checkpoint

⚒️ Generated with [Fabro](https://fabro.sh)

stages/004-preflight_lint@1/output.log

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stages/004-preflight_lint@1/script_timing.json

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stages/004-preflight_lint@1/status.json

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+{
+  "outcome": "succeeded",
+  "notes": "Script completed: cargo +nightly-2026-04-14 clippy -q --workspace --all-targets -- -D warnings 2>&1",
+  "failure_reason": null,
+  "timestamp": "2026-05-24T13:38:21.217585Z"
+}

stages/005-implement@1/prompt.md

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+Goal: ---
+title: fix: Prefer root stage TODO projection
+type: fix
+status: active
+date: 2026-05-24
+---
+
+# fix: Prefer Root Stage TODO Projection
+
+## Overview
+
+Fix stage TODO projection so `StageProjection.todos` represents the selected
+stage agent's root session plan. Today a child OpenAI session can emit its own
+`todo.created` events on the same `stage_id`, replacing the root list and
+causing later root `todo.updated` completions to be ignored. The visible
+symptom is an agent sidebar showing a stale child TODO list such as `0/3`
+completed even though the root stage plan completed.
+
+## Problem Frame
+
+OpenAI `update_plan` lists are scoped per agent session as
+`openai_plan:<session_id>`. A stage may contain both the root agent session and
+child/subagent sessions. `StageProjection` currently has only one
+`todos: Option<TodoListProjection>`, so the reducer must choose which list is
+the stage-level list. The stage sidebar is a stage-agent summary, so it should
+show the root stage session's list rather than whichever session most recently
+created todos.
+
+## Requirements Trace
+
+- R1. Root OpenAI plan TODOs must remain the projected `stage.todos` list even
+  when child OpenAI sessions emit TODO events on the same stage.
+- R2. Later root OpenAI `todo.updated` and `todo.deleted` events must continue
+  to apply after child OpenAI TODO events are observed.
+- R3. Child OpenAI TODO lists must not create, replace, or mutate
+  `StageProjection.todos`.
+- R4. Anthropic task projection must remain unchanged because Anthropic task
+  lists are intentionally scoped to the root session and shared across
+  subagents.
+- R5. Do not change public API shapes, generated API types, or frontend
+  rendering code for this fix.
+
+## Scope Boundaries
+
+- Do not add a multi-list TODO projection in this change.
+- Do not expose child/subagent TODO lists in the sidebar in this change.
+- Do not change `TodoListProjection`, `StageProjection`, or OpenAPI schemas.
+- Do not change event serialization, event names, or the agent `update_plan`
+  tool behavior.
+
+## Context & Research
+
+### Relevant Code and Patterns
+
+- `lib/crates/fabro-agent/src/todo_tools.rs` scopes OpenAI plans by
+  `session_id`, producing `openai_plan:<session_id>`.
+- `lib/crates/fabro-types/src/run_event/mod.rs` already carries
+  `session_id` and `parent_session_id` on event envelopes.
+- `lib/crates/fabro-store/src/run_state.rs` owns the persisted-event reducer
+  that updates `StageProjection.todos` from `todo.created`, `todo.updated`,
+  and `todo.deleted`.
+- The existing `todo_reducer` test module in `run_state.rs` is the right place
+  for focused regression coverage.
+- `apps/fabro-web/app/routes/run-stages.tsx` and
+  `apps/fabro-web/app/components/stage-insights-sidebar.tsx` already render
+  `stage.todos`; no UI change is needed if the projection is corrected.
+
+### Observed Failing Case
+
+For run `01KSBT48J14ZMK9HQN48SVMG3T`, stage `simplify_gpt@1` had:
+
+- Root list `openai_plan:2f4458b9-1128-4a96-8dfa-bff4b73b9c33`: five root
+  todos, all completed by later `todo.updated` events.
+- Child list `openai_plan:a09b9432-823d-4068-91fa-5c6185578e8e`: three child
+  todos, created with `parent_session_id` set and never updated.
+
+The child `todo.created` events replaced `stage.todos`, so the sidebar showed
+the child list as `0/3` even after the root list completed.
+
+## Key Technical Decisions
+
+- Use `parent_session_id` as the root-vs-child signal for OpenAI plan
+  projection. A root stage session has `parent_session_id == None`; child
+  sessions have `parent_session_id != None`.
+- Ignore child OpenAI plan events for `StageProjection.todos`. This preserves
+  the current single-list schema while making the selected list match the
+  stage sidebar's meaning.
+- Keep Anthropic task projection unchanged. Anthropic tasks use
+  `anthropic_tasks:<root_session_id>`, so child-session envelopes should still
+  be allowed to update the shared root task list.
+- Treat legacy OpenAI events without `parent_session_id` as root-compatible for
+  backwards compatibility.
+
+## Implementation Units
+
+- [ ] **Unit 1: Add reducer policy for projectable stage TODO events**
+
+**Goal:** Make the reducer distinguish root OpenAI plan events from child
+OpenAI plan events before mutating `stage.todos`.
+
+**Files:**
+- Modify: `lib/crates/fabro-store/src/run_state.rs`
+
+**Approach:**
+- Add a small helper near the TODO reducer functions, for example
+  `should_project_stage_todo_event(stored: &RunEvent, list_kind:
+  TodoListKind) -> bool`.
+- Return `false` only when `list_kind == TodoListKind::OpenAiPlan` and
+  `stored.parent_session_id.is_some()`.
+- Return `true` for root OpenAI events and all Anthropic task events.
+- Call this helper in the `EventBody::TodoCreated`,
+  `EventBody::TodoUpdated`, and `EventBody::TodoDeleted` match arms before
+  resolving or mutating the stage projection.
+- Leave `apply_todo_created`, `apply_todo_updated`, and
+  `apply_todo_deleted` focused on list mutation once the caller has decided
+  the event is projectable.
+
+**Test scenarios:**
+- Root OpenAI events with no `parent_session_id` still create and update
+  `stage.todos`.
+- Child OpenAI events with `parent_session_id` do not create `stage.todos`
+  when no root list exists.
+- Child OpenAI events do not replace an existing root OpenAI list.
+- Root OpenAI updates still apply after ignored child OpenAI events.
+
+- [ ] **Unit 2: Add focused reducer regression tests**
+
+**Goal:** Lock the intended root-list behavior so future TODO projection work
+does not regress the sidebar.
+
+**Files:**
+- Modify: `lib/crates/fabro-store/src/run_state.rs`
+
+**Approach:**
+- Extend the existing `todo_reducer` module rather than creating a new test
+  file.
+- Add a test helper or local event setup that sets
+  `event.event.parent_session_id = Some(parent_session_id.to_string())` for
+  child-session events.
+- Add one regression test that reproduces the failing sequence:
+  root OpenAI creates list, child OpenAI creates a different list on the same
+  stage, root OpenAI completes its items. Assert the final projection is the
+  root list and all root statuses are completed.
+- Add one test proving child OpenAI events alone do not create a stage TODO
+  projection.
+- Add one test proving Anthropic child-session task events still project.
+
+**Verification:**
+- `cargo nextest run -p fabro-store todo_reducer`
+- `cargo +nightly-2026-04-14 fmt --check --all`
+
+## System-Wide Impact
+
+- **API compatibility:** No response schema changes. Existing consumers of
+  `StageProjection.todos` continue to receive a single list.
+- **UI behavior:** The sidebar should show the root agent's TODO progress for
+  the selected stage. Child OpenAI session plans remain available only in the
+  raw event stream for now.
+- **Historical runs:** Replaying existing event logs should produce corrected
+  projections because the decision uses envelope fields already persisted on
+  child events.
+- **Future extensibility:** If child/subagent TODO display is needed later,
+  add a multi-list projection separately rather than overloading
+  `stage.todos`.
+
+## Risks & Mitigations
+
+| Risk | Mitigation |
+|------|------------|
+| Some legacy child OpenAI events lack `parent_session_id` and still project as root | Accept this for backwards compatibility; only events with explicit child-session evidence are filtered. |
+| Anthropic child task updates could be accidentally filtered | Gate only `TodoListKind::OpenAiPlan`; add a regression test for `TodoListKind::AnthropicTasks`. |
+| Root list replacement semantics become ambiguous if a root stage emits multiple OpenAI list IDs | Preserve current root replacement behavior; the fix only prevents child lists from replacing root lists. |
+
+## Assumptions
+
+- `parent_session_id == None` is the canonical signal for the root stage agent
+  session in stored event envelopes.
+- Child OpenAI TODO lists are not part of the current stage sidebar contract.
+- The correct near-term fix is projection selection, not a frontend workaround
+  or a schema expansion.
+
+
+## Completed stages
+- **toolchain**: succeeded
+  - Script: `command -v cargo >/dev/null || { curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y && sudo ln -sf $HOME/.cargo/bin/* /usr/local/bin/; }; cargo --version 2>&1`
+  - Output:
+    ```
+    cargo 1.95.0 (f2d3ce0bd 2026-03-21)
+    ```
+- **preflight_compile**: succeeded
+  - Script: `cargo check -q --workspace 2>&1`
+  - Output: (empty)
+- **preflight_lint**: succeeded
+  - Script: `cargo +nightly-2026-04-14 clippy -q --workspace --all-targets -- -D warnings 2>&1`
+  - Output: (empty)
+
+
+Read the plan file referenced in the goal and implement every step. Make all the code changes described in the plan. Use red/green TDD.

stages/005-implement@1/provider_used.json

@@ -0,0 +1,6 @@
+{
+  "mode": "agent",
+  "provider": "openai",
+  "model": "gpt-5.5",
+  "reasoning_effort": "xhigh"
+}