Create Product Plan + Architect Handoff

Goal

Turn a user prompt into a single, actionable PM plan that:

• •frames the user problem and desired outcomes,
• •defines scope, principles, success metrics, and delivery phases,
• •provides an execution checklist that engineering can follow,

Minimal workflow

Throughout the entire workflow, operate in read-only mode. Do not write or update files.

1. •

   Scan context quickly (product + system)

   • •Read README.md and obvious docs (docs/, CONTRIBUTING.md, ARCHITECTURE.md).
   • •Identify product surface area: UI/UX entry points, API boundaries, data stores, integrations, etc. Ask user if uncertain.
   • •Identify existing patterns: feature flags, telemetry, authn/authz, config, error handling, etc. Ask user if uncertain.
   • •Note relevant existing modules/files only as pointers (no edits).
2. •

   Clarify only the highest-leverage unknowns

   • •Ask questions if truly blocking. Questions are given together with possible options.
   • •Prefer multiple-choice (persona, platform, “must-have” constraints, definition of success).
   • •If not blocked, state assumptions explicitly and proceed.
3. •

   Produce an execution-ready plan using the template below

   • •Start with 1 short paragraph describing the user problem and approach.
   • •Clearly call out scope (in/out) and non-goals.
   • •Provide success metrics (leading + lagging indicators).
   • •Provide a phased delivery plan (MVP → V1 → later) when appropriate.
   • •Provide a small checklist of action items (default 8–12 items), ordered: discovery → design → implementation → validation → analytics → rollout.
   • •Using Vertical Slice planning pattern, which focuses on shipping one thin end-to-end path (UI → API → data → observable output) first.
   • •If unknowns remain, include Open questions.
4. •

   Output only the plan using the template below (no meta commentary).

5. •

   Write the plan to the PLAN.md

Plan template (follow exactly)

# Plan

<1–3 sentences: user problem, intended outcome, and approach (phased if needed).>

## Requirements
- Functional (must-have):
- Functional (nice-to-have):

## Scope
- In:
- Out:
- Non-goals:

## Success metrics
- Leading indicators:
- Lagging indicators:
- Guardrails (quality, performance, safety):

## Delivery approach
- MVP:
- V1:
- Later:

## Architect handoff (to concretize implementation and handoff to the developer team)
- System boundaries & dependencies:
  - Upstream:
  - Downstream:
  - External services/integrations:
- Interfaces & contracts:
  - Public API/CLI/UI contracts (inputs/outputs, error model):
  - Data model changes (entities, fields, migrations):
  - Permissions/authz model:
- Observability:
  - Events to track (name + properties):
  - Logs/traces/metrics (what must exist for debugging and SLOs):
  - Dashboards/alerts (what would indicate success/failure):
- Rollout & operations:
  - Feature flag strategy:
  - Backward compatibility considerations:
  - Rollback plan:
- Test strategy:
  - Acceptance criteria (Given/When/Then bullets):
  - Unit/integration/e2e coverage focus:
  - Edge case matrix (top risks to test):

## Action items
[ ] <Step 1: discovery / alignment>
[ ] <Step 2: UX spec / requirements>
[ ] <Step 3: architect handoff artifacts prepared>
[ ] <Step 4: implementation tasks breakdown>
[ ] <Step 5: testing & verification>
[ ] <Step 6: staged rollout>
[ ] <Step 7: post-launch review & iteration>

## Risks & edge cases (Optional)
- <Risk/edge case 1 + mitigation>
- <Risk/edge case 2 + mitigation>
- <Risk/edge case 3 + mitigation>

## Open questions
- <Question 1>
- <Question 2>
- <Question 3>

Guidance for “execution-ready but implementation-agnostic”

Do:

• •Specify contracts (inputs/outputs/errors), not algorithms.
• •Specify states and user-visible behaviors.
• •Specify data entities/fields at the conceptual level (what exists, not how indexed).
• •Specify acceptance criteria in Given/When/Then form.
• •Specify rollout mechanics (flag, staged release, rollback triggers).
• •Point to likely modules/files only as “touchpoints”.

Avoid:

• •Picking libraries/frameworks/algorithms unless the user explicitly requests.
• •“Just implement X” without defining behaviors, metrics, and contracts.
• •Unbounded scope; always define non-goals.