reducer runtime
+dependencies with `resolve_runtime_dependencies(...)`, compile it, and return
+the dependency under its structural ref display key:
+
+```python
+prepared[workflow_ref_display] = PreparedSubgraph(
+    workflow=compile_plan(plan, dependencies.node_name_bindings),
+    registry=dependencies.node_registry,
+    reducers=dependencies.reducers,
+)
+```
+
+Update `WfMcpService.run_workflow_from_plan()` to resolve the saved tree for
+`runtime_artifact` when an artifact store exists, prepare loaded children, and
+pass:
+
+```python
+subgraphs=prepared_subgraphs
+```
+
+to `execute_workflow_async(...)`.
+
+- [ ] **Step 4: Run saved-child tests to verify they pass**
+
+Run:
+
+```bash
+uv run pytest -q tests/wf_mcp/test_saved_subgraphs.py
+```
+
+Expected: all saved-subgraph tests PASS.
+
+### Task 5: Documentation and Full Verification
+
+**Files:**
+
+- Modify: `docs/current_roadmap.md`
+- Modify: `docs/workflow_artifacts.md`
+
+- [ ] **Step 1: Document current support**
+
+Record:
+
+- Non-interrupting saved child artifacts now run natively through deployments.
+- Descendant logical dependencies inherit the root deployment binding environment.
+- Missing/cyclic/interrupting saved descendants are reported as unrunnable.
+- Explicit per-child deployment overrides and persisted saved-interrupt resume remain future work.
+
+- [ ] **Step 2: Run focused and full verification**
+
+Run:
+
+```bash
+uv run pytest -q tests/core/test_subgraph_step.py tests/wf_mcp/test_saved_subgraphs.py
+uv run pytest -q
+uvx ruff check src/wf_core src/wf_mcp tests/core/test_subgraph_step.py tests/wf_mcp/test_saved_subgraphs.py
+uvx ruff format --check src/wf_core/runtime/subgraphs.py src/wf_mcp/workflow_surface/saved_subgraphs.py src/wf_mcp/workflow_surface/handlers.py src/wf_mcp/broker/service/core.py tests/core/test_subgraph_step.py tests/wf_mcp/test_saved_subgraphs.py
+uv run basedpyright --level error src/wf_core src/wf_mcp tests/core/test_subgraph_step.py tests/wf_mcp/test_saved_subgraphs.py
+```
+
+Expected: all commands pass, with the repository's intentionally skipped live
+integration test remaining skipped unless its environment is provided.
+
+## Self-Review
+
+- Spec coverage: the plan covers exact artifact loading, inherited bindings,
+  cycle/missing diagnostics, preserved interrupt rejection, and native execution.
+- Boundary check: artifact traversal and dependency preparation stay in
+  `wf_mcp`; `wf_core` accepts only caller-prepared structural refs.
+- Future compatibility: no child deployment field is added; per-use-site
+  override remains an additive future platform feature.

docs/superpowers/specs/2026-05-24-native-subgraphs-design.md

@@ -1,6 +1,7 @@
 # Native Subgraphs Design
 
-Status: prepared-child execution and interrupt resume implemented; artifact resolution planned
+Status: prepared-child execution and interrupt resume implemented; saved-artifact
+resolution scoped for platform implementation
 
 Native subgraphs should make a workflow usable as a workflow step without
 collapsing the child run into one opaque Python node call. The current
@@ -9,8 +10,10 @@ compatibility wrappers, but they hide the child trace, child frames, and child
 interrupt lifecycle from `wf_core`.
 
 This design defines the core runtime shape. The boundary model, prepared-child
-execution, and routed child interrupt resume are implemented; saved-workflow
+execution, and routed child interrupt resume are implemented. The remaining
-resolution remains planned.
+saved-workflow work is platform preparation: load immutable child artifact
+versions, resolve their runtime dependencies, and supply prepared children to
+the already-implemented core runtime.
 
 ## Goals
 
@@ -333,9 +336,10 @@ child = parent.subgraph(
 ```
 
 This copies the compiled child workflow contract into a core `SubgraphNode`,
-appends it to the builder, and returns the step for normal routing. Runtime
+appends it to the builder, and returns the step for normal routing. For a local
-execution requires the child graph and its handlers to be supplied as a
+child builder, `parent.prepare_subgraph(child_builder)` registers the compiled
-`PreparedSubgraph`; higher layers still need dependency resolution before
+graph, handlers, and reducers required by `parent.execute(...)` and
+`parent.resume(...)`. Higher layers still need dependency resolution before
 saved/deployed workflow refs can run. The lower-level `subgraph_ref(...)`
 helper exists for code that wants only the core step object.
 
@@ -382,6 +386,37 @@ The platform layer should:
 This keeps auth, source availability, deployment binding, and MCP account
 selection out of `wf_core`.
 
+### Saved Child Deployment Environment
+
+For the first saved-subgraph slice, one deployment defines the runnable
+environment for the full graph tree. A parent deployment that loads a
+structural child ref such as `{"artifact_id": "child", "version": 2}` must:
+
+1. load exactly that immutable child artifact version
+2. resolve the child's logical node and reducer dependencies using the same
+   deployment bindings as the parent
+3. recursively prepare non-interrupting descendant child artifacts using that
+   same environment
+4. detect missing artifacts, missing bound capabilities, and saved-child
+   reference cycles before execution
+
+This intentionally does not add a child deployment id to `WorkflowRef`.
+Supporting an explicit per-child deployment override later remains compatible
+with the structural child reference and preparation boundary. Such an override
+must be keyed by the parent subgraph dependency/use site, not only by child
+artifact id: one parent graph may intentionally invoke the same immutable
+child artifact twice against different accounts or capability bindings.
+
+### Saved Child Interrupt Limitation
+
+Native prepared children can interrupt and resume in core. The current
+workflow-surface `run_deployment` entrypoint is still a one-shot execution
+call, however, and does not expose persisted platform resume for a saved run.
+Therefore this slice preserves the existing unrunnable behavior for saved
+artifacts containing interrupts, including interrupting descendant artifacts.
+The platform must report that diagnostic before execution rather than starting
+a run it cannot resume through its public surface.
+
 ## Implementation Slices
 
 ### Completed Scaffold: Typed Native Boundary
@@ -424,9 +459,13 @@ selection out of `wf_core`.
 - Structural saved-workflow references and conversion helpers already exist;
   this slice is execution resolution, not a new identity shape.
 - Add platform-level resolution for saved workflow artifacts.
-- Validate dependencies and source bindings before execution.
+- Apply the parent deployment binding environment transitively to each exact
-- Tests: saved child workflow runs through a deployment binding, missing child
+  saved child artifact version.
-  artifact reports an unrunnable dependency.
+- Validate dependencies, missing artifacts, saved-child cycles, and existing
+  unsupported interrupt diagnostics before execution.
+- Tests: saved child workflow runs through a deployment binding, nested saved
+  child dependencies use the same binding environment, and missing,
+  cyclic, or interrupting child artifacts report an unrunnable dependency.
 
 ### Slice 4: Optional Policy Expansion
 
@@ -440,11 +479,8 @@ selection out of `wf_core`.
 ## Risks
 
 - Trace shape can become confusing if child entries are flattened too early.
-- Interrupt resume can become string-parsing-heavy if `InterruptRequest` is not
-  extended structurally.
 - Storing nested run state directly may bloat persisted runs unless inspection
   APIs paginate trace/state detail.
-- Recursive saved workflows need explicit cycle detection.
 - Multiple child workflow dependency registries can make runtime dependencies
   complex; keep the boundary typed early.
 
@@ -454,15 +490,15 @@ selection out of `wf_core`.
   frame metadata plus shared parent `RunState.frames`?
 - Should `TraceEntry` gain explicit `scope_id`, `lineage_id`, and parent-trace
   fields, or should child traces live in a separate inspectable structure?
-- Is v1 allowed to reference only inline/compiled child workflows, or should it
-  immediately accept artifact refs resolved by the platform?
 
 ## Recommendation
 
-The typed boundary scaffold and non-interrupting prepared-child runtime are
+The typed boundary scaffold, prepared-child runtime, and routed interrupt
-complete. Do not delete the wrapper-node helpers yet; use them as compatibility
+resume are complete. Implement Slice 3 in the platform layer: prepare saved
-and examples while native subgraphs mature.
+non-interrupting child artifacts recursively under one deployment environment
+and pass those prepared dependencies into core execution.
 
-Implement Slice 2 before exposing saved workflows as broadly reusable child
+Do not broaden saved interrupt support through `run_deployment` until the
-graphs. Saved workflows without nested interrupt support would look reusable
+platform has a public persisted resume path. Do not delete wrapper-node
-but break at exactly the moment users need persistence and resume.
+helpers yet; they remain compatibility APIs while saved native execution
+matures.

docs/wf_core_architecture.md

@@ -139,8 +139,10 @@ limits and intended adapter seam.
   dependencies. A prepared local child executes through a child runtime scope
   and lineage; child output commits only through declared boundary bindings and
   the parent routes by the child's terminal workflow outcome. Saved/deployed
-  workflow resolution remains outside core and is not implemented at this
+  workflow resolution remains outside core; the workflow platform can now
-  boundary yet. For local authoring, `WorkflowBuilder.prepare_subgraph()`
+  supply non-interrupting saved child artifacts as prepared dependencies using
+  one inherited deployment binding environment. For local authoring,
+  `WorkflowBuilder.prepare_subgraph()`
   registers a child builder and `WorkflowBuilder.resume()` continues a paused
   prepared-child interrupt without requiring direct core-runtime calls.
 - The current `wf_authoring` wrapper helpers still run child workflows as
@@ -151,14 +153,14 @@ limits and intended adapter seam.
   `examples/authoring_workflow_as_node.py` for the compatibility wrapper shape
   and `examples/authoring_native_subgraph.py` plus
   `examples/authoring_native_subgraph_interrupt.py` for the native path.
-- Saved workflow-as-node execution with interrupts still requires platform
+- Saved workflow-as-node execution with interrupts still requires a persisted
-  resolution of artifact/deployment references into prepared child
+  platform resume surface. The current one-shot deployment tool rejects those
-  dependencies before core execution begins.
+  artifacts before execution even though core prepared children can resume.
 - Frames are no longer only a serial execution stack: the runtime has a ready
   queue, `BLOCKED` frame state, lineage isolation, barrier merge semantics, and
   pending child results for concurrent foreach. Native prepared subgraphs now
-  use child-scope execution and typed routed child interruption; saved/deployed
+  use child-scope execution and typed routed child interruption; the platform
-  child resolution remains outstanding.
+  resolves non-interrupting saved/deployed child artifacts before core starts.
   Concurrent foreach is the primary current use case for async concurrent node
   handler execution.
 - Runtime errors are still ordinary exceptions plus failed run status. A richer

docs/workflow_artifacts.md

@@ -73,6 +73,17 @@ Current `run_deployment` calls are synchronous request/response executions. They
 return compact status, output, diagnostics, and `trace_count`; optional ranged
 trace detail is for debugging only.
 
+Non-interrupting saved workflow children can now execute natively through this
+deployment surface. A parent deployment resolves its saved descendants by exact
+artifact version, and the parent binding environment supplies logical source
+bindings for the whole child tree. This is intentionally one configured graph
+environment; future per-child deployment overrides, if added, must be keyed by
+the subgraph use site rather than only the child artifact id.
+
+Interrupting saved artifacts remain unrunnable through `run_deployment`.
+Although core prepared children can interrupt and resume, this one-shot public
+surface does not yet persist a run for a later resume request.
+
 Future run history should introduce a stable `run_id` only when there is a real
 run store behind it. A `run_id` without persisted state, trace paging, and
 status lookup would be misleading. The likely shape is:

src/wf_core/runtime/subgraphs.py

@@ -96,15 +96,17 @@ def resolve_prepared_subgraph(
     ref: WorkflowRef,
     subgraphs: Mapping[str, PreparedSubgraph[HandlerT]] | None,
 ) -> PreparedSubgraph[HandlerT]:
-    """Resolve a prepared local child; artifact loading is not a core concern."""
+    """Resolve a caller-prepared child; artifact loading is not a core concern.
-    if ref.name is None:
+
-        raise WorkflowExecutionError(
+    Local refs use their registry name. Saved refs use their structural display
-            f"saved child workflow reference {ref.display!r} is not prepared for core execution"
+    key only as an already-prepared dependency lookup key; loading immutable
-        )
+    artifacts and resolving deployment bindings remains platform work.
-    prepared = None if subgraphs is None else subgraphs.get(ref.name)
+    """
+    key = ref.name if ref.name is not None else ref.display
+    prepared = None if subgraphs is None else subgraphs.get(key)
     if prepared is None:
         raise WorkflowExecutionError(
-            f"no prepared child workflow registered for {ref.name!r}"
+            f"no prepared child workflow registered for {ref.display!r}"
         )
     return prepared
 

src/wf_mcp/broker/service/core.py

@@ -48,6 +48,10 @@ from ...shared.names import RESERVED_CONNECTION_IDS
 from ...storage import Store
 from ...workflow.wrappers import _model_from_schema
 from ...workflow_surface.runtime_dependencies import resolve_runtime_dependencies
+from ...workflow_surface.saved_subgraphs import (
+    prepare_saved_subgraphs,
+    resolve_saved_subgraph_tree,
+)
 from ..admin_capabilities import admin_source
 from ..catalog import CombinedCatalog, snapshot_from_specs
 from ..discovery import discover_connection_capabilities, specs_from_discovered_tools
@@ -698,12 +702,25 @@ class WfMcpService:
             sources=self.capability_sources,
             plan_node_names=plan_node_names,
         )
+        prepared_subgraphs = {}
+        if artifact is not None and self.artifact_store is not None:
+            tree = resolve_saved_subgraph_tree(
+                root_artifact=artifact,
+                artifact_store=self.artifact_store,
+            )
+            prepared_subgraphs = prepare_saved_subgraphs(
+                tree=tree,
+                deployment=deployment,
+                sources=self.capability_sources,
+                compile_plan=self.compile_plan,
+            )
         workflow = self.compile_plan(plan, dependencies.node_name_bindings)
         run = await execute_workflow_async(
             workflow,
             workflow_input,
             dependencies.node_registry,
             reducers=dependencies.reducers,
+            subgraphs=prepared_subgraphs,
         )
         self._record_event(
             make_event(

src/wf_mcp/workflow_surface/handlers.py

@@ -9,7 +9,6 @@ from wf_artifacts import (
     AvailableCapability,
     AvailableSource,
     DependencyDiagnostic,
-    DiagnosticSeverity,
     DraftWorkspaceStore,
     RequiredCapability,
     WorkflowArtifact,
@@ -52,6 +51,11 @@ from .constants import (
 )
 from .models import TraceRange
 from .refs import parse_workflow_surface_capability_id
+from .saved_subgraphs import (
+    interrupting_artifact_diagnostic,
+    resolve_saved_subgraph_tree,
+    validate_saved_subgraph_tree,
+)
 from .wrapper_hints import wrapper_hints_for_capability
 
 if TYPE_CHECKING:
@@ -279,13 +283,13 @@ class WorkflowSurfaceHandlers:
         deployment_id: str | None,
     ) -> dict[str, Any]:
         """Execute a saved wrapper artifact through the workflow runner."""
-        unsupported = _unsupported_interrupt_diagnostic(artifact)
+        unsupported = interrupting_artifact_diagnostic(artifact)
         if unsupported is not None:
             raise ValueError(unsupported.message)
 
-        # For now only wrapper artifacts are honest node capabilities here.
+        # Direct capability calls remain wrapper-only. Full saved workflows run
-        # Full saved workflows stay on `run_deployment` until core supports
+        # through deployments, where native subgraph dependencies and bindings
-        # graph-as-node semantics instead of us faking subgraphs at this layer.
+        # are prepared before core execution.
         plan = _raw_plan_from_artifact(artifact)
         deployment = None
         if deployment_id is not None:
@@ -882,7 +886,7 @@ class WorkflowSurfaceHandlers:
                 diagnostics=diagnostics,
             )
 
-        unsupported = _unsupported_interrupt_diagnostic(artifact)
+        unsupported = interrupting_artifact_diagnostic(artifact)
         if unsupported is not None:
             return _run_payload(
                 deployment=deployment,
@@ -933,10 +937,22 @@ class WorkflowSurfaceHandlers:
             deployment.artifact_id,
             deployment.artifact_version,
         )
+        available_sources = _available_sources(self.service)
         diagnostics = validate_deployment_dependencies(
             artifact=artifact,
             deployment=deployment,
-            sources=_available_sources(self.service),
+            sources=available_sources,
+        )
+        tree = resolve_saved_subgraph_tree(
+            root_artifact=artifact,
+            artifact_store=self.service.artifact_store,
+        )
+        diagnostics.extend(
+            validate_saved_subgraph_tree(
+                tree=tree,
+                deployment=deployment,
+                sources=available_sources,
+            )
         )
         return deployment, artifact, diagnostics
 
@@ -1212,26 +1228,6 @@ def _plan_field(artifact: WorkflowArtifact, field_name: str) -> Any:
         ) from exc
 
 
-def _unsupported_interrupt_diagnostic(
-    artifact: WorkflowArtifact,
-) -> DependencyDiagnostic | None:
-    if not any(node.get("type") == "interrupt" for node in _plan_nodes(artifact)):
-        return None
-    return DependencyDiagnostic(
-        severity=DiagnosticSeverity.ERROR,
-        code="interrupting_artifact_unsupported",
-        logical_ref=f"workflow.{artifact.id}.v{artifact.version}",
-        message=(
-            "Running saved workflow artifacts with interrupt nodes is unsupported "
-            "until nested run-state resume is implemented."
-        ),
-        repair_hint=(
-            "Run this workflow as a top-level core workflow or remove interrupt "
-            "nodes before saving it as a runnable deployment."
-        ),
-    )
-
-
 def _plan_nodes(artifact: WorkflowArtifact) -> list[dict[str, Any]]:
     nodes = artifact.plan.get("nodes", [])
     return [node for node in nodes if isinstance(node, dict)]

src/wf_mcp/workflow_surface/saved_subgraphs.py

@@ -0,0 +1,219 @@
+from __future__ import annotations
+
+from collections.abc import Callable
+from dataclasses import dataclass
+
+from pydantic import TypeAdapter
+
+from wf_artifacts import (
+    AvailableSource,
+    DependencyDiagnostic,
+    DiagnosticSeverity,
+    WorkflowArtifact,
+    WorkflowArtifactStore,
+    WorkflowDeployment,
+    validate_deployment_dependencies,
+)
+from wf_core import (
+    AsyncNodeHandler,
+    InterruptNode,
+    NodeUse,
+    PreparedSubgraph,
+    SubgraphNode,
+    Workflow,
+)
+from wf_core.models.steps import Step
+from wf_core.models.workflow_refs import WorkflowRef
+from wf_platform import CapabilitySource
+
+from ..models import RawWorkflowPlan
+from .runtime_dependencies import resolve_runtime_dependencies
+
+_STEPS_ADAPTER = TypeAdapter(list[Step])
+
+
+@dataclass(frozen=True, slots=True)
+class SavedSubgraphTree:
+    """Saved descendant artifacts prepared from one root artifact boundary."""
+
+    artifacts_by_ref: dict[str, WorkflowArtifact]
+    diagnostics: list[DependencyDiagnostic]
+
+
+def resolve_saved_subgraph_tree(
+    *,
+    root_artifact: WorkflowArtifact,
+    artifact_store: WorkflowArtifactStore,
+) -> SavedSubgraphTree:
+    """Load exact saved descendants and report missing refs or recursion cycles.
+
+    A saved subgraph ref identifies an immutable artifact version. This loader
+    intentionally does not resolve capabilities or deployment bindings; it
+    identifies the artifact tree that later platform validation/preparation
+    will operate on.
+    """
+    artifacts_by_ref: dict[str, WorkflowArtifact] = {}
+    diagnostics: list[DependencyDiagnostic] = []
+    _visit_saved_children(
+        artifact=root_artifact,
+        artifact_store=artifact_store,
+        active={(root_artifact.id, root_artifact.version)},
+        artifacts_by_ref=artifacts_by_ref,
+        diagnostics=diagnostics,
+    )
+    return SavedSubgraphTree(
+        artifacts_by_ref=artifacts_by_ref,
+        diagnostics=diagnostics,
+    )
+
+
+def validate_saved_subgraph_tree(
+    *,
+    tree: SavedSubgraphTree,
+    deployment: WorkflowDeployment,
+    sources: list[AvailableSource],
+) -> list[DependencyDiagnostic]:
+    """Validate saved descendants under the parent deployment environment."""
+    diagnostics = list(tree.diagnostics)
+    for child in tree.artifacts_by_ref.values():
+        diagnostics.extend(
+            validate_deployment_dependencies(
+                artifact=child,
+                deployment=deployment,
+                sources=sources,
+            )
+        )
+        interrupt_diagnostic = interrupting_artifact_diagnostic(child)
+        if interrupt_diagnostic is not None:
+            diagnostics.append(interrupt_diagnostic)
+    return diagnostics
+
+
+def prepare_saved_subgraphs(
+    *,
+    tree: SavedSubgraphTree,
+    deployment: WorkflowDeployment | None,
+    sources: dict[str, CapabilitySource],
+    compile_plan: Callable[[RawWorkflowPlan, dict[str, str] | None], Workflow],
+) -> dict[str, PreparedSubgraph[AsyncNodeHandler]]:
+    """Compile saved descendants using one inherited deployment environment.
+
+    The tree has already fixed exact artifact versions. Binding resolution is
+    deliberately shared with the root deployment; per-use-site deployment
+    overrides are a future platform feature rather than an implicit fallback.
+    """
+    if tree.diagnostics:
+        messages = "; ".join(diagnostic.message for diagnostic in tree.diagnostics)
+        raise ValueError(f"cannot prepare invalid saved subgraph tree: {messages}")
+
+    prepared: dict[str, PreparedSubgraph[AsyncNodeHandler]] = {}
+    for ref_display, child in tree.artifacts_by_ref.items():
+        plan = RawWorkflowPlan.model_validate(child.plan)
+        dependencies = resolve_runtime_dependencies(
+            artifact=child,
+            deployment=deployment,
+            sources=sources,
+            plan_node_names=[
+                node.node for node in plan.nodes if isinstance(node, NodeUse)
+            ],
+        )
+        prepared[ref_display] = PreparedSubgraph(
+            workflow=compile_plan(plan, dependencies.node_name_bindings),
+            registry=dependencies.node_registry,
+            reducers=dependencies.reducers,
+        )
+    return prepared
+
+
+def interrupting_artifact_diagnostic(
+    artifact: WorkflowArtifact,
+) -> DependencyDiagnostic | None:
+    """Reject saved interrupt workflows until the platform exposes resume."""
+    if not any(isinstance(node, InterruptNode) for node in _artifact_steps(artifact)):
+        return None
+    return DependencyDiagnostic(
+        severity=DiagnosticSeverity.ERROR,
+        code="interrupting_artifact_unsupported",
+        logical_ref=f"workflow.{artifact.id}.v{artifact.version}",
+        message=(
+            "Running saved workflow artifacts with interrupt nodes is unsupported "
+            "until nested run-state resume is implemented."
+        ),
+        repair_hint=(
+            "Run this workflow as a top-level core workflow or remove interrupt "
+            "nodes before saving it as a runnable deployment."
+        ),
+    )
+
+
+def _visit_saved_children(
+    *,
+    artifact: WorkflowArtifact,
+    artifact_store: WorkflowArtifactStore,
+    active: set[tuple[str, int]],
+    artifacts_by_ref: dict[str, WorkflowArtifact],
+    diagnostics: list[DependencyDiagnostic],
+) -> None:
+    for ref in _saved_child_refs(artifact):
+        identity = _saved_identity(ref)
+        if identity in active:
+            diagnostics.append(_cycle_diagnostic(ref))
+            continue
+        if ref.display in artifacts_by_ref:
+            continue
+        try:
+            child = artifact_store.get_artifact(*identity)
+        except KeyError:
+            diagnostics.append(_missing_diagnostic(ref))
+            continue
+        artifacts_by_ref[ref.display] = child
+        _visit_saved_children(
+            artifact=child,
+            artifact_store=artifact_store,
+            active=active | {identity},
+            artifacts_by_ref=artifacts_by_ref,
+            diagnostics=diagnostics,
+        )
+
+
+def _saved_child_refs(artifact: WorkflowArtifact) -> list[WorkflowRef]:
+    return [
+        node.workflow
+        for node in _artifact_steps(artifact)
+        if isinstance(node, SubgraphNode) and node.workflow.artifact_id is not None
+    ]
+
+
+def _artifact_steps(artifact: WorkflowArtifact) -> list[Step]:
+    """Validate only step payloads needed for dependency discovery."""
+    raw_nodes = artifact.plan.get("nodes", [])
+    return _STEPS_ADAPTER.validate_python(raw_nodes)
+
+
+def _saved_identity(ref: WorkflowRef) -> tuple[str, int]:
+    """Return the required saved-ref fields after structural model validation."""
+    if ref.artifact_id is None or ref.version is None:
+        raise ValueError(f"workflow ref {ref.display!r} is not a saved artifact ref")
+    return ref.artifact_id, ref.version
+
+
+def _missing_diagnostic(ref: WorkflowRef) -> DependencyDiagnostic:
+    return DependencyDiagnostic(
+        severity=DiagnosticSeverity.ERROR,
+        code="workflow_dependency_missing",
+        logical_ref=ref.display,
+        message=f"Saved child workflow {ref.display!r} is unavailable.",
+        repair_hint=(
+            "Save the referenced artifact version or update the parent graph."
+        ),
+    )
+
+
+def _cycle_diagnostic(ref: WorkflowRef) -> DependencyDiagnostic:
+    return DependencyDiagnostic(
+        severity=DiagnosticSeverity.ERROR,
+        code="workflow_dependency_cycle",
+        logical_ref=ref.display,
+        message=f"Saved child workflow {ref.display!r} creates a dependency cycle.",
+        repair_hint="Remove the recursive saved subgraph reference.",
+    )

tests/core/test_subgraph_step.py

@@ -129,6 +129,35 @@ def test_subgraph_step_executes_prepared_child_in_isolated_scope() -> None:
     assert run.trace[-1].step_type == "subgraph"
 
 
+def test_subgraph_step_executes_caller_prepared_saved_child_ref() -> None:
+    payload = _subgraph_node().model_dump(mode="json")
+    payload["workflow"] = {"artifact_id": "child", "version": 1}
+    workflow = _workflow(
+        node=SubgraphNode.model_validate(payload),
+        output_schema=_schema({"answer": {"type": "string"}}),
+    )
+
+    run = execute_workflow(
+        workflow,
+        {"text": "hello"},
+        {},
+        subgraphs={
+            "workflow.child.v1": PreparedSubgraph(
+                workflow=_child_workflow(),
+                registry={
+                    "answer": lambda child_input, _ctx: {
+                        "answer": f"saved:{child_input['text']}"
+                    }
+                },
+            )
+        },
+    )
+
+    assert run.output["answer"] == "saved:hello"
+    assert run.trace[-1].node_id == "child"
+    assert run.trace[-1].step_type == "subgraph"
+
+
 def test_subgraph_step_executes_prepared_async_child() -> None:
     async def answer(payload: dict[str, object], _ctx: object) -> dict[str, object]:
         return {"answer": f"async:{payload['text']}"}

tests/wf_mcp/test_saved_subgraphs.py

@@ -0,0 +1,312 @@
+from __future__ import annotations
+
+import asyncio
+from typing import Any
+
+from wf_artifacts import (
+    FileWorkflowArtifactStore,
+    RequiredCapability,
+    WorkflowArtifact,
+    WorkflowDeployment,
+)
+from wf_mcp.broker import WfMcpService
+from wf_mcp.models import ConnectionConfig
+from wf_mcp.storage import FileStore
+from wf_mcp.workflow_surface import WorkflowSurfaceHandlers
+from wf_mcp.workflow_surface.saved_subgraphs import resolve_saved_subgraph_tree
+
+from .test_support import echo_tool, input_binding, local_temp_root, output_binding
+
+
+def test_saved_subgraph_tree_loads_exact_child_artifact_version() -> None:
+    store = FileWorkflowArtifactStore(local_temp_root() / "saved_subgraph_tree")
+    parent = _parent_artifact()
+    store.save_artifact(_leaf_artifact())
+
+    resolution = resolve_saved_subgraph_tree(
+        root_artifact=parent,
+        artifact_store=store,
+    )
+
+    assert resolution.diagnostics == []
+    assert resolution.artifacts_by_ref["workflow.child.v1"].id == "child"
+    assert resolution.artifacts_by_ref["workflow.child.v1"].version == 1
+
+
+def test_saved_subgraph_tree_reports_missing_child_artifact() -> None:
+    store = FileWorkflowArtifactStore(local_temp_root() / "saved_subgraph_missing")
+
+    resolution = resolve_saved_subgraph_tree(
+        root_artifact=_parent_artifact(),
+        artifact_store=store,
+    )
+
+    assert len(resolution.diagnostics) == 1
+    assert resolution.diagnostics[0].code == "workflow_dependency_missing"
+    assert resolution.diagnostics[0].logical_ref == "workflow.child.v1"
+
+
+def test_saved_subgraph_tree_reports_recursive_child_cycle() -> None:
+    store = FileWorkflowArtifactStore(local_temp_root() / "saved_subgraph_cycle")
+    parent = _parent_artifact()
+    child = _parent_artifact(
+        artifact_id="child",
+        title="Child",
+        child_artifact_id="parent",
+    )
+    store.save_artifact(parent)
+    store.save_artifact(child)
+
+    resolution = resolve_saved_subgraph_tree(
+        root_artifact=parent,
+        artifact_store=store,
+    )
+
+    assert len(resolution.diagnostics) == 1
+    assert resolution.diagnostics[0].code == "workflow_dependency_cycle"
+    assert resolution.diagnostics[0].logical_ref == "workflow.parent.v1"
+
+
+def test_saved_child_uses_parent_deployment_binding_for_validation() -> None:
+    store = FileWorkflowArtifactStore(local_temp_root() / "saved_subgraph_validate")
+    store.save_artifact(_parent_artifact())
+    store.save_artifact(_leaf_artifact())
+    store.save_deployment(_deployment())
+    handlers = _handlers(store)
+
+    result = asyncio.run(handlers.validate_deployment(deployment_id="parent.personal"))
+
+    assert result["status"] == "runnable"
+    assert result["diagnostics"] == []
+
+
+def test_saved_child_missing_parent_binding_is_unrunnable() -> None:
+    store = FileWorkflowArtifactStore(local_temp_root() / "saved_subgraph_unbound")
+    store.save_artifact(_parent_artifact())
+    store.save_artifact(_leaf_artifact())
+    store.save_deployment(_deployment(bindings={}))
+    handlers = _handlers(store)
+
+    result = asyncio.run(handlers.validate_deployment(deployment_id="parent.personal"))
+
+    assert result["status"] == "unrunnable"
+    assert result["diagnostics"][0]["code"] == "binding_missing"
+    assert result["diagnostics"][0]["logical_ref"] == "demo.echo_tool"
+
+
+def test_interrupting_saved_child_remains_unrunnable_on_deployment_surface() -> None:
+    store = FileWorkflowArtifactStore(local_temp_root() / "saved_subgraph_interrupt")
+    store.save_artifact(_parent_artifact())
+    store.save_artifact(_interrupting_child_artifact())
+    store.save_deployment(_deployment())
+    handlers = _handlers(store)
+
+    result = asyncio.run(handlers.validate_deployment(deployment_id="parent.personal"))
+
+    assert result["status"] == "unrunnable"
+    assert result["diagnostics"][0]["code"] == "interrupting_artifact_unsupported"
+    assert result["diagnostics"][0]["logical_ref"] == "workflow.child.v1"
+
+
+def test_missing_saved_child_is_unrunnable_on_deployment_surface() -> None:
+    store = FileWorkflowArtifactStore(local_temp_root() / "saved_subgraph_missing_run")
+    store.save_artifact(_parent_artifact())
+    store.save_deployment(_deployment())
+    handlers = _handlers(store)
+
+    result = asyncio.run(handlers.validate_deployment(deployment_id="parent.personal"))
+
+    assert result["status"] == "unrunnable"
+    assert result["diagnostics"][0]["code"] == "workflow_dependency_missing"
+    assert result["diagnostics"][0]["logical_ref"] == "workflow.child.v1"
+
+
+def test_cyclic_saved_child_is_unrunnable_on_deployment_surface() -> None:
+    store = FileWorkflowArtifactStore(local_temp_root() / "saved_subgraph_cycle_run")
+    store.save_artifact(_parent_artifact())
+    store.save_artifact(
+        _parent_artifact(
+            artifact_id="child",
+            title="Child",
+            child_artifact_id="parent",
+        )
+    )
+    store.save_deployment(_deployment())
+    handlers = _handlers(store)
+
+    result = asyncio.run(handlers.validate_deployment(deployment_id="parent.personal"))
+
+    assert result["status"] == "unrunnable"
+    assert result["diagnostics"][0]["code"] == "workflow_dependency_cycle"
+    assert result["diagnostics"][0]["logical_ref"] == "workflow.parent.v1"
+
+
+def test_saved_child_runs_natively_with_parent_deployment_binding() -> None:
+    store = FileWorkflowArtifactStore(local_temp_root() / "saved_subgraph_run")
+    store.save_artifact(_parent_artifact())
+    store.save_artifact(_leaf_artifact())
+    store.save_deployment(_deployment())
+    handlers = _handlers(store)
+
+    result = asyncio.run(
+        handlers.run_deployment(
+            deployment_id="parent.personal",
+            workflow_input={"text": "hello"},
+        )
+    )
+
+    assert result["status"] == "completed"
+    assert result["output"]["echoed"] == "hello"
+    assert result["diagnostics"] == []
+
+
+def test_nested_saved_child_inherits_root_deployment_binding() -> None:
+    store = FileWorkflowArtifactStore(local_temp_root() / "saved_subgraph_nested_run")
+    store.save_artifact(_parent_artifact(child_artifact_id="middle"))
+    store.save_artifact(
+        _parent_artifact(
+            artifact_id="middle",
+            title="Middle",
+            child_artifact_id="child",
+        )
+    )
+    store.save_artifact(_leaf_artifact())
+    store.save_deployment(_deployment())
+    handlers = _handlers(store)
+
+    result = asyncio.run(
+        handlers.run_deployment(
+            deployment_id="parent.personal",
+            workflow_input={"text": "hello"},
+        )
+    )
+
+    assert result["status"] == "completed"
+    assert result["output"]["echoed"] == "hello"
+    assert result["diagnostics"] == []
+
+
+def _leaf_artifact() -> WorkflowArtifact:
+    plan: dict[str, Any] = {
+        "name": "child",
+        "input_schema": _io_schema("text"),
+        "state_schema": {"fields": {"echoed": {"type": "string"}}},
+        "output_schema": _io_schema("echoed"),
+        "start": "echo",
+        "nodes": [
+            {
+                "id": "echo",
+                "type": "node",
+                "node": "demo.echo_tool",
+                "input": [input_binding("input.text", "text")],
+                "output": [output_binding("echoed", "state.echoed")],
+            }
+        ],
+        "edges": [{"from": "echo", "outcome": "ok", "to": "__end__"}],
+    }
+    return WorkflowArtifact(
+        id="child",
+        version=1,
+        title="Child",
+        input_schema=plan["input_schema"],
+        output_schema=plan["output_schema"],
+        outcomes=("completed",),
+        plan=plan,
+        required_capabilities=[
+            RequiredCapability(ref="demo.echo_tool", kind="node_spec")
+        ],
+    )
+
+
+def _parent_artifact(
+    *,
+    artifact_id: str = "parent",
+    title: str = "Parent",
+    child_artifact_id: str = "child",
+) -> WorkflowArtifact:
+    plan: dict[str, Any] = {
+        "name": artifact_id,
+        "input_schema": _io_schema("text"),
+        "state_schema": {"fields": {"echoed": {"type": "string"}}},
+        "output_schema": _io_schema("echoed"),
+        "start": "child_step",
+        "nodes": [
+            {
+                "id": "child_step",
+                "type": "subgraph",
+                "workflow": {"artifact_id": child_artifact_id, "version": 1},
+                "input_schema": _io_schema("text"),
+                "output_schema": _io_schema("echoed"),
+                "input": [input_binding("input.text", "text")],
+                "output": [output_binding("echoed", "state.echoed")],
+            }
+        ],
+        "edges": [{"from": "child_step", "outcome": "ok", "to": "__end__"}],
+    }
+    return WorkflowArtifact(
+        id=artifact_id,
+        version=1,
+        title=title,
+        input_schema=plan["input_schema"],
+        output_schema=plan["output_schema"],
+        outcomes=("completed",),
+        plan=plan,
+    )
+
+
+def _io_schema(field: str) -> dict[str, Any]:
+    return {
+        "type": "object",
+        "properties": {field: {"type": "string"}},
+        "required": [field],
+    }
+
+
+def _interrupting_child_artifact() -> WorkflowArtifact:
+    plan: dict[str, Any] = {
+        "name": "child",
+        "input_schema": _io_schema("text"),
+        "state_schema": {"fields": {"echoed": {"type": "string"}}},
+        "output_schema": _io_schema("echoed"),
+        "start": "ask",
+        "nodes": [
+            {
+                "id": "ask",
+                "type": "interrupt",
+                "kind": "input",
+                "request": [input_binding("input.text", "question")],
+                "resume": [output_binding("answer", "state.echoed")],
+            }
+        ],
+        "edges": [{"from": "ask", "outcome": "submitted", "to": "__end__"}],
+    }
+    return WorkflowArtifact(
+        id="child",
+        version=1,
+        title="Interrupting Child",
+        input_schema=plan["input_schema"],
+        output_schema=plan["output_schema"],
+        outcomes=("completed",),
+        plan=plan,
+    )
+
+
+def _deployment(*, bindings: dict[str, str] | None = None) -> WorkflowDeployment:
+    return WorkflowDeployment(
+        id="parent.personal",
+        artifact_id="parent",
+        artifact_version=1,
+        bindings={"demo": "demo.personal"} if bindings is None else bindings,
+    )
+
+
+def _handlers(artifact_store: FileWorkflowArtifactStore) -> WorkflowSurfaceHandlers:
+    service = WfMcpService(
+        store=FileStore(local_temp_root() / f"{artifact_store.root.name}_mcp"),
+        artifact_store=artifact_store,
+    )
+    service.register_connection(
+        ConnectionConfig(id="demo.personal", server="demo", account="personal")
+    )
+    service.register_specs("demo.personal", echo_tool)
+    return WorkflowSurfaceHandlers(service)