Cursor rule

1---
2description: "PLANNING SPINE STEP 2 of 3 — Slice the work: break a scoped PRD into vertical-slice stories in specs/epics/. Use after scope-work (step 1), before plan-work (step 3). Not a substitute for scope-work or plan-work."
3alwaysApply: false
4---
5 
6# story: e45s29
7 
8# Slice Tasks
9 
10> **Spine position:** Step 2 — scope-work → slice-tasks → plan-work.
11 
12Produce **epic capsule story tasks** in `specs/epics/eNN-slug/` — vertical slices, each independently deliverable and testable. Output: decoupled `eNNsYY-tasks.yaml` files with runnable verify commands. Legacy `specs/epics/ (see slice-tasks)` is deprecated; use capsule dirs + `execution-status.yaml`.
13 
14## Pre-flight
15 
16- [ ] Does `specs/product/SCOPE_LATEST.yaml` exist? If not, run `scope-work` first — you can't slice what you haven't bounded.
17- [ ] Is the `release-plan.yaml` populated with the epics you're slicing? Epic IDs (e01, e02…) should exist before you create stories.
18- [ ] Do you understand the difference between a horizontal layer and a vertical slice? (See anti-patterns below.)
19 
20## Process
21 
220. **Read planning-context.yaml** — If `specs/planning-context.yaml` exists, read it first:
23```bash
24   test -f specs/planning-context.yaml && echo "Context found" || echo "No context — starting fresh"
25```
26   Use `feature_name`, `constraints`, and `out_of_scope` to inform slice boundaries. `key_decisions` in the file may constrain how stories are cut (e.g., "no external deps" constrains slice 2). If absent, proceed normally.
27 
281. **Read context** — Read `specs/product/SCOPE_LATEST.yaml` and/or `specs/release-plan.yaml`. Understand what the epic delivers end-to-end.
29 
302. **Cut tracer-bullet slices** — Identify the thinnest possible vertical path through the stack that delivers user value. Start with this slice; it will catch integration issues first. For example:
31   - A search feature: first slice is "user types query → API returns results" (no filters, no pagination, no ranking — just the plumbing working end-to-end).
32   - A checkout flow: first slice is "user clicks buy → order created" (no payment, no inventory, no email).
33 
343. **Assign BCPs** — For each story, estimate Business Complexity Points (1–13). A 1-BCP story is a trivial change (one file, one concept). A 13-BCP story is a major feature across multiple modules. If a story exceeds 8 BCPs, consider splitting it.
35 
364. **Each story** writes:
37   - `eNNsYY-tasks.yaml` with `story_id`, `title`, `status`, `bcps`, `tasks[]` (each with `id`, `description`, `verify`, `status`)
38   - Story spec `.md` files are written by `plan-work` and follow countable-story-format.md
39   - The epic capsule manifest (`epic.yaml`) is updated to list the story ID and BCPs
40   - **Requirement deltas (e45s29):** Stories that alter existing behavior MUST carry `delta:` in `epic.yaml` (`ADDED` | `MODIFIED` | `REMOVED` | `RENAMED`). `plan-work` expands deltas into full before/after requirement text.
41 
425. **Order by WSJF** in `release-plan.yaml` epic list — highest WSJF first. Weight-shortest-job-first ensures the highest value arrives earliest.
43 
446. **Validate slices** — Every slice must answer: "If this story ships, does a user get new value?" If the answer is "no, they need a later story too", the slice is too horizontal — cut vertically deeper.
45 
46> **HARD GATE** — No horizontal-only slices ("add all models") without a vertical path that proves integration. Every story must be independently demonstrable, even if it only handles the happy path.
47 
48> **HARD GATE** — Each task's `verify:` field must contain a runnable command (not "manually check" or "review visually"). If verification requires manual steps, prefix with `verify-script:` and write the steps in the story file.
49 
50## Anti-Patterns
51 
52- **Layer cakes** — "Week 1: all models. Week 2: all controllers. Week 3: all views." This hides integration risk until the end. Every story must cut through all layers.
53- **Too-small slices** — If a slice takes < 30 minutes to implement, it's probably noise. Combine with adjacent slices.
54- **Too-large slices** — If a slice takes > 3 days, it's an epic, not a story. Split further.
55 
56## Output
57 
58- `specs/epics/eNN-slug/eNNsYY-tasks.yaml` — per-story task breakdown with verify commands
59- `specs/epics/eNN-slug/epic.yaml` — updated with story list and BCPs
60- `specs/release-plan.yaml` — updated WSJF ordering (if needed)
61 
62## Verify
63 
64→ verify: `[ "$(find specs/epics -name '*-tasks.yaml' 2>/dev/null | wc -l | tr -d ' ')" -gt 0 ]`
65 
66 
67<!-- story: e03s01 -->
68