wave-pack-planner

name	wave-pack-planner
description	Dùng khi user nói 'plan wave', 'cluster gaps', 'wave-pack', 'next wave', hoặc khi cần group ≥3 disjoint gaps thành 1 wave-pack chạy parallel agents. Output: wave plan markdown (foundation PR-ready) + file-overlap matrix + 3-5 agent prompts. Codify pattern từ Wave Observability 2026-04-28 (3 gaps trong ~75 min vs ~6h serial = 5x speedup).
user-invocable	true
argument-hint	[gap-id ...] [--theme=<topic>]

/wave-pack-planner — Cluster-then-Spawn Methodology

Group các disjoint gaps thành wave-pack rồi spawn 3-5 worktree-isolated agents parallel. Đóng nhiều gaps trong 1 session, không serial PR queue.

When to use

• Sau /start-session báo "Wave-eligible: YES" (≥3 sub-tasks/gaps disjoint)
• Khi backlog có ≥5 gaps cùng theme (DR/Backup, Observability, Admin, Frontend bundle...)
• Trước khi "pick 1 gap rồi serial" — luôn check cluster-eligible trước
• Khi muốn validate pattern thêm 1 data point

When NOT to use

• 1-2 gaps độc lập (overhead wave plan > save time)
• Gaps share migration version slot (V_n collide khi parallel)
• Gaps share application.yml / single service file (rebase sequential)
• Foundation chưa ship (cần PR-0 trước)

Process (5 steps, ~30-45 min planning + spawn)

Step 1 — Identify candidate cluster (5 min)

Đọc documents/04-quality/gaps/ROADMAP.md §"Active wave queue (clustered)". Cluster định sẵn → chọn cluster đầu queue. Nếu không có:

• grep -l "Domain.*<theme>" documents/04-quality/gaps/GAP-*.md để find gaps cùng theme
• Output: 3-7 gap IDs candidate

Step 2 — File overlap analysis (10 min)

./.claude/skills/quality/wave-pack-planner/scripts/analyze-overlap.sh GAP-117 GAP-118 GAP-119

Script parse "Files" / "Affects" / "Proposed Fix" sections → output matrix:

File	Touched by	Conflict risk
...	A only	None
shared.yaml	B + C	SOFT — different sections
migration/V47__*.sql	A + B	HARD — version collide → SERIALIZE

Decision rule: ≥1 HARD conflict → either re-bucket gaps OR ship foundation PR first to defuse. Đọc reference/file-overlap-algorithm.md cho edge cases.

Step 3 — Bucket assignment (5 min)

Mỗi disjoint subset → 1 agent. Choose agent template:

• Pure markdown/runbook gap → assets/agents/docs-only-agent.md
• Backfill tests/fixtures → assets/agents/test-only-agent.md
• Dead code/unused/cleanup → assets/agents/p3-cleanup-agent.md
• Code change with TDD → assets/agents/feature-tdd-agent.md

Wave plan tự viết bằng wave-coordinator-agent.md template.

Step 4 — Foundation PR (10 min)

Tạo documents/03-planning/waves/wave-{date}-{theme}.md theo CANONICAL template documents/03-planning/waves/_TEMPLATE.md (validator source of truth — scripts/check-wave-plan-completeness.sh reads required sections from chính file đó).

reference/wave-plan-template.md là mirror tham khảo + thêm File-overlap + Lessons-learned sections; nếu drift giữa 2 file → canonical _TEMPLATE.md thắng.

MANDATORY — stubs cũng phải đầy đủ structure: Mọi wave plan PR (gồm cả minimal stub cho next-session scope) PHẢI có 8 sections ## 1. Brainstorm … ## 8. Log + 4 frontmatter fields (title, status, created, waves) để pass CI job wave-plan-completeness. Stub được phép leave ## 3. Scope / ## 4. State-Check Evidence TBD-at-session-start nhưng KHÔNG được skip heading. Recurrence ≥2 đã thấy (Wave 14 PR #2141 + Wave flow-kh3 stub 2026-06-04) — chạy validator local trước commit:

bash scripts/check-wave-plan-completeness.sh --paths documents/03-planning/waves/<file>.md

Pre-commit hook scripts/hooks/pre-commit tự động chạy validator này khi enable (git config core.hooksPath scripts/hooks).

Ship qua PR (PR-first per feedback_wave_plan_through_pr.md).

ROADMAP entry: thêm cluster vào §"Active wave queue", mark IN_PROGRESS.

Step 4.5 — Cross-layer check (api-contract first) — BẮT BUỘC

Per .claude/rules/contract-first-for-cross-layer.md v1.0.0 — wave plan có FE+BE scope (cross-layer) PHẢI có Bucket 0 Foundation ship documents/01-business/{domain}/api-contract.md TRƯỚC khi spawn FE bucket.

Decision flow:

1. Wave có cross-layer scope? Check rule §2 definition:
   • ≥1 bucket touch *-frontend/** AND ≥1 bucket touch *-core/** → CROSS-LAYER
   • Single bucket touch CẢ FE+BE → CROSS-LAYER
   • FE bucket consume API mà BE bucket cùng wave tạo → CROSS-LAYER
   • FE bucket dùng mock/fixture cho endpoint chưa tồn tại → CROSS-LAYER (contract violation)
2. Nếu CROSS-LAYER:
   • ls documents/01-business/{domain}/api-contract.md — tồn tại + đủ endpoint? Skip foundation. Thiếu/missing → add Bucket 0 Foundation vào §3 Scope FIRST
   • §4 State-Check Evidence: thêm row cho api-contract.md
   • FE bucket AC: "Endpoint consumption tuân thủ schema trong api-contract.md (Bucket 0 ship trước)"
   • BE bucket AC: "Controller signature + DTO match api-contract.md schema"
3. Spawn order: Bucket 0 merge FIRST → THEN FE+BE buckets parallel

Anti-pattern signal: wave plan có FE bucket + BE bucket nhưng KHÔNG có Bucket 0 Foundation row trong §3 Scope → STOP, add Bucket 0 hoặc justify exception qua commit trailer CONTRACT_FIRST_OVERRIDE: <reason>.

Worked example: Wave 32 v1 violated rule (no Bucket 0) → 8 sub-gap follow-up (GAP-272c/d/e/h/i/j/k/l). Wave 34 (Phase D) sẽ satisfy rule (Bucket 0 Foundation ships api-contract + MSW infra first).

Memory: feedback_fe_first_endpoint_proliferation.md (auto-loaded).

Step 4.55 — Pre-walk persona simulation (per pre-walk-persona-simulation-mandate.md v1.0.0) — BẮT BUỘC khi wave ship user-facing flow

Trigger: wave §3 Scope có ≥1 bucket touching user-facing flow class per pre-walk-persona-simulation-mandate.md §2 (signup / auth / invite / payment / tenant-switch / file-upload / email-driven / async / persona-attributed AC / multi-service workflow ≥3 services).

Decision flow:

1. Check rule §2 trigger pattern:
   • Bucket scope mentions signup / login / invite / claim / payment / 2FA / tenant-switch / upload / email-token-click? → CROSS-LAYER user-facing flow ✅ → MANDATORY pre-walk
   • Bucket scope pure refactor / infra / docs-only? → SKIP pre-walk
2. Nếu MANDATORY:
   • Add Bucket 0 (Pre-walk) row to §3 Scope per pre-walk-persona-simulation-mandate.md §6.2:

     | Bucket | Scope | Owner | Walk class |
     |---|---|---|---|
     | 0 (Pre-walk) | Spawn Opus background agent simulate <persona> walk <flow>, return ≥5 failure modes per pre-walk-persona-simulation-mandate.md §3 | Coordinator | n/a |
     | A | ... | <agent> | user-facing flow ✅ pre-walk required |
     

   • Spawn agent BEFORE merging Bucket A+B... (pre-walk findings inform batch fix scope)
   • Agent prompt: persona-based-business-review Pre-Walk Mode (per skill persona-based-business-review.md v1.3+ "Pre-Walk Mode" section)
   • Agent output saved artifact documents/04-quality/audits/persona-review/YYYY-MM-DD-pre-walk-<flow>.md
   • HIGH-confidence findings batch-fixed PRE walk (per rule §3.1 recommendation)
3. Skip exception cases:
   • Recent pre-walk simulation ≤30 ngày cho same flow scope → SKIP với note "Pre-walk reuse "
   • Hotfix urgency P0 production incident → use override trailer PRE_WALK_PERSONA_DEFER: per rule §6.4

Anti-pattern signal: wave plan có user-facing flow bucket nhưng KHÔNG có Bucket 0 (Pre-walk) row → STOP, add Bucket 0 hoặc justify exception qua commit trailer PRE_WALK_PERSONA_DEFER: <reason> + PRE_WALK_PERSONA_FOLLOWUP: <gap link>.

Worked example: Wave flow-kh1 G2 walk session 2026-06-04 surfaced 6 unexpected bugs trong ~3h. Per rule §5 retroactive analysis, 5 of 6 (83%) would have surfaced trong 5-min pre-walk persona simulation asking "Tôi là invitee — gặp lỗi gì? retry sao? token expired sao?". Cost-save: ~1.5h wall-clock per walk session + restored audit trust. Flow Verification Campaign §4 22-flow queue subsequent walks auto-comply prospectively.

Memory: feedback_pre_walk_persona_simulation.md (auto-loaded).

Step 4.6 — Quality calibration (model tier per stake)

Per feedback_sonnet_parallel_agent_crash.md + feedback_opus_rework_validation.md — classify wave stake → pick model tier cho parallel agents. Document choice trong wave plan §1 Brainstorm.

Stake matrix:

Wave stake	Model tier	Rationale
HIGH — Phase 1 BETA blocking, AI Branding feature, payment/lifecycle/security, multi-file refactor với strict compliance gates	Opus 4.7 full effort	Sonnet crashes mid-stream + skip verification trên multi-file refactor (Wave 32 v1 = 0/3 ship clean)
MEDIUM — FE component ports theo established patterns, doc-heavy, single-file additions	Opus medium effort (experiment first)	Measure wall-clock + audit findings vs full Opus baseline; adopt as default chỉ khi ship-clean parity
LOW — typo fix, doc sync, dep bump, cleanup	Sonnet/Haiku OK	Single-file low-complexity work; no compliance-gate burden

Model-agnostic gates (mandatory regardless of tier):

• §3.4 Verification gate: PR body paste output pnpm test --run <new-file> + mvn test -pl <module> xanh
• §3.5 AC Coverage table: PR body có table mapping mỗi AC line → file/test/verification
• §5.5 Anti-pattern grep: PR body confirm grep checks (e.g. no console.log, no TODO, no scaffold strings)

Anti-pattern signal: wave plan §1 Brainstorm không document model tier choice → reviewer hỏi "stake assessment?" trước approve. Default fallback: Opus 4.7 full effort (safer than under-spec).

Step 4.7 — Pre-spawn stale-check (per GAP-751 Option B)

BẮT BUỘC sau Step 4.6 và TRƯỚC Step 5 spawn agents. Mục tiêu: catch stale-OPEN gaps có code đã shipped wave trước → flip CSV inline → tránh waste agent spawn cost.

Trigger: mọi wave plan có gap-IDs trong §3 Scope.

Quy trình (~5-10 min coordinator inline):

1. Batch state-check mỗi gap-ID trong scope:

   for gap in <list GAP-IDs>; do
     # Read CSV row
     csv_row=$(grep "^$gap," documents/04-quality/gaps/gap-status.csv)
     status=$(echo "$csv_row" | awk -F, '{print $4}')
   
     # Read gap §Problem section file paths claim
     gap_file=$(echo "$csv_row" | awk -F, '{print $2}')
     # grep code paths matching gap scope
     # → if code exists matching all AC, flag potentially stale
   done
   

2. Inline flip stale gaps trước spawn:

   • Status OPEN/PARTIAL nhưng code shipped 100% → flip CSV → DONE per gap-done-discipline.md §2 + git mv to phase-X/closed/ per gap-folder-organization.md v2.0.0 §3.3
   • Status OPEN/PARTIAL với code shipped một phần → reframe AC + update completion_pct (PARTIAL X% → PARTIAL Y%)
   • Status OPEN với code chưa shipped → leave; spawn agent will work normally

3. Refine wave scope post-stale-check:

   • Nếu N buckets được flip stale → giảm spawn count tương ứng (vd 5 buckets dự kiến → 2 buckets thực sự cần spawn)
   • Update wave plan §3 Scope table với note: "Bucket X removed — GAP-NNN flipped DONE inline per pre-spawn stale-check (GAP-751 Option B)"

4. Document trong wave plan §4 State-Check Evidence (per audit-to-gap-pipeline.md §2.6):

   • List mỗi gap state-check finding (DONE inline / PARTIAL reframe / proceed normal)
   • Cite Option A hook auto-detect khi available — recurrence reduction expected

Anti-pattern: spawn N agents → agent N+1 báo "code đã shipped, gap stale" → coordinator flip inline → waste agent N+1 spawn cost. Pre-spawn check eliminates this.

Worked example (Wave br-7 retroactive): 4/5 buckets (GAP-215/216/217/218) state-check tại spawn time phát hiện code đã shipped Wave 5 Sub-PR 5.6b era. Pre-spawn check sẽ catch 4 stale → only Bucket E (GAP-742 greenfield) cần spawn → save ~30 min × 4 agents wall-clock + ~120k token agent spawn cost.

Cross-reference:

• audit-to-gap-pipeline.md §2.8 — fix-time state-check (this Step extends to wave-plan-time)
• .claude/hooks/audit-gate.py auto_close_referenced_gaps() — Option A complement (post-merge auto-flip)
• GAP-751 — full A+B specification

Step 5 — Spawn agents (1 message, multiple Agent calls)

BẮT BUỘC single message với N Agent tool uses parallel. KHÔNG sequential spawn (mất parallel benefit).

Agent A: isolation=worktree, prompt từ docs-only-agent.md + GAP-XXX context
Agent B: isolation=worktree, prompt từ feature-tdd-agent.md + GAP-YYY context
Agent C: isolation=worktree, prompt từ docs-only-agent.md + GAP-ZZZ context

Sau khi agents xong → coordinator merge sequential (A → B → C), resolve SOFT conflicts manually, close wave per reference/retrospective-checklist.md.

Step 5.5 — Pipeline next wave plan (during agent wait — eliminate dead-time)

Khi nào: ngay sau Step 5 (agents spawned background), trước khi merge starts.

What: Coordinator KHÔNG idle wait — propose Wave N+1 candidate (2-3 từ ROADMAP §🚀 Next Action) → user pick → draft Wave N+1 plan PR (state-check + brainstorm + scope + bucket allocation). Plan PR is docs-only, low conflict risk.

Constraints:

• Wave N+1 plan PR drafted but NOT merged until Wave N closure ships (per feedback_wave_plan_through_pr.md).
• Skip if coordinator already at ~150k+ context (per feedback_token_quota_spawn_timing.md).
• Skip if Wave N has high failure risk (untested infra) — finish Wave N + lessons first.
• Skip if user wants to pause between waves — respect pacing.

Math: sequential 2-wave block ~140min; pipelined ~110min = ~20-30% saving. See feedback_pipelined_wave_planning.md (auto-loaded memory).

Anti-pattern signal: if coordinator says "agents working background, anything else?" instead of "while agents run, pick Wave N+1?" — pipeline missed.

Skill contents

• SKILL.md — this file (entry point)
• reference/cluster-pattern.md — cluster-then-spawn methodology + decision tree
• reference/file-overlap-algorithm.md — overlap classification + edge cases
• reference/agent-spawning-template.md — how to write isolation:worktree prompts
• reference/retrospective-checklist.md — lessons-learned capture sau wave merge
• reference/wave-plan-template.md — markdown template cho wave plan
• reference/background-loop-fleet.md — documented /loop commands cho doc-sync, p3-sweeper, audit-cadence
• assets/agents/ — 5 agent prompt templates (docs-only, test-only, p3-cleanup, feature-tdd, wave-coordinator)
• scripts/analyze-overlap.sh — file overlap detector
• data/wave-history.jsonl — append-only log: wave + gaps + wall-clock + lessons

Rules

• Parallel spawn = 1 message, multiple Agent calls. Sequential Agent spawns = anti-pattern (mất parallel benefit)
• Foundation PR phải merge TRƯỚC khi spawn agents — agents branch off main, không off feature branch
• Mỗi agent dùng isolation: "worktree" — không share working dir
• Branch naming: feat/wave-{theme}-gap-{id-slug} — coordinator dễ track
• Coordinator merge sequential (A → B → C) — KHÔNG batch merge (CI race)
• Sau merge, bắt buộc clean worktrees + remote branches per feedback_parallel_agent_strategy.md rule #6
• Update data/wave-history.jsonl với wall-clock + lessons (data points cho future tuning)

Gotchas

• Worktree cross-contamination (Wave Obs Phase 2b): 2 agents sửa cùng 1 file (vd. adr/README.md) trong worktrees riêng → cuối khi merge git stash dance complex. Mitigation: file-overlap analysis (Step 2) phải catch — nếu HARD conflict, re-bucket
• Worktree absolute-path bug (Wave DR/Backup 2026-04-28): nếu prompt cite absolute paths (/home/.../scripts/foo.sh), agent có thể cd ra khỏi worktree vào main checkout → Write/commits land SAI branch. Wave DR/Backup case: Agent B's commit landed trên Agent C's branch → coordinator phải rebase + force-push để recover. Mitigation: prompt template (assets/agents/*-agent.md) bắt buộc dùng RELATIVE paths + agent verify pwd | grep worktrees trước Write/commit. Memory: feedback_worktree_absolute_path_contamination.md
• values.yaml shared section (Wave Obs Agent B + C): cùng file nhưng different YAML sections → git auto-merge thường OK. Nhưng nếu 1 agent reformats whole file → conflict. Mitigation: agent prompt instruct "chỉ touch section X, đừng reformat file"
• Stale wave plan trong waves/: collect-state.sh dùng mtime fallback → có thể chỉ vào wave đã ship. Mitigation: ROADMAP §"Active wave queue" là source of truth, không phải mtime
• Sequential merge timing: nếu Agent A's PR fail CI, đừng skip merge A để merge B trước — sẽ break dependency chain. Mitigation: wave plan ghi rõ merge order + rollback path
• Agent prompt drift: mỗi lần edit template → nhớ bump version + log entry. Otherwise next wave dùng stale template không match real workflow
• Overlapping gap closure timing: nếu 2 agents close 2 gaps trong cùng PR description → ROADMAP entry race. Mitigation: 1 PR = 1 gap closure, coordinator wave-closure entry batch
• Wall-clock metric noise: wall-clock include user response delay (approve permissions, answer Qs). Đo agent-time riêng nếu cần benchmark thực

Self-test

./scripts/analyze-overlap.sh GAP-121 GAP-143 GAP-144
# Expect output match documents/03-planning/waves/wave-2026-04-29-observability.md "File overlap analysis" section

Nếu output diverge → script bug, fix trước khi dùng skill cho wave mới.

Quality-target wave gate (added 2026-06-11 — per .claude/rules/wave-closure-scope-completeness.md v1.1.0 §2.5)

Khi wave tag/goal chứa quality-target (score suffix như -100, hoặc goal định lượng "rubric ≥N"), plan §5 Verification Gates BẮT BUỘC khai báo Quality-target closure gate:

1. Metric + ngưỡng cụ thể (vd "landing rubric ≥90/100 re-score sau wave").
2. Cam kết: "Gap surfaced trong wave (bucket ship / G1-G2 walk / UI review) thuộc closure scope — fix trong wave TRƯỚC khi flip status: complete. Defer cần user explicit approve qua trailer WAVE_QUALITY_TARGET_DEFER:."
3. Budget cho vòng fix-found-gaps (walk → catalog → batch-fix → re-walk, per feature-ship-runtime-walk-mandate.md §3.4) — đừng plan wave quality-target mà 0 giờ cho vòng fix.

Bài học gốc (2026-06-11): wave landing-100 flip complete khi rubric chưa re-score + gap defer → user flag "đã là 100 thì ko còn gap" → fix-pack re-open. Tên wave là lời hứa — đặt -100 thì closure gate phải tương xứng, hoặc đừng đặt tên đó.

Wave numbering (added 2026-05-23 — per .claude/rules/wave-tag-numbering-convention.md v1.0.0)

Từ Wave thesis-1 (2026-05-23) trở đi, wave mới dùng tag-based format thay vì sequential counter (Wave 108, Wave 109, ...). Wave 01-107 cũ giữ sequential — KHÔNG backfill.

Format

wave-{tag_primary}-{counter}[-{descriptor}]

• tag_primary lowercase-kebab semantic (thesis / beta / security / meta / ops / feature-{domain} / hotfix / release-{N})
• counter monotonic integer per tag (thesis-1, thesis-2, thesis-3, ...)
• descriptor optional kebab-case (closure / hardening / fix-bugs)

Examples

Artifact	Format
Wave identifier	wave-thesis-1-closure
Plan filename	documents/03-planning/waves/wave-2026-05-23-thesis-1-closure.md
Branch	wave/thesis-1-closure
Plan commit	plan(wave-thesis-1): closure 6 bucket parallel
Bucket commit	feat(wave-thesis-1-bucket-A): citation-extract skill
wave-history.jsonl entry	{"wave":"thesis-1","tag_primary":"thesis","tags_secondary":["doc","beta-prep","meta"],"counter":1,...}

Frontmatter trong wave plan file

---
wave: 1
tag_primary: thesis
tags_secondary: [doc, beta-prep, meta]
counter: 1
date_launch: 2026-05-23
status: planning | in-progress | shipped | abandoned
---

Multi-tag

1 wave có 1 primary tag (drives counter) + N secondary tags (descriptive only). Query "tất cả wave touching beta-prep":

jq 'select(.tag_primary == "beta-prep" or ((.tags_secondary // []) | index("beta-prep")))' wave-history.jsonl

Counter rules

• Monotonic per tag, no skip, no reset (thesis-1, thesis-2, thesis-3...)
• Sub-wave dùng descriptor (wave-thesis-1-fix-bundle) thay vì decimal (wave-thesis-1.1 BANNED)
• Tags độc lập (thesis-3 không liên quan beta-3)

Hybrid history query

wave-history.jsonl chứa 2 format coexist (legacy sequential Wave 01-107 + new tag-based từ Wave thesis-1). Query script PHẢI handle cả 2:

# Match by theme keyword (fuzzy) for legacy + by tag_primary for new
jq 'select(
  .tag_primary == "thesis" or
  (.tags_secondary // [] | index("thesis")) or
  (.theme | ascii_downcase | test("thesis|khóa luận"))
)' wave-history.jsonl

Reference đầy đủ: .claude/rules/wave-tag-numbering-convention.md.

Related

• Memory: feedback_wave_pack_cross_gap_clustering.md (cluster pattern motivation)
• Memory: feedback_wave_plan_before_serial_prs.md (anti-pattern serial PR)
• Memory: feedback_parallel_agent_strategy.md (worktree isolation rules)
• Memory: feedback_wave_plan_through_pr.md (PR-first cho wave plan)
• Skill: workflow/start-session/SKILL.md (Step 4.5 wave-eligibility hint)
• Skill: workflow/quality-plan/SKILL.md (alternative planning skill)
• Skill: workflow/gap-to-pr-converter.md (single-gap-to-PR; this skill = N-gap-to-wave)
• Rule: .claude/rules/post-wave-audit-mandate.md §4 (post-wave audit cadence)
• Rule: .claude/rules/contract-first-for-cross-layer.md (Step 4.5 reference)
• Memory: feedback_fe_first_endpoint_proliferation.md (Step 4.5 motivation)
• Memory: feedback_sonnet_parallel_agent_crash.md (Step 4.6 motivation)
• Memory: feedback_opus_rework_validation.md (Step 4.6 working solution)

Log

• 2026-05-07 (v1.2): Added §Step 4.5 Cross-layer check (api-contract first) per new .claude/rules/contract-first-for-cross-layer.md v1.0.0 + §Step 4.6 Quality calibration (model tier per stake) per feedback_sonnet_parallel_agent_crash.md + feedback_opus_rework_validation.md. Wave 32 v1 (Sonnet 4.6, no contract foundation) → 0/3 ship clean + 8 sub-gap follow-up; Wave 32 rework (Opus 4.7 + verification gates) → 4/4 ship clean. Both lessons codify into skill steps. Reviewer: @nguyenvankiet (solo-dev MINOR — additive workflow guidance, no constraint loosening).
• 2026-05-06 (v1.1): Added §Step 5.5 — Pipeline next wave plan (during agent wait). Codifies pattern user requested after Wave 27 retro: coordinator drafts Wave N+1 plan PR while Wave N agents run background → 0 dead-time between waves (~20-30% saving per 2-wave block). Paired with memory feedback_pipelined_wave_planning.md (auto-loaded). Reviewer: @nguyenvankiet (solo-dev MINOR — additive workflow guidance, no constraint loosening).
• 2026-04-28 (v1.0): Skill created. Codifies methodology demonstrated by Wave Observability 2026-04-28 (3 gaps GAP-121/143/144 closed in ~75 min wall-clock = ~5x speedup vs serial). Wave Obs lessons-learned (worktree cross-contamination Phase 2b, values.yaml shared-section soft-merge) captured in §Gotchas. Day 2 deliverable per "Option C hybrid" strategy (execute then codify) decided in 2026-04-28 morning session. Reviewer: @nguyenvankiet (solo-dev MINOR, new skill paired with check-skill-conventions PASS + self-test green).