draining-multi-piece-issue-incrementally

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name: draining-multi-piece-issue-incrementally description: Closes a multi-piece GitHub issue (e.g. [Bug] Patients page: missing pagination, no bulk/individual tag add, no CSV/XLSX export & template) by enumerating its sub-items, shipping one slice per cron tick as a file-disjoint pair (backend + frontend; or two backends; or backend + PRD), and only closing the issue after the final slice. Use when an open issue's body lists ≥3 sub-features. Encodes the discipline established across the #820 arc (14 commits across 10 ticks #181 → #197): pagination → bulk-tags → tag-chip → CSV → XLSX backend → XLSX button → template backend → template button → backend filters → frontend filters → import backend → import button → tag-remove backend → tag-remove UI. Each tick shipped 1 small slice; the issue closed naturally once 7/8 items were green.

Draining a multi-piece issue incrementally

When to use

A GitHub issue's body enumerates ≥3 distinct sub-features that EACH need their own implementation. Typical patterns:

• [Bug] issues like #820 with 4 numbered bug-reports (pagination + tags + export + filters)
• [Gap] issues with a multi-bullet acceptance-criteria list
• "List view missing X / Y / Z" patterns (common with Zylu-Gap items: #771 POS-002, #775 POS-006)

NOT this skill:

• Single-feature issues — ship as one small chore, close on land
• Multi-day issues where the work needs design (write a PRD instead — see writing-bonus-prd)
• Cross-cutting refactors (no per-piece slicing — needs a single bundled commit)

The discipline — 5-step loop

Step 1: Enumerate the sub-items

Read the issue body. List every distinct sub-feature as a checklist. The #820 enumeration was:

1. Pagination (server-side + UI)
2. Bulk tag-add (checkbox + modal + endpoint)
3. Individual tag-add (per-row chip)
4. CSV export (backend route + UI button)
5. XLSX export (new backend + new UI button)
6. Import template (backend route + UI button)
7. Source/Gender/Date-range filters (backend filters + frontend dropdowns)
8. Import upload (backend POST + frontend modal)

Estimate 1-2 slices per tick. 8 items = ~10 tick budget.

Step 2: Per-slice file-disjointness

Each slice should be ONE file-disjoint pair within a tick:

• Backend slice + frontend consumer slice (different agents OR same agent if dependency-ordered)
• Backend slice + PRD-writer (parallel; PRD touches docs/ only)
• Two independent backends (one route + one stub client)

Backend-then-frontend ordering matters when the frontend consumes a new endpoint. Ship backend in tick N, frontend in tick N+1. The interim state (backend exists, no UI yet) is FINE — operators/admins can curl the route to validate.

Step 3: Skip the "close" intent on every commit except the last

Each slice's commit message references the issue but does NOT include "Closes #". Only the FINAL slice gets a "Closes #" trailer. The mid-arc commits leave the issue open so:

• the issue's open status tracks "is this fully shipped"
• a partial-shipped state isn't lying about being done
• the user can gh issue list and see what's still in-flight

Mid-slice commit message pattern (no Closes):

feat(<area>): #<N> part <X> — <one-line>

<sub-feature description, 2-3 sentences>

<test counts, gate impact>

Final-slice commit message pattern:

feat(<area>): #<N> final piece — <one-line> — closes #<N>

<remaining sub-feature description>

Issue #<N> is now end-to-end: <list all <N> sub-items shipped>.

Step 4: GitHub closure trace

The issue may be auto-closed by the "closes #" trailer on the final commit. After push, run:

gh issue view <N> --json state --jq .state

If CLOSED: leave a final completion-trace comment summarising the arc (every commit, every test count, what's still potentially open as a follow-up). This is the audit trail for future agents trying to understand "what's the state of #?"

gh issue comment <N> --body "End-to-end shipped across ticks #<A> → #<B> (<date arc>):

**Backend (<N> endpoints):**
- ...

**Frontend (<N> affordances):**
- ...

**Tests:** <N> vitest cases + <N> supertest cases.

All <count> sub-items from the original bug report now ship end-to-end."

If NOT closed (because the trailer was on the wrong commit or the closure was suppressed): use gh issue close <N> --comment "..." to close manually with the same summary comment.

Step 5: After-arc completion-trace

Update CLAUDE.md's cron-learnings or TODOS.md if the arc surfaced a pattern worth codifying. The #820 arc surfaced:

• Sibling-spec rot pattern (different __tests__ paths)
• Export-trio pattern (CSV/XLSX/template + busy gate)
• Backend list-filter shared helper across 3 endpoints (applyPatientListFilters)

These got logged as cron-learning entries; the spec-rot got promoted to a one-line skill extension.

The #820 case-study — 14 commits across 10 ticks

Tick	Slice	Backend SHA	Frontend SHA	Notes
#181	bulk tag-add	wellness bulk-tags route	Patients.jsx checkbox + modal	44d8b950
#185	pagination + tag-chip	(uses existing limit/offset)	dd67f1a0	Same commit; backend was already capable
#187	XLSX export	ed00be9b /patients.xlsx	—	Backend first
#188	XLSX button	—	acf61032	Frontend consumer
#189	Import template	6b4831bb /import-template.csv	—	Backend first
#190	Template button	—	32386d08	Frontend consumer
#191	Filters (backend)	4fa87b0a list/CSV/XLSX	—	Shared helper across 3 endpoints
#192	Filters (frontend)	—	e74efa9e dropdowns	Frontend consumer
#193	Import upload	69ee75dc POST /patients/import	—	Backend first
#194	Import button	—	6ca1c236	Closes #820 in final commit trailer
#196	Tag-remove backend	5b610a56 removeTags param	—	Adjacent slice; #931
#197	Tag-remove frontend	—	c273f589	Closes #931

Key observations:

• Each tick shipped EITHER one slice OR a (backend, frontend) pair from adjacent slices
• The arc absorbed one fix-forward (2c8d349 sibling-spec rot fix) without derailing
• Every tick stayed file-disjoint with sibling parallel work (most ticks paired this work with a bonus-PRD agent)
• The arc closed naturally on tick #194; ticks #196-#197 were a SIBLING issue (#931 tag-remove) that shared the Patients.jsx surface

File-disjointness within a slice

A "backend slice" usually means:

• backend/routes/<area>.js (modify)
• backend/test/routes/<area>-<slice>.test.js (NEW)

A "frontend slice" usually means:

• frontend/src/pages/<area>/<Page>.jsx (modify)
• frontend/src/__tests__/<area>/<Page>.test.jsx (modify)

These two scopes are NATURALLY file-disjoint — perfect for a parallel-agent wave (backend agent + frontend agent in same tick). When you ARE pairing them in a single tick, make sure the backend ships BEFORE the frontend agent consumes it (e.g. backend agent commits, frontend agent rebases, then commits).

When dependency-ordered (frontend needs new backend), the wave can't run truly parallel — do backend first, then frontend next tick.

Anti-patterns

• Don't ship 2 slices in one commit. It makes review hard, makes git revert lossy, and breaks the "this tick shipped THIS slice" cron audit trail.
• Don't close the issue mid-arc. If you close on slice 4 of 8 and forget to re-open, the user thinks the issue is done.
• Don't write a single mega-PR. The cron's value is incremental shipping; a 14-file mega-PR loses that.
• Don't skip the completion-trace comment. Six months later, someone trying to understand "did we ship XLSX export?" should be able to read the GH issue and see the per-slice SHA list.
• Don't promote sub-features into new issues. If item 7 of 8 is "filters" and you decide it's too big, write a PRD (see writing-bonus-prd) and leave the rest of the arc continuing — don't fork the issue mid-arc.

Verification across slices

# At any point during the arc, check what's open vs shipped:
gh issue view <N> --json state,title --jq '{state, title}'
git log --oneline --grep "#<N>" | head -20

# After final slice, verify auto-closure or manual-close:
gh issue view <N> --json state --jq .state    # should be CLOSED

Related

• dispatching-parallel-agent-wave — file-disjoint scope per slice
• writing-bonus-prd — when the arc reveals a need for design call before continuing
• verifying-issue-before-pickup — check the issue isn't already closed BEFORE starting a slice
• auditing-cross-cutting-spec-impact — when a slice changes a response shape used by other surfaces
• CLAUDE.md cron-learning 2026-05-25 (#820 arc) — the canonical case-study