planning-and-task-breakdown

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Translated

Use when you have a spec or clear requirements and need to break work into implementable tasks. Use when a task feels too large to start, when you need to estimate scope, or when parallel work is possible.

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Sourceaddyosmani/agent-skills

Added on2026-03-14

NPX Install

npx skill4agent add addyosmani/agent-skills planning-and-task-breakdown

SKILL.md Content

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Planning and Task Breakdown

Overview

Decompose work into small, verifiable tasks with explicit acceptance criteria. Good task breakdown is the difference between an agent that completes work reliably and one that produces a tangled mess. Every task should be small enough to implement, test, and verify in a single focused session.

When to Use

You have a spec and need to break it into implementable units
A task feels too large or vague to start
Work needs to be parallelized across multiple agents or sessions
You need to communicate scope to a human
The implementation order isn't obvious

When NOT to use: Single-file changes with obvious scope, or when the spec already contains well-defined tasks.

The Planning Process

Step 1: Enter Plan Mode

Before writing any code, operate in read-only mode:

Read the spec and relevant codebase sections
Identify existing patterns and conventions
Map dependencies between components
Note risks and unknowns

Do NOT write code during planning. The output is a plan document, not implementation.

Step 2: Identify the Dependency Graph

Map what depends on what:

Database schema
    │
    ├── API models/types
    │       │
    │       ├── API endpoints
    │       │       │
    │       │       └── Frontend API client
    │       │               │
    │       │               └── UI components
    │       │
    │       └── Validation logic
    │
    └── Seed data / migrations

Implementation order follows the dependency graph bottom-up: build foundations first.

Step 3: Slice Vertically

Instead of building all the database, then all the API, then all the UI — build one complete feature path at a time:

Bad (horizontal slicing):

Task 1: Build entire database schema
Task 2: Build all API endpoints
Task 3: Build all UI components
Task 4: Connect everything

Good (vertical slicing):

Task 1: User can create an account (schema + API + UI for registration)
Task 2: User can log in (auth schema + API + UI for login)
Task 3: User can create a task (task schema + API + UI for creation)
Task 4: User can view task list (query + API + UI for list view)

Each vertical slice delivers working, testable functionality.

Step 4: Write Tasks

Each task follows this structure:

markdown

## Task [N]: [Short descriptive title]

**Description:** One paragraph explaining what this task accomplishes.

**Acceptance criteria:**
- [ ] [Specific, testable condition]
- [ ] [Specific, testable condition]

**Verification:**
- [ ] Tests pass: `npm test -- --grep "feature-name"`
- [ ] Build succeeds: `npm run build`
- [ ] Manual check: [description of what to verify]

**Dependencies:** [Task numbers this depends on, or "None"]

**Files likely touched:**
- `src/path/to/file.ts`
- `tests/path/to/test.ts`

**Estimated scope:** [Small: 1-2 files | Medium: 3-5 files | Large: 5+ files]

Step 5: Order and Checkpoint

Arrange tasks so that:

Dependencies are satisfied (build foundation first)
Each task leaves the system in a working state
Verification checkpoints occur after every 2-3 tasks
High-risk tasks are early (fail fast)

Add explicit checkpoints:

markdown

## Checkpoint: After Tasks 1-3
- [ ] All tests pass
- [ ] Application builds without errors
- [ ] Core user flow works end-to-end
- [ ] Review with human before proceeding

Task Sizing Guidelines

Size	Files	Scope	Example
XS	1	Single function or config change	Add a validation rule
S	1-2	One component or endpoint	Add a new API endpoint
M	3-5	One feature slice	User registration flow
L	5-8	Multi-component feature	Search with filtering and pagination
XL	8+	Too large — break it down further	—

If a task is L or larger, it should be broken into smaller tasks. An agent performs best on S and M tasks.

Plan Document Template

markdown

# Implementation Plan: [Feature/Project Name]

## Overview
[One paragraph summary of what we're building]

## Architecture Decisions
- [Key decision 1 and rationale]
- [Key decision 2 and rationale]

## Task List

### Phase 1: Foundation
- [ ] Task 1: ...
- [ ] Task 2: ...

### Checkpoint: Foundation
- [ ] Tests pass, builds clean

### Phase 2: Core Features
- [ ] Task 3: ...
- [ ] Task 4: ...

### Checkpoint: Core Features
- [ ] End-to-end flow works

### Phase 3: Polish
- [ ] Task 5: ...
- [ ] Task 6: ...

### Checkpoint: Complete
- [ ] All acceptance criteria met
- [ ] Ready for review

## Risks and Mitigations
| Risk | Impact | Mitigation |
|------|--------|------------|
| [Risk] | [High/Med/Low] | [Strategy] |

## Open Questions
- [Question needing human input]

Parallelization Opportunities

When multiple agents or sessions are available:

Safe to parallelize: Independent feature slices, tests for already-implemented features, documentation
Must be sequential: Database migrations, shared state changes, dependency chains
Needs coordination: Features that share an API contract (define the contract first, then parallelize)

Common Rationalizations

Rationalization	Reality
"I'll figure it out as I go"	That's how you end up with a tangled mess and rework. 10 minutes of planning saves hours.
"The tasks are obvious"	Write them down anyway. Explicit tasks surface hidden dependencies and forgotten edge cases.
"Planning is overhead"	Planning is the task. Implementation without a plan is just typing.
"I can hold it all in my head"	Context windows are finite. Written plans survive session boundaries and compaction.

Red Flags

Starting implementation without a written task list
Tasks that say "implement the feature" without acceptance criteria
No verification steps in the plan
All tasks are XL-sized
No checkpoints between tasks
Dependency order isn't considered

Verification

Before starting implementation, confirm:

Every task has acceptance criteria
Every task has a verification step
Task dependencies are identified and ordered correctly
No task touches more than ~5 files
Checkpoints exist between major phases
The human has reviewed and approved the plan

planning-and-task-breakdown

NPX Install

Tags

SKILL.md Content

Planning and Task Breakdown

Overview

When to Use

The Planning Process

Step 1: Enter Plan Mode

Step 2: Identify the Dependency Graph

Step 3: Slice Vertically

Step 4: Write Tasks

Step 5: Order and Checkpoint

Task Sizing Guidelines

Plan Document Template

Parallelization Opportunities

Common Rationalizations

Red Flags

Verification