feat: add structured foreach back-edge execution

foreach back-edge execution and control-region validation

docs/current_roadmap.md

@@ -795,12 +795,6 @@ stable.
 
 - Native subgraph polish: optional per-use-site child deployment overrides and
   clearer child trace inspection.
-- Active concurrent foreach correction: replace item-body `END` routes with
-  canonical back-edges to the owning foreach. The approved semantics are in the
-  [`foreach back-edge design`](superpowers/specs/2026-09-04-foreach-back-edge-design.md).
-  This slice also makes foreach control regions fail-closed, rejects unreachable
-  workflow nodes, and gives repeated visits to one foreach node distinct
-  persisted activation identities.
 - Proposed follow-up: replace innermost-only foreach values with same-scope
   [`structured runtime context`](superpowers/specs/2026-09-04-structured-runtime-context-design.md),
   including typed Python lookup, graph paths, schema analysis, authoring refs,
@@ -808,7 +802,7 @@ stable.
 - Proposed runtime guard: add a persisted, run-wide
   [`step budget`](superpowers/specs/2026-09-04-run-step-budget-design.md) for
   valid graph cycles that cannot be proven terminating during validation.
-- After that correction, reuse the foreach barrier/lineage machinery for
+- Next, reuse the foreach barrier/lineage machinery for
   fork/gather. The proposed control semantics are recorded in
   [`ADR-0006`](adr/0006-explicit-fork-and-topology-driven-gather.md).
 - Protocol-native progress: investigate MCP tasks/progress or WebSocket/SSE only
@@ -949,6 +943,11 @@ stable.
   routes, or outputs. Python, JSON-RPC, MCP, and local/remote CLI surfaces are
   aligned. Implementation plan:
   [`capability step updates`](historical/superpowers/plans/2026-07-26-capability-step-update.md).
+- Completed: foreach bodies now return through validated back-edges to their
+  immediate owner, with unique static control regions and fresh persisted
+  activation identities for every dynamic visit. Design:
+  [`foreach back-edge design`](superpowers/specs/2026-09-04-foreach-back-edge-design.md).
+  Fork/gather remains explicitly deferred.
 
 Agent evaluation cohort status and policy:
 

docs/historical/superpowers/plans/2026-09-04-foreach-back-edges.md

@@ -3,7 +3,7 @@
 > **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.
+> checkbox (`- [x]`) syntax for tracking.
 
 **Goal:** Make foreach bodies return through validated back-edges to their
 immediate owner, with unique static control regions and fresh persisted state
@@ -19,7 +19,7 @@ back-edge as item completion.
 pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
 
 **Spec:**
-[`docs/superpowers/specs/2026-09-04-foreach-back-edge-design.md`](../specs/2026-09-04-foreach-back-edge-design.md)
+[`docs/superpowers/specs/2026-09-04-foreach-back-edge-design.md`](../../../superpowers/specs/2026-09-04-foreach-back-edge-design.md)
 
 ## Global Constraints
 
@@ -85,7 +85,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
 - `owner_stack_by_node` contains only nodes whose region is unambiguous. Later
   context analysis must not grant foreach fields to a conflicted node.
 
-- [ ] **Step 1: Write failing acceptance tests for legal regions**
+- [x] **Step 1: Write failing acceptance tests for legal regions**
 
   Add explicit tests named:
 
@@ -108,7 +108,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
   assert analysis.issues == ()
   ```
 
-- [ ] **Step 2: Run legal-region tests and confirm the missing module fails**
+- [x] **Step 2: Run legal-region tests and confirm the missing module fails**
 
   Run:
 
@@ -119,7 +119,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
   Expected: collection fails because `wf_core.analysis.control_regions` does
   not exist.
 
-- [ ] **Step 3: Implement semantic traversal over node and owner stack**
+- [x] **Step 3: Implement semantic traversal over node and owner stack**
 
   Use a bounded worklist of `(node_id, owner_stack)` states. The special edge
   handling must follow this order:
@@ -149,7 +149,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
   Ignore unknown sources and targets here because ordinary edge validation
   already owns those diagnostics.
 
-- [ ] **Step 4: Write failing tests for every invalid pressure case**
+- [x] **Step 4: Write failing tests for every invalid pressure case**
 
   Add one explicit test per topology:
 
@@ -172,7 +172,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
   )
   ```
 
-- [ ] **Step 5: Implement conflicts, reachability, and returnability**
+- [x] **Step 5: Implement conflicts, reachability, and returnability**
 
   Record the first stack for each node. If a second distinct stack reaches the
   same node, remove it from `owner_stack_by_node` and emit one region conflict.
@@ -185,7 +185,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
   Suppress cascading no-return diagnostics when a region conflict, invalid
   return, invalid terminal, or empty body already makes that state ambiguous.
 
-- [ ] **Step 6: Run analyzer tests**
+- [x] **Step 6: Run analyzer tests**
 
   Run:
 
@@ -198,7 +198,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
 
   Expected: all commands pass.
 
-- [ ] **Step 7: Commit the analyzer**
+- [x] **Step 7: Commit the analyzer**
 
   ```bash
   git add src/wf_core/analysis/control_regions.py \
@@ -223,7 +223,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
   `loop_item`, `loop_index`, and its alias; completing it restores the outer
   context. It does not expose all enclosing aliases.
 
-- [ ] **Step 1: Rewrite context tests to canonical back-edges**
+- [x] **Step 1: Rewrite context tests to canonical back-edges**
 
   Replace successful item routes such as:
 
@@ -244,7 +244,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
   {"from": "after_inner", "outcome": "ok", "to": "outer"}
   ```
 
-- [ ] **Step 2: Replace the mixed-reachability expectation**
+- [x] **Step 2: Replace the mixed-reachability expectation**
 
   Delete the test that expects one node to receive conditional loop fields when
   reached both inside and outside a foreach. Add a test proving conflicted nodes
@@ -260,7 +260,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
   assert "inner_item" not in after_inner
   ```
 
-- [ ] **Step 3: Run the context tests and confirm old traversal fails**
+- [x] **Step 3: Run the context tests and confirm old traversal fails**
 
   Run:
 
@@ -271,7 +271,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
   Expected: failures show that the single `FrameScope` traversal neither pops
   canonical return edges nor consumes region-conflict diagnostics.
 
-- [ ] **Step 4: Replace duplicate traversal with the analyzer result**
+- [x] **Step 4: Replace duplicate traversal with the analyzer result**
 
   Remove the local breadth-first scope traversal. For each unambiguous node,
   derive its active context from the final stack item:
@@ -286,7 +286,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
   diagnostics to bounded context warnings. Do not reintroduce multiple scopes
   or conditional fields for a single node use.
 
-- [ ] **Step 5: Run context and authoring-contract tests**
+- [x] **Step 5: Run context and authoring-contract tests**
 
   Run:
 
@@ -300,7 +300,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
 
   Expected: all commands pass.
 
-- [ ] **Step 6: Commit context integration**
+- [x] **Step 6: Commit context integration**
 
   ```bash
   git add src/wf_core/analysis/context_scopes.py \
@@ -360,7 +360,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
 - Callers compare owner fields by name; remove tuple slicing and positional
   unpacking.
 
-- [ ] **Step 1: Write failing activation-lifecycle tests**
+- [x] **Step 1: Write failing activation-lifecycle tests**
 
   Add tests proving:
 
@@ -379,7 +379,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
   Also test malformed metadata, mode mismatch, closing a stale activation, and
   JSON round-trip through `ExecutionFrame.metadata`.
 
-- [ ] **Step 2: Run activation tests and confirm failure**
+- [x] **Step 2: Run activation tests and confirm failure**
 
   Run:
 
@@ -389,7 +389,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
 
   Expected: imports fail because activation lifecycle helpers do not exist.
 
-- [ ] **Step 3: Implement the activation metadata seam**
+- [x] **Step 3: Implement the activation metadata seam**
 
   Hide the JSON dictionary shape inside `foreach_state.py`. Persist, per parent
   frame and foreach node id, a monotonically increasing visit sequence plus at
@@ -400,7 +400,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
   retain a compatibility reader for the old barrier-only shape because the spec
   found no real persisted foreach data.
 
-- [ ] **Step 4: Add activation identity to item metadata and helpers**
+- [x] **Step 4: Add activation identity to item metadata and helpers**
 
   Require this shape:
 
@@ -417,14 +417,14 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
   Child frame and lineage ids must include `activation.id`, so a later visit at
   item index zero cannot collide with the first visit.
 
-- [ ] **Step 5: Move runtime callers onto named owner and activation state**
+- [x] **Step 5: Move runtime callers onto named owner and activation state**
 
   Update lineage reads, node-result buffering, async batching, failure
   collection, refill, and barrier commit to load the activation named by the
   child. Fail closed when a child result names a closed or different active
   activation.
 
-- [ ] **Step 6: Update focused metadata tests**
+- [x] **Step 6: Update focused metadata tests**
 
   Replace hand-written item metadata in `test_foreach_barrier_state.py` and
   `test_scheduler.py` with required activation ids. Update hard-coded child
@@ -432,7 +432,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
   include the activation identity. Assert `item_frame_owner` returns
   `ForeachItemOwner`, not a tuple.
 
-- [ ] **Step 7: Run runtime-state tests**
+- [x] **Step 7: Run runtime-state tests**
 
   Run:
 
@@ -449,7 +449,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
 
   Expected: all commands pass.
 
-- [ ] **Step 8: Commit activation identity**
+- [x] **Step 8: Commit activation identity**
 
   ```bash
   git add src/wf_core/runtime/foreach_state.py \
@@ -488,7 +488,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
 - Produces an internal helper that derives ancestor foreach owners from frame
   ancestry for defensive non-local-return rejection.
 
-- [ ] **Step 1: Write failing serial return tests**
+- [x] **Step 1: Write failing serial return tests**
 
   Add tests with canonical edges:
 
@@ -501,7 +501,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
   Prove two items execute, the child finishes at `each`, the parent wakes, and
   the final workflow outcome remains `ok`.
 
-- [ ] **Step 2: Write failing cycle, nested, and re-entry runtime tests**
+- [x] **Step 2: Write failing cycle, nested, and re-entry runtime tests**
 
   Add explicit tests named:
 
@@ -518,7 +518,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
   direct defensive test constructs an invalid frame chain without running
   workflow preparation and asserts `WorkflowExecutionError`.
 
-- [ ] **Step 3: Implement immediate-owner return in frame advancement**
+- [x] **Step 3: Implement immediate-owner return in frame advancement**
 
   Before `END` handling or ordinary enqueue:
 
@@ -540,20 +540,20 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
   an item targets `END`, or targets a foreach found below its immediate owner in
   the active ancestor chain, raise `WorkflowExecutionError` defensively.
 
-- [ ] **Step 4: Close activations before controller completion edges**
+- [x] **Step 4: Close activations before controller completion edges**
 
   In both serial and concurrent completion paths, close the active activation
   before calling `advance_frame` for `done` or `completed_with_errors`. This
   makes a self-looping or later returning completion edge start a fresh visit.
 
-- [ ] **Step 5: Migrate executable foreach fixtures**
+- [x] **Step 5: Migrate executable foreach fixtures**
 
   Change item-success routes from `END` to their owner in every file listed for
   this task. Keep controller completion routes to `END` or their real outer
   continuation. For nested fixtures, return inner bodies to the inner foreach
   and outer-tail nodes to the outer foreach.
 
-- [ ] **Step 6: Prove concurrent, async, error, and interrupt behavior**
+- [x] **Step 6: Prove concurrent, async, error, and interrupt behavior**
 
   Run:
 
@@ -572,7 +572,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
   fail-closed test showing a completed activation cannot accept a result or
   wake-up from another activation.
 
-- [ ] **Step 7: Run runtime static checks**
+- [x] **Step 7: Run runtime static checks**
 
   Run:
 
@@ -588,7 +588,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
 
   Expected: all commands pass.
 
-- [ ] **Step 8: Commit runtime back-edges**
+- [x] **Step 8: Commit runtime back-edges**
 
   ```bash
   git add src/wf_core/runtime/ops/flow.py \
@@ -624,7 +624,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
 - Keeps `Workflow.validate_structure()` and `ValidationReport` signatures
   unchanged.
 
-- [ ] **Step 1: Add failing public-validation assertions**
+- [x] **Step 1: Add failing public-validation assertions**
 
   For every pressure-case test, call both the pure analyzer and
   `workflow.validate_structure()`. Invalid cases must assert the public code and
@@ -642,7 +642,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
   Legal cases assert `report.ok`. Add a test proving every unreachable node in
   one component receives its own `UNREACHABLE_NODE` issue.
 
-- [ ] **Step 2: Run public-validation tests and confirm failure**
+- [x] **Step 2: Run public-validation tests and confirm failure**
 
   Run:
 
@@ -652,7 +652,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
 
   Expected: analyzer tests pass, but public reports lack the new issue codes.
 
-- [ ] **Step 3: Wire analysis into validation once**
+- [x] **Step 3: Wire analysis into validation once**
 
   Add enum members with exactly the analyzer values. Call
   `analyze_control_regions(workflow)` after ordinary node and edge validation,
@@ -668,7 +668,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
 
   Do not add a second graph traversal inside validation.
 
-- [ ] **Step 4: Canonicalize policy and draft fixtures**
+- [x] **Step 4: Canonicalize policy and draft fixtures**
 
   Policy-only workflow helpers must include a distinct body node and route it
   back to the foreach owner. Draft fixtures with:
@@ -688,7 +688,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
   Parse-only policy fixtures still use a distinct body; do not preserve an
   invalid `loop -> __end__` shortcut just because the test does not execute it.
 
-- [ ] **Step 5: Run validation and draft suites**
+- [x] **Step 5: Run validation and draft suites**
 
   Run:
 
@@ -703,7 +703,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
   `UNREACHABLE_NODE` when disconnection is the behavior under test. Do not add
   an allow-unreachable flag.
 
-- [ ] **Step 6: Run core validation static checks**
+- [x] **Step 6: Run core validation static checks**
 
   Run:
 
@@ -717,7 +717,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
 
   Expected: all commands pass.
 
-- [ ] **Step 7: Commit fail-closed validation**
+- [x] **Step 7: Commit fail-closed validation**
 
   ```bash
   git add src/wf_core/validation tests/core/test_foreach_control_regions.py \
@@ -744,7 +744,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
   surface.
 - Preserves historical reports and recorded agent-challenge outputs verbatim.
 
-- [ ] **Step 1: Search for stale canonical foreach returns**
+- [x] **Step 1: Search for stale canonical foreach returns**
 
   Run targeted searches:
 
@@ -760,7 +760,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
   completion changes to the owner. Do not rewrite unrelated ordinary terminal
   routes or immutable historical evidence.
 
-- [ ] **Step 2: Update live architecture and authoring docs**
+- [x] **Step 2: Update live architecture and authoring docs**
 
   Replace the old architecture statement that item children reach `END` with:
 
@@ -781,13 +781,13 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
   Document that region conflicts, unreachable nodes, body terminals, non-local
   returns, empty bodies, and bodies without possible returns fail validation.
 
-- [ ] **Step 3: Mark the design implemented and roadmap item complete**
+- [x] **Step 3: Mark the design implemented and roadmap item complete**
 
   Set the spec status to `Implemented on 2026-09-04`. Move the roadmap bullet
   from active correction to recently completed runtime work. Keep fork/gather
   explicitly deferred.
 
-- [ ] **Step 4: Run the focused acceptance matrix**
+- [x] **Step 4: Run the focused acceptance matrix**
 
   Run:
 
@@ -806,7 +806,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
   Expected: every current pressure-case row passes. The future-fork row remains
   documented and unimplemented because no fork node exists.
 
-- [ ] **Step 5: Run repository verification**
+- [x] **Step 5: Run repository verification**
 
   Run:
 
@@ -826,7 +826,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
   unrelated lint debt, do not run an unsafe global auto-fix; report it and keep
   this slice's edited documents clean.
 
-- [ ] **Step 6: Commit implementation documentation**
+- [x] **Step 6: Commit implementation documentation**
 
   ```bash
   git add docs/wf_core_architecture.md docs/wf_authoring_control_flow.md \
@@ -835,7 +835,7 @@ pytest, pytest-asyncio, Ruff, basedpyright, markdownlint-cli2.
   git commit -m "docs: publish foreach back-edge semantics"
   ```
 
-- [ ] **Step 7: Archive the completed plan**
+- [x] **Step 7: Archive the completed plan**
 
   After every prior task is complete and committed:
 

docs/superpowers/specs/2026-09-04-foreach-back-edge-design.md

@@ -2,9 +2,9 @@
 
 ## Status
 
-Approved in conversation on 2026-09-04. This document specifies canonical
-foreach body-return semantics. It does not include the separately planned
-ergonomic Python DSL or authorize fork/gather implementation.
+Implemented on 2026-09-04. This document specifies canonical foreach
+body-return semantics. It does not include the separately planned ergonomic
+Python DSL or authorize fork/gather implementation.
 
 ## Purpose
 
@@ -203,9 +203,10 @@ foreach_owner_stack)` rather than merely looking for graph cycles:
 A node use therefore belongs to one static control region, while remaining free
 to execute in any number of dynamic frames, lineages, or items. When the same
 capability is needed at two program locations, authoring creates two node uses
-with distinct identifiers. Existing context-contract analysis may still report
-fields as conditional because multiple paths can reach a node within its one
-region; it must not use multiple owner stacks to represent that case.
+with distinct identifiers. Context-contract analysis reports one field set per
+static region: fields are available when the region is inside a foreach body
+and absent outside it. A node reached under two stacks is a region conflict
+and receives no foreach fields rather than a conditional union.
 
 The unique-owner rule rejects both ways of crossing a foreach boundary. An
 outside edge into a body node reaches that node under both the outer and item
@@ -431,9 +432,24 @@ may independently return and complete the item.
 ## State and Failure Behavior
 
 Back-edge return changes control representation, not state semantics.
-Iteration writes remain buffered in the item lineage. Serial behavior and the
-concurrent barrier continue to commit or merge those writes according to the
-accepted concurrent-foreach ADR and declared reducers.
+Concurrent iteration writes remain buffered in the item lineage for the
+barrier to merge, while serial owners pass writes outward to the scope
+root, which commits them according to the accepted concurrent-foreach ADR
+and declared reducers. One shared helper
+routes every item write: it climbs through each serial owner to the scope
+root, where it commits, or selects the first concurrent boundary as the
+buffer target, where it buffers for that barrier to merge (the walk
+continues past the selected boundary to validate the full ancestry, so
+parent cycles fail closed even when they pass through a concurrent
+owner; the concurrent barrier finish
+routes its combined patch through the same helper, so nested serial owners
+cannot strand it). Parent cycles, missing parents, and orphaned item frames
+fail closed. Buffered failure records must carry an error whose index and
+frame match the enclosing result. The completed item is
+registered with its barrier at the owner back-edge, keyed by the returning
+frame rather than by whichever operation ran last, so node, subgraph, and
+nested-control endings all count. A return naming a closed or superseded
+activation fails closed instead of buffering into the wrong visit.
 
 An ordinary node outcome named `error` remains domain control. An exception
 remains a runtime item failure handled by `fail`, `skip`, or `collect`. Neither
@@ -490,7 +506,7 @@ semantics also run through the runtime.
 | Closed body cycle | Reject missing owner return | N/A |
 | Unreachable nodes | Reject each node | N/A |
 | Re-enter foreach after `done` | Accept | Fresh activation and children |
-| Subgraph inside foreach | Accept | Child `END`, then item return |
+| Subgraph inside foreach | Accept | Child `END`, then item return (serial and concurrent) |
 | Interrupt inside foreach | Accept | Resume the same item activation |
 | Future fork in foreach | Deferred with fork/gather | Gather before return |
 

docs/wf_authoring_control_flow.md

@@ -228,6 +228,17 @@ step with item-local child lineages:
 In async execution, admitted async item node handlers may run at the same time.
 Run-state mutation, tracing, and barrier commits remain deterministic.
 
+An iteration body returns through its immediate owning foreach:
+
+```python
+g.connect(each, "loop", record)
+g.connect(record, "ok", each)
+g.connect(each, "done", END)
+```
+
+Region conflicts, unreachable nodes, body terminals, non-local returns, empty
+bodies, and bodies without possible returns fail validation.
+
 See `examples/authoring_concurrent_foreach.py` for a runnable example covering:
 
 - sync concurrent foreach with `item_error={"action": "collect", ...}`;

docs/wf_core_architecture.md

@@ -74,9 +74,10 @@ interrupted, failed, or deadlocked. This replaces the older assumption that
 ## Foreach
 
 Serial foreach creates one iteration child frame, records typed
-`ForeachIterationMetadata`, blocks on that child, and enqueues the child. When
-the child reaches `END`, `wake_parent_if_children_complete` wakes the blocked
-parent so it can create the next iteration or emit `done`.
+`ForeachIterationMetadata`, blocks on that child, and enqueues the child. An
+item child returns by targeting its immediate owning foreach. The child
+finishes at that owner location without executing the controller; the parent
+activation consumes the result and continues or completes its barrier.
 
 Concurrent foreach uses the same frame machinery but admits multiple item
 lineages according to `ForeachConcurrentPolicy`. Each item lineage reads through
@@ -98,6 +99,9 @@ See `examples/raw_concurrent_foreach.py` for the canonical raw workflow shape an
 - validate edge sources, destinations, duplicate outcomes, and declared outcomes
 - validate reachable nodes have all required outcome edges
 - validate explicit `EndNode` outcomes against `Workflow.outcomes`
+- validate foreach control regions once: region conflicts, unreachable nodes,
+  body terminals, non-local returns, empty bodies, and bodies without possible
+  returns fail validation
 
 Validation reports multiple issues through `ValidationReport` instead of
 raising at the first failure.