---
id: BACK-235
title: Consolidate duplicate AC sections and overwrite Implementation Notes
status: Done
assignee:
  - '@codex'
created_date: '2025-08-17 16:05'
updated_date: '2025-08-26 17:20'
labels:
  - cli
  - bug
dependencies: []
priority: high
---

## Description

Fix two related content consistency issues:

1) Acceptance Criteria consolidation: The AC update logic now consolidates any duplicate AC sections (legacy header-only or marked with AC:BEGIN/AC:END) into one marked section at the first AC location, renumbered and stable.

2) Implementation Notes overwrite: Editing with --notes replaces the entire Implementation Notes section content (no append). If missing, the section is created and placed after Implementation Plan if present, else after Acceptance Criteria or Description.

Tests updated accordingly; viewers unaffected.
## Acceptance Criteria
<!-- AC:BEGIN -->
- [x] #1 When a task already has Implementation Notes, editing with --notes replaces the entire section content
- [x] #2 When missing, Implementation Notes is created and placed after Implementation Plan if present, else after Acceptance Criteria or Description
- [x] #3 Multi-line notes preserved; no duplicate Implementation Notes sections created
- [x] #4 CLI and TUI viewers display the replaced content correctly
- [x] #5 Update existing tests to expect overwrite semantics (no append)
- [x] #6 Detect multiple AC sections (with markers) and consolidate to a single section when updating
- [x] #7 If both legacy (no markers) and marked sections exist, migrate to one marked section
- [x] #8 Guarantee: after any AC edit, the file contains exactly one AC section with correct numbering
- [x] #9 Add tests: starting from content with duplicated AC sections, after an AC update only one section remains with expected content
<!-- AC:END -->


## Implementation Plan

1. Update serializer: overwrite Implementation Notes on edit
2. Preserve section insertion order when missing (after Plan, else AC/Description)
3. Update tests to expect overwrite behavior (no append)
4. Run Biome check + tests; adjust as needed
5. Document behavior via task notes

## Implementation Notes

Changed Implementation Notes behavior to overwrite on edit.

Summary of changes:
- src/markdown/serializer.ts: updateTaskImplementationNotes now replaces the entire "Implementation Notes" section content when --notes is used.
- Section creation preserved: when missing, the section is inserted after Implementation Plan if present, else after Acceptance Criteria or Description.
- Tests updated: src/test/implementation-notes.test.ts and src/test/task-edit-preservation.test.ts now expect overwrite semantics.
- Verified CLI/TUI viewers handle replaced content correctly; no duplicate sections created.
- Ran Biome check and targeted tests: all green.

Rationale: aligns with DoD/PR-style notes (single clean description).
