incremental-implementation

name	incremental-implementation
description	Delivers changes incrementally. Use when implementing any feature or change that touches more than one file. Use when you're about to write a large amount of code at once, or when a task feels too big to land in one step.
zh_description	用于incremental、实现，支持任务规划、执行、评审和验证。
version	1.0.0
author	addyosmani
source	github:addyosmani/agent-skills
source_url	https://github.com/addyosmani/agent-skills/blob/main/skills/incremental-implementation/SKILL.md
license	MIT
tags	["agent", "ai", "engineering", "incremental-implementation", "workflow"]
created_at	2026-07-27
updated_at	2026-07-27
quality	5
complexity	advanced
upstream_slug	incremental-implementation

Incremental Implementation

Overview

Build in thin vertical slices — implement one piece, test it, verify it, then expand. Avoid implementing an entire feature in one pass. Each increment should leave the system in a working, testable state. This is the execution discipline that makes large features manageable.

When to Use

• Implementing any multi-file change
• Building a new feature from a task breakdown
• Refactoring existing code
• Any time you're tempted to write more than ~100 lines before testing

When NOT to use: Single-file, single-function changes where the scope is already minimal.

The Increment Cycle

┌──────────────────────────────────────┐
│                                      │
│   Implement ──→ Test ──→ Verify ──┐  │
│       ▲                           │  │
│       └───── Commit ◄─────────────┘  │
│              │                       │
│              ▼                       │
│          Next slice                  │
│                                      │
└──────────────────────────────────────┘

For each slice:

1. Implement the smallest complete piece of functionality
2. Test — run the test suite (or write a test if none exists)
3. Verify — confirm the slice works as expected (tests pass, build succeeds, manual check)
4. Commit -- save your progress with a descriptive message (see git-workflow-and-versioning for atomic commit guidance)
5. Move to the next slice — carry forward, don't restart

Slicing Strategies

Vertical Slices (Preferred)

Build one complete path through the stack:

Slice 1: Create a task (DB + API + basic UI)
    → Tests pass, user can create a task via the UI

Slice 2: List tasks (query + API + UI)
    → Tests pass, user can see their tasks

Slice 3: Edit a task (update + API + UI)
    → Tests pass, user can modify tasks

Slice 4: Delete a task (delete + API + UI + confirmation)
    → Tests pass, full CRUD complete

Each slice delivers working end-to-end functionality.

Contract-First Slicing

When backend and frontend need to develop in parallel:

Slice 0: Define the API contract (types, interfaces, OpenAPI spec)
Slice 1a: Implement backend against the contract + API tests
Slice 1b: Implement frontend against mock data matching the contract
Slice 2: Integrate and test end-to-end

Risk-First Slicing

Tackle the riskiest or most uncertain piece first: