Spec to Repo

A delivery-focused skill that bridges product spec to repository work. Where PRD-writing skills focus on what to build, this skill focuses on how to break it down for execution — the ticket decomposition, branch strategy, PR sequencing, and acceptance criteria that make a spec actually ship.

When to use this skill

• Translating a PRD or feature brief into a sequence of tickets
• Designing the branch + PR sequence for a multi-week feature
• Auditing an existing ticket decomposition for risk (big tickets, hidden dependencies)
• Defining definition-of-done that covers code, tests, docs, telemetry
• Planning incremental shipping (feature flags, canaries, dark-launch)
• Reviewing a decomposition before sprint planning to avoid mid-sprint surprises

Inputs the advisor expects

• The PRD or spec document
• Target ship window (1 sprint? 1 month? 1 quarter?)
• Engineering team size + composition (FE, BE, ML, mobile)
• Risk profile (greenfield vs production-impacting)
• Feature-flag and rollout posture

Clarify First

Before generating the repo plan, settle the inputs below. When one is missing or vague and would change the result, ask about it; when it wouldn't, use a sensible default and say which one you used.

• The PRD or spec: the user-facing capabilities to decompose (drives the epic→ticket tree).
• Target ship window: one sprint, month, or quarter (drives ticket sizing and PR sequencing).
• Team composition: FE, BE, ML, mobile (decides parallel paths and vertical-slice tickets).
• Feature-flag and rollout posture: flagged/dark-launch vs direct ship (drives PR sequencing and definition-of-done).

Ask about the two or three inputs that matter most for this request, not the whole list. If the user wants a result straight away, produce it and state your assumptions at the top.

Workflows

Workflow 1 — Decompose a PRD into tickets

1. Pull the PRD; identify the user-facing capabilities.
2. Run prd_to_tickets_decomposer.py with the user stories + technical notes to surface a candidate ticket tree (epic → tickets → subtasks) with size estimates and dependencies.
3. Manually review; tune for team-specific patterns.

python3 spec-to-repo/scripts/prd_to_tickets_decomposer.py \
  --input prd.json --format markdown

Workflow 2 — Validate the branch and PR plan

1. Capture proposed branch + PR sequence.
2. Run pr_scope_analyzer.py to flag oversized PRs, missing tests, missing telemetry, and risky merges.
3. Adjust before opening PRs.

python3 spec-to-repo/scripts/pr_scope_analyzer.py \
  --input pr_plan.json --format markdown

Workflow 3 — Lint branch names against convention

1. Capture branch list (e.g., git branch --list).
2. Run branch_naming_validator.py to flag non-conformant names.

python3 spec-to-repo/scripts/branch_naming_validator.py \
  --input branches.txt --format markdown

Decision frameworks

Ticket sizing

Size	Effort	Description
XS	< 0.5 day	Trivial; usually skip ticketing
S	0.5–1 day	One simple change
M	1–3 days	Single feature, well-scoped
L	3–5 days	Multi-day work; should split if possible
XL	> 5 days	Always split — too big for confident estimate

A ticket that's L or XL almost always hides a missing decomposition. Push back on yourself.

The ticket tree

Epic — large product feature ("Notifications v2")
├── Story — user-facing capability ("As a user I can mute by channel")
│   ├── Ticket — one engineering work item (backend, frontend, infra)
│   │   └── Subtask — atomic step (optional)

Most orgs:

• Epic ≈ PRD-sized scope
• Story ≈ one user-facing slice
• Ticket ≈ one PR (or pair of PRs: BE + FE)

The "vertical slice"

Best ticket: ships a small user-visible improvement end-to-end.

• Backend change + frontend change + tests + telemetry + docs in one ship
• Better than: BE-only ticket waiting for FE-only ticket waiting for QA

When you can't slice vertically (e.g., backend is weeks before frontend):

• Use feature flags to ship behind a switch
• Dark-launch backend to validate before frontend
• Communicate the lag explicitly

PR sequencing

For a multi-PR feature:

1. PR 1 — Infrastructure / scaffolding (no behavior change)
2. PR 2 — Backend changes (behind flag; no frontend uses it)
3. PR 3 — Frontend changes (behind flag; tests pass with flag on/off)
4. PR 4 — Telemetry + analytics events
5. PR 5 — Documentation + runbook
6. PR 6 — Flag enablement (small change; reviewable cleanly)

Each PR < 400 lines if possible. Reviewability collapses above 400.

Definition of done

Per ticket:

• Code: written, reviewed, merged
• Tests: unit + integration as appropriate
• Telemetry: events fired (and verified)
• Docs: README / runbook / API doc updated as needed
• Accessibility: meets the project bar
• Feature flag: configured (if applicable)
• Rollout plan: defined for non-flagged ships

Per epic:

• All tickets complete
• Feature behind flag in production for 1+ week (if risky)
• Flag enabled for X% (canary), then ramped
• Telemetry shows expected behavior
• Customer-facing comms drafted (if applicable)

Common engagements

"Help me decompose this PRD"

1. List user-facing capabilities (1-line each).
2. For each, list the backend, frontend, infra, telemetry, docs work.
3. Estimate; flag anything > 3 days for further breakdown.
4. Sequence: scaffolding first, behavior next, flag enablement last.
5. Identify cross-team dependencies; engage before sprint start.

"Our team is shipping huge PRs"

1. Audit the last 10 PRs: median size, P95 size.
2. Identify the patterns: monolithic services + flag-less work + slow review.
3. Pilot: feature flags + ticket-first decomposition + PR size SLA.
4. Track: median PR size + lead time week-over-week.

"Help me plan the rollout"

1. Define a successful launch criterion (e.g., < 0.5% error rate at 50%).
2. Identify the kill switch (feature flag or quick-revert).
3. Plan ramps: 1% → 5% → 25% → 50% → 100% with bake time.
4. Define rollback criteria + comms plan.
5. Coordinate with on-call + support.

Anti-patterns to avoid

• Decomposition as wishful thinking. "3-day estimate" with no break-down is a 2-week-actual.
• Sequential ticket tree (everyone waits). Plan parallel paths.
• Hidden dependencies on other teams. Surface them in decomposition.
• No feature flag. Shippable in chunks but every change goes to all users immediately.
• PRs > 1000 lines. Reviewability dies; bugs hide.
• DoD that's just "code merged." Forgets tests, docs, telemetry.
• Ticket = a day of work. Sometimes tickets are 30 minutes; sometimes 3 days.

Scope & Limitations

In Scope:

• Decomposing a PRD, described as user capabilities, technical notes and team, into an epic, story and ticket tree with prd_to_tickets_decomposer.py, flagging oversized tickets and cross-team dependencies
• Checking a planned PR sequence with pr_scope_analyzer.py for oversized PRs, missing tests, telemetry or docs, risky merges and ordering problems
• Linting branch names against a configurable pattern with branch_naming_validator.py
• Guidance on ticket sizing, vertical slices, PR sequencing, definition of done and staged rollout

Out of Scope:

• Writing the PRD itself (see project-management/execution/create-prd/)
• Creating tickets in Jira or Linear (see project-management/jira-expert/ and project-management/linear-expert/)
• Feature flag platform design (see engineering/feature-flags-architect/)
• Reviewing actual code changes (see engineering/pr-review-expert/)

Important Caveats:

• The decomposer does not parse PRD prose. It works from a JSON of capabilities, and effort comes from the estimated_days the user enters.
• The PR analyzer reads a plan with estimated line counts, not real diffs. The branch validator checks a list of names and does not touch the git repository.
• Size limits such as splitting tickets over 3 days or keeping PRs under 400 lines are rules of thumb. Teams should tune them to their own history.

References

• references/spec-to-ticket-decomposition.md — patterns for breaking specs into tickets
• references/branch-strategy-for-features.md — branching, feature flags, dark-launch
• references/pr-discipline-and-conventions.md — PR size, review, definition-of-done

Related skills

• product-team/agile-product-owner — sprint planning, prioritization
• engineering/feature-flags-architect — flag strategy
• engineering/observability-designer — SLO / telemetry
• c-level-advisor/vpe-advisor — broader delivery context
• project-management/ skills — ticket / sprint management tooling