// 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.
| 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. |
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 NOT to use: Single-file, single-function changes where the scope is already minimal.
┌──────────────────────────────────────┐
│ │
│ Implement ──→ Test ──→ Verify ──┐ │
│ ▲ │ │
│ └───── Commit ◄─────────────┘ │
│ │ │
│ ▼ │
│ Next slice │
│ │
└──────────────────────────────────────┘
For each slice:
git-workflow-and-versioning for atomic commit guidance)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.
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
Tackle the riskiest or most uncertain piece first:
Slice 1: Prove the WebSocket connection works (highest risk)
Slice 2: Build real-time task updates on the proven connection
Slice 3: Add offline support and reconnection
If Slice 1 fails, you discover it before investing in Slices 2 and 3.
Before writing any code, ask: "What is the simplest thing that could work?"
After writing code, review it against these checks:
SIMPLICITY CHECK:
✗ Generic EventBus with middleware pipeline for one notification
✓ Simple function call
✗ Abstract factory pattern for two similar components
✓ Two straightforward components with shared utilities
✗ Config-driven form builder for three forms
✓ Three form components
Three similar lines of code is better than a premature abstraction. Implement the naive, obviously-correct version first. Optimize only after correctness is proven with tests.
Touch only what the task requires.
Do NOT:
If you notice something worth improving outside your task scope, note it — don't fix it:
NOTICED BUT NOT TOUCHING:
- src/utils/format.ts has an unused import (unrelated to this task)
- The auth middleware could use better error messages (separate task)
→ Want me to create tasks for these?
Each increment changes one logical thing. Don't mix concerns:
Bad: One commit that adds a new component, refactors an existing one, and updates the build config.
Good: Three separate commits — one for each change.
After each increment, the project must build and existing tests must pass. Don't leave the codebase in a broken state between slices.
If a feature isn't ready for users but you need to merge increments:
// Feature flag for work-in-progress
const ENABLE_TASK_SHARING = process.env.FEATURE_TASK_SHARING === 'true';
if (ENABLE_TASK_SHARING) {
// New sharing UI
}
This lets you merge small increments to the main branch without exposing incomplete work.
New code should default to safe, conservative behavior:
// Safe: disabled by default, opt-in
export function createTask(data: TaskInput, options?: { notify?: boolean }) {
const shouldNotify = options?.notify ?? false;
// ...
}
Each increment should be independently revertable:
When directing an agent to implement incrementally:
"Let's implement Task 3 from the plan.
Start with just the database schema change and the API endpoint.
Don't touch the UI yet — we'll do that in the next increment.
After implementing, run `npm test` and `npm run build` to verify
nothing is broken."
Be explicit about what's in scope and what's NOT in scope for each increment.
After each increment, verify:
npm test)npm run build)npx tsc --noEmit)npm run lint)Note: Run each verification command after a change that could affect it. After a successful run, don't repeat the same command unless the code has changed since — re-running on unchanged code adds no information.
| Rationalization | Reality |
|---|---|
| "I'll test it all at the end" | Bugs compound. A bug in Slice 1 makes Slices 2-5 wrong. Test each slice. |
| "It's faster to do it all at once" | It feels faster until something breaks and you can't find which of 500 changed lines caused it. |
| "These changes are too small to commit separately" | Small commits are free. Large commits hide bugs and make rollbacks painful. |
| "I'll add the feature flag later" | If the feature isn't complete, it shouldn't be user-visible. Add the flag now. |
| "This refactor is small enough to include" | Refactors mixed with features make both harder to review and debug. Separate them. |
| "Let me run the build command again just to be sure" | After a successful run, repeating the same command adds nothing unless the code has changed since. Run it again after subsequent edits, not as reassurance. |
After completing all increments for a task:
Extracts what the user actually wants instead of what they think they should want. Achieves this through one-question-at-a-time interview until ~95% confidence about the underlying intent. Use when an ask is underspecified ("build me X" without "for whom" or "why now"), when the user explicitly invokes ("interview me", "grill me", "are we sure?", "stress-test my thinking"), or when you catch yourself silently filling in ambiguous requirements before any plan, spec, or code exists.
Discovers and invokes agent skills. Use when starting a session or when you need to discover which skill applies to the current task. This is the meta-skill that governs how all other skills are discovered and invoked.
Tests in real browsers via Chrome DevTools MCP. Use when building or debugging anything that runs in a browser. Use when you need to inspect the DOM, capture console errors, analyze network requests, profile performance, or verify visual output with real runtime data. Requires the chrome-devtools MCP server to be configured.
Refines raw ideas into sharp, actionable concepts through structured divergent and convergent thinking. Use when an idea is still vague, when you need to stress-test assumptions before committing to a plan, or when you want to expand options before converging on one. Triggers on "ideate", "refine this idea", or "stress-test my plan".
Creates specs before coding. Use when starting a new project, feature, or significant change and no specification exists yet. Use when requirements are unclear, ambiguous, or only exist as a vague idea.
Subjects every non-trivial decision to a fresh-context adversarial review before it stands. Use when correctness matters more than speed, when working in unfamiliar code, when stakes are high (production, security-sensitive logic, irreversible operations), or any time a confident output would be cheaper to verify now than to debug later.