By name: sdd-plan description: > SDD step 3. Read feature.md and produce a detailed implementation plan.md tailored to the project's tech stack and architecture. Use after /sdd-feature has produced feature.md.
SDD: Implementation Planning
You are acting as a senior software engineer creating a precise, actionable implementation plan.
Pre-conditions
Verify both files exist before proceeding:
feature.md— the feature spec (if missing, tell the user to run/sdd-featurefirst)docs/project.md— project context
Process
1. Read Both Files
Read feature.md and docs/project.md in full.
2. Identify the Tech Stack
From docs/project.md, note:
- Primary language and framework
- Build tool and compile/test commands
- Database and data access layer
- Messaging systems
- Testing frameworks
- Any architecture patterns (e.g., Hexagonal, DDD, Layered)
3. Produce plan.md
Create plan.md in the project root with this structure:
# Implementation Plan: <Feature Name>
## Overview
Brief description of the implementation approach.
## Architecture Decisions
- Key design choices and their rationale
- Patterns to follow (aligned with docs/project.md)
## Implementation Steps
### Step 1: <Database/Schema Changes>
- [ ] Create/alter table: `...`
- [ ] Add migration file: `...`
- Files to create/modify: ...
### Step 2: <Domain Layer>
- [ ] Create entity / model: `...`
- [ ] Create value objects: `...`
- [ ] Define repository / data access interface: `...`
- Files: ...
### Step 3: <Application/Service Layer>
- [ ] Create use case / service: `...`
- [ ] Define request/response objects / command objects: `...`
- Files: ...
### Step 4: <Infrastructure/Adapter Layer>
- [ ] Implement repository / data access: `...`
- [ ] External integrations: `...`
- Files: ...
### Step 5: <API / Presentation Layer>
- [ ] Controller / handler / route: `...`
- [ ] Request/response models: `...`
- [ ] API documentation annotations: `...`
- Files: ...
### Step 6: <Tests>
- [ ] Unit tests: `...`
- [ ] Integration tests: `...`
- [ ] API / end-to-end tests: `...`
- Files: ...
## Acceptance Criteria Mapping
| AC | Verified By |
|----|-------------|
| AC-01: ... | `<TestClass#testMethod>` |
| AC-02: ... | `<TestClass#testMethod>` |
## Risks & Mitigations
- Risk: ... → Mitigation: ...
## Estimated Complexity
Low / Medium / High — brief justification
After writing the file, present a summary of the plan and ask the user to approve before proceeding to /sdd-implement.