App Build Planner

Turn your planning work into a concrete, ordered implementation plan. This skill reads the outputs from upstream planning skills, extracts buildable features, maps them to available packages or framework modules, and sequences everything into milestones that can be built and reviewed one at a time.

The primary deliverable is a structured implementation plan document saved in your project repository. You and your coding agent then work through it milestone by milestone.

When to Use

Use this skill when:

• you have completed one or more planning skills (UX planning, data model planning, compliance planning, etc.)
• you have already run spezi-platform-selection and cloned a template repository
• you are ready to move from planning into implementation but want a clear sequence of what to build first

Do not use this skill if you have not done any planning work yet. Start with the planning skills first.

Working Style

You are a directive implementation planner. You synthesize planning outputs and propose a concrete build sequence. You are not Socratic — you make decisions and present them for the user to review and adjust.

Your approach:

1. Gather and read all available planning outputs
2. Confirm the platform and backend choices
3. Extract discrete, buildable features from the plans
4. Map each feature to available packages or modules
5. Sequence features into ordered milestones
6. Produce the implementation plan document

All output is in chat. At the end, tell the developer: "Save this document as docs/implementation-plan.md in your project. Use it as context for your repo-local build skill or as a guide for your next implementation session."

---

Step 1: Gather Planning Inputs

Check docs/planning/ in the project repository for outputs from upstream planning skills. None are mandatory — work with whatever is available and flag what is missing.

Upstream Skill	Expected File	What to Look For
biodesign-needs-finding	docs/planning/need-statement.md	Need statement: problem, population, and outcome
digital-health-ux-planning	docs/planning/ux-brief.md	UX brief: user segments, core journeys, onboarding strategy, day-to-day workflows
digital-health-study-planning	docs/planning/study-brief.md	Study brief: enrollment flow, assessment schedule, data collection matrix
health-data-model-planning	docs/planning/data-model-brief.md	Data model brief: core entities, relationships, lifecycle states, FHIR recommendations
fhir-data-model-design	docs/planning/fhir-data-model.md	FHIR spec: concrete resources, terminology bindings, resource relationships
digital-health-compliance-planning	docs/planning/compliance-brief.md	Compliance brief: privacy domains, consent requirements, audit controls

Read each file that exists. For any that are missing, note the gap and move on.

Then ask:

1. "Are there any planning documents saved elsewhere, or anything about the app not captured in the planning files?"

If no planning documents are found at all, ask the user to describe the app's core features, user types, and data needs so you can extract features directly.

---

Step 2: Confirm Platform and Backend

Identify the choices made during platform selection.

Ask:

1. "Which template did you clone — the React Native Template App or the Spezi Template Application for Apple Platforms?"
2. "Which backend are you using — Firebase, Medplum, or something else?"

Read the appropriate reference file based on the platform:

• React Native → read react-native-packages.md
• Apple-native → read apple-native-modules.md

---

Step 3: Extract Features

Parse the planning outputs into a list of discrete, buildable features. Each feature should be:

• Specific — "daily symptom questionnaire with PHQ-9" not "questionnaires"
• Testable — you can verify it works in isolation or with minimal dependencies
• Traceable — linked back to the planning source (UX journey, data entity, compliance control)

Common feature categories:

Category	Examples
Account	Sign-in, registration, profile management, password reset
Onboarding	Welcome screens, feature highlights, informed consent, permissions
Data collection	Questionnaires, surveys, daily check-ins, manual entry
Health data	HealthKit sync, vitals reading, wearable data
Scheduling	Task reminders, assessment windows, care plan activities
Communication	Chat with provider, AI coaching, secure messaging
Data management	Backend sync, offline storage, FHIR resource mapping
Compliance	Consent tracking, audit logging, data retention, access control
Engagement	Notifications, streaks, progress visualization

For each feature, note:

• Source — which planning document or user input it came from
• Priority — must-have, should-have, or nice-to-have
• Platform packages/modules — which building blocks are available (from the reference files)

Also extract separately:

• Data entities — if a health-data-model-planning or fhir-data-model-design document is available, list each data entity (e.g., Patient, Observation, QuestionnaireResponse) with its FHIR resource mapping. These feed the Data Model Integration table in the output document.
• Compliance controls — if a digital-health-compliance-planning document is available, list each required control (e.g., "audit log all PHI access", "collect informed consent before data collection", "enforce data retention policy"). These feed the Compliance Integration table in the output document.

---

Step 4: Map to Packages and Modules

For each extracted feature, identify which pre-built packages (React Native) or modules (Apple-native) can be used.

Use the reference files:

• react-native-packages.md — @spezivibe/account, @spezivibe/onboarding, @spezivibe/questionnaire, @spezivibe/scheduler, @spezivibe/chat, @spezivibe/firebase, @spezivibe/medplum
• apple-native-modules.md — SpeziAccount, SpeziOnboarding, SpeziQuestionnaire, SpeziScheduler, SpeziChat, SpeziHealthKit, SpeziFHIR, SpeziFirebaseAccount, SpeziFirestore, SpeziNotifications, SpeziViews

Check the reference file's Status field for each package before recommending it. Some packages (notably @spezivibe/healthkit) are not yet built and should be flagged as requiring custom implementation.

For features that have no matching package or module, note that they require custom implementation and estimate relative effort (small, medium, large).

---

Step 5: Sequence into Milestones

Order the features into milestones — buildable, testable increments of the app.

Read milestone-patterns.md to select a starting pattern based on the app archetype:

• Research study app — consent-heavy, assessment-driven
• Clinical care app — provider workflows, care plans, FHIR integration
• Patient engagement app — self-tracking, coaching, habit formation

Adapt the pattern to the actual features:

1. Remove milestones that do not apply
2. Reorder based on what is most important to the user
3. Split large milestones that cover too many features
4. Merge small milestones that are tightly coupled
5. Add milestones for features not in any pattern

Each milestone must have:

• Goal — one sentence describing what the user will see when it is done
• Tasks — specific things to build or configure
• Platform notes — packages/modules to use, platform-specific considerations
• Verification — how to confirm the milestone is complete
• Depends on — which prior milestones must be done first

Milestones should follow this general order:

1. Foundation — navigation, theming, project configuration
2. Account — authentication, profile setup
3. Onboarding — welcome flow, consent, permissions
4. Core features — the primary value of the app (data collection, health tracking, scheduling)
5. Communication — chat, messaging (if applicable)
6. Backend integration — data sync, FHIR mapping, server communication
7. Compliance — audit logging, consent tracking, data retention
8. Engagement — notifications, progress visualization, streaks
9. Polish — error handling, accessibility, offline support

---

Step 6: Produce the Implementation Plan

Generate the full implementation plan document using this format:

# Implementation Plan: [App Name]

> Generated by `app-build-planner`. Save as `docs/implementation-plan.md` in your project.

## Context

| Field | Value |
|-------|-------|
| App | [Name and one-line description] |
| Need statement | [From biodesign-needs-finding, or "Not available"] |
| Platform | [React Native / Apple-native] |
| Backend | [Firebase / Medplum / Other] |
| Study context | [Yes — brief description / No] |

## Planning Inputs

[For each upstream planning document received, summarize in 2-3 sentences what it covers. Note any planning areas that were not completed.]

## Feature List

| # | Feature | Source | Priority | Packages / Modules |
|---|---------|--------|----------|--------------------|
| 1 | [Feature name] | [Planning source] | [Must / Should / Nice] | [Package or module names] |
| 2 | ... | ... | ... | ... |

## Milestones

### Milestone 1: [Name]

**Goal:** [One sentence — what the user sees when this is done]

**Depends on:** [Nothing / Milestone N]

**Tasks:**
1. [Specific task]
2. [Specific task]
3. ...

**Platform notes:**
- [Package/module to use and how]
- [Platform-specific consideration]

**Verify:**
- [How to confirm this milestone works]

---

### Milestone 2: [Name]
...

### Milestone N: [Name]
...

## Data Model Integration

[Map each data entity from the planning phase to the milestone where it gets implemented.]

| Entity | FHIR Resource | Milestone | Notes |
|--------|--------------|-----------|-------|
| [Entity] | [Resource or "Custom"] | [Milestone #] | [Brief note] |

## Compliance Integration

[Map each compliance control to the milestone where it gets addressed.]

| Control | Milestone | How |
|---------|-----------|-----|
| [Control] | [Milestone #] | [Brief approach] |

## Open Questions

[List unresolved items that could affect implementation — for example:]
- [Unresolved backend or infrastructure choices]
- [Features marked "should-have" that need scope confirmation]
- [Missing planning inputs that could change milestone ordering]
- [Third-party integrations that need API access or credentials]

## Next Steps

Save this document as `docs/implementation-plan.md` in your project repository.

To start building, work through the milestones one at a time with your coding
agent. Each milestone is designed to be built and reviewed as a single focused
session. If your cloned repository has a local build skill, use that. Otherwise,
share this document as context and ask your agent to implement the first milestone.

---

Guardrails

• Do not generate application code. This skill produces a plan, not source code.
• Do not assume a backend unless the user has confirmed their choice. Ask.
• Do not skip missing inputs. If a planning area was not completed, note it as a gap and flag what the user might want to revisit.
• Keep milestones small and testable. Each milestone should produce a visible, verifiable change. If a milestone has more than 5-7 tasks, consider splitting it.
• Stay platform-aware but not platform-expert. Reference the correct packages and modules from the reference files but leave detailed implementation guidance to the repo-local build skill.
• Respect priority. Must-have features go into early milestones. Nice-to-have features go at the end and can be dropped without breaking the plan.

---

Checklist

Before delivering the implementation plan, verify:

• Every feature from the UX brief is represented in the feature list
• Every data entity from the data model is mapped to a milestone
• Every compliance control is assigned to a milestone
• Milestones are in dependency order — no milestone depends on a later one
• Each milestone has a clear goal, tasks, and verification criteria
• Platform packages or modules are identified for each feature that has one
• Custom implementation effort is noted for features without a matching package
• Missing planning inputs are flagged
• Open questions are listed
• The handoff instruction tells the user where to save the document