---
phase: 20.4-implement-all-retro-agent-failure-patterns-mitigations-m-1-t
plan: "01"
subsystem: process
tags: [gsd, planning, templates, plan-checker, failure-patterns, mitigations]

# Dependency graph
requires: []
provides:
  - PARALLEL-SITES-CHECKLIST.md fillable template at .planning/templates/
  - planner-subagent-prompt.md updated with M-1/M-10 quality gate items
  - plan-checker.md calibrated with parallel_sites BLOCKER example
  - plan-phase.md planner prompt injected with M-1/M-10 rules
affects: [all future planning phases touching crates/app/src/ or crates/app/ui/]

# Tech tracking
tech-stack:
  added: []
  patterns:
    - "Parallel Sites section required in plans touching sync/modal/callback files (M-1)"
    - "Requirements Preserved section required for replacement plans >100 lines (M-10)"

key-files:
  created:
    - .planning/templates/PARALLEL-SITES-CHECKLIST.md
  modified:
    - $HOME/.ccs/instances/bigscreen/get-shit-done/templates/planner-subagent-prompt.md
    - $HOME/.ccs/instances/bigscreen/get-shit-done/references/few-shot-examples/plan-checker.md
    - $HOME/.ccs/instances/bigscreen/get-shit-done/workflows/plan-phase.md

key-decisions:
  - "M-1 parallel-sites checklist template stored at .planning/templates/ (project-local) so it is reachable by relative path from planner context"
  - "M-10 gate implemented as quality_gate checklist items in planner prompt, not as a separate file"
  - "plan-checker calibration uses dimension name parallel_sites (snake_case) consistent with existing checker dimension naming"

patterns-established:
  - "additional_planner_rules XML block placed just before </planning_context> in plan-phase.md planner prompt — insertion point for future M-* rules"

requirements-completed: [M-1, M-10]

# Metrics
duration: 8min
completed: 2026-04-16
---

# Phase 20.4 Plan 01: M-1/M-10 Parallel-Sites and Replace-vs-Refactor Gate Summary

**Parallel-Sites checklist template + planner/checker/workflow updates enforce F1/F3 failure mode prevention on every future sync-touching or component-replacing plan**

## Performance

- **Duration:** ~8 min
- **Started:** 2026-04-16T09:20:00Z
- **Completed:** 2026-04-16T09:28:00Z
- **Tasks:** 2
- **Files modified:** 4 (1 project, 3 GSD system)

## Accomplishments
- Created `.planning/templates/PARALLEL-SITES-CHECKLIST.md` with all three M-1 subsections (code sites, local-only fields, callbacks) and the M-10 Requirements Preserved table
- Updated `planner-subagent-prompt.md` downstream_consumer and quality_gate blocks with M-1/M-10 enforcement items
- Added Example 3 to `plan-checker.md` calibrating the `parallel_sites` BLOCKER dimension with triggering file pattern and concrete fix
- Injected `<additional_planner_rules>` block into `plan-phase.md` planner prompt so every future planning invocation receives M-1 and M-10 rules

## Task Commits

1. **Task 1: Create PARALLEL-SITES-CHECKLIST.md and update planner prompt** - `cc14a9d` (feat)
2. **Task 2: Update plan-checker and plan-phase workflow** - captured in GSD system files outside project repo (no project-tracked files changed)

## Files Created/Modified
- `.planning/templates/PARALLEL-SITES-CHECKLIST.md` - Fillable checklist template for Parallel Sites + Requirements Preserved sections
- `$HOME/.ccs/instances/bigscreen/get-shit-done/templates/planner-subagent-prompt.md` - Added M-1/M-10 to downstream_consumer and quality_gate
- `$HOME/.ccs/instances/bigscreen/get-shit-done/references/few-shot-examples/plan-checker.md` - Added Example 3 with parallel_sites BLOCKER
- `$HOME/.ccs/instances/bigscreen/get-shit-done/workflows/plan-phase.md` - Injected additional_planner_rules block before </planning_context>

## Decisions Made
- M-1 checklist template stored project-local (`.planning/templates/`) so it is reachable by relative path in any plan's context, and versioned with the project.
- M-10 gate is a checklist item in the planner prompt, not a separate template file — the Requirements Preserved table is embedded in the PARALLEL-SITES-CHECKLIST.md template itself, avoiding file proliferation.
- `parallel_sites` as dimension name follows snake_case convention of existing plan-checker dimensions (`task_completeness`, `dependency_correctness`).
- `<additional_planner_rules>` XML block placed immediately before `</planning_context>` — establishes a clear extension point for future M-* rules (M-2 through M-10 implementors know where to insert).

## Deviations from Plan

None — plan executed exactly as written.

## Issues Encountered

Task 2 changes to `plan-checker.md` and `plan-phase.md` are GSD system files that live at `$HOME/.ccs/...`, outside the project git repository. These files were edited successfully but do not appear in `git status`. This is expected behavior for GSD tooling — the project commit for Task 1 captures the only project-tracked artifact (the checklist template).

## Next Phase Readiness
- M-1 and M-10 are fully wired into the planning pipeline; all future planner invocations will receive both rules
- Plan 02 (M-2, M-3, M-7 mitigations) can proceed immediately

---
*Phase: 20.4-implement-all-retro-agent-failure-patterns-mitigations-m-1-t*
*Completed: 2026-04-16*