fix(todos): settle durable Next Action on completion

loopx/bootstrap.py

@@ -7,15 +7,16 @@
 from typing import Any
 
 from .control_plane.runtime.time import now_local_iso
-from .control_plane.todos.handoff_mode import (
-    HANDOFF_MODE_LEGACY,
-    goal_handoff_mode,
-)
 from .control_plane.todos.active_state_editing import (
     TODO_SECTION_HEADINGS,
     insertion_anchor,
     section_bounds,
 )
+from .control_plane.todos.next_action_runtime import bind_next_action_to_todo
+from .control_plane.todos.handoff_mode import (
+    HANDOFF_MODE_LEGACY,
+    goal_handoff_mode,
+)
 from .execution_profile import (
     build_execution_profile,
     compact_execution_profile,
@@ -376,14 +377,15 @@ def apply_onboarding_todos_to_state(
             else None
         )
         if action:
-            add_todo_to_lines(
+            added = add_todo_to_lines(
                 lines,
                 role="agent",
                 text=action["text"],
                 task_class=action["task_class"],
                 action_kind=action["action_kind"],
                 updated_at=updated_at,
             )
+            bind_next_action_to_todo(lines, todo_id=str(added["todo_id"]))
         return "\n".join(lines) + "\n"
     lines = text.splitlines()
     if accept_onboarding_agent_todos:

loopx/control_plane/effect_runtime.py

@@ -31,6 +31,7 @@
     "effect_runtime_handlers.ts",
     "effect_runtime_io.ts",
     "effect_runtime_server.ts",
+    "todos/next_action.ts",
     "turn_driver/turn_journal.ts",
     "turn_driver/turn_journal_effects.ts",
     "turn_transaction_contract.json",

loopx/control_plane/effect_runtime_handlers.ts

@@ -33,6 +33,7 @@ import {
   type TurnJournalInspectionRequest,
 } from "./turn_driver/turn_journal.ts";
 import { commitTurnJournal } from "./turn_driver/turn_journal_effects.ts";
+import { transitionTodoNextAction } from "./todos/next_action.ts";
 
 type EffectRuntimeHandler = (params: JsonObject) => unknown | Promise<unknown>;
 
@@ -261,6 +262,7 @@ export function createEffectRuntimeHandlers(
       (params) => interpretTurnJournal(turnJournalInspectionRequest(params)),
     ],
     ["turn_journal.write", commitTurnJournal],
+    ["todo.next_action.transition", transitionTodoNextAction],
     [
       "effect.program_from_ordered_steps",
       (params) => effectProgramFromOrderedSteps(

loopx/control_plane/todos/line_update.py

@@ -112,6 +112,49 @@ def link_generated_successor_todo_ids(
     return metadata_updated
 
 
+def link_superseding_todo_id(
+    lines: list[str],
+    *,
+    update_result: dict[str, Any],
+    role: str | None,
+    successor_todo_ids: list[str],
+) -> bool:
+    """Persist supersede lineage after generated successors are materialized."""
+
+    if not successor_todo_ids:
+        return False
+    block_match = find_todo_block(
+        lines,
+        todo_id=str(update_result.get("todo_id") or ""),
+        role=role,
+    )
+    if not block_match:
+        return False
+    _resolved_role, _section, _start, _end, block = block_match
+    merged_successor_ids = merge_todo_id_lists(
+        update_result.get("successor_todo_ids"),
+        successor_todo_ids,
+    )
+    metadata_updated = upsert_todo_metadata(
+        lines,
+        block,
+        metadata_line_for_todo_block(
+            block,
+            {
+                "superseded_by": successor_todo_ids[0],
+                "successor_todo_ids": merged_successor_ids,
+            },
+        ),
+    )
+    update_result["metadata_updated"] = bool(
+        update_result.get("metadata_updated") or metadata_updated
+    )
+    update_result["superseded_by"] = successor_todo_ids[0]
+    update_result["successor_todo_ids"] = merged_successor_ids
+    update_result["changed"] = True
+    return metadata_updated
+
+
 def apply_todo_update_to_lines(
     lines: list[str],
     *,