Task Decomposition Skill
Purpose
This skill provides expertise in decomposing specifications into executable, dependency-ordered implementation tasks. It transforms structured requirements and user stories into a concrete work plan that developers can follow sequentially or in parallel. The output is a tasks.md file with numbered tasks, dependency annotations, and full traceability back to the specification.
When It Activates
The skill is triggered when the conversation involves:
- •Breaking down a specification into implementation tasks
- •Creating or updating a
tasks.mdfile - •Discussing work breakdown, task ordering, or dependency analysis
- •Planning implementation phases or sprint work
- •Identifying parallelizable work streams
Capabilities
1. Phase-Based Task Ordering
Tasks are organized into five sequential phases:
| Phase | Purpose | Examples |
|---|---|---|
| Setup | Project scaffolding, tooling, configuration | Init repo, install deps, configure linter |
| Foundation | Core infrastructure and data layer | Database schema, base models, auth setup |
| Stories | Feature implementation per user story | Implement US1, US2, US3 endpoints and UI |
| Integration | Cross-feature wiring, E2E flows | API integration, state management, routing |
| Finalization | Quality assurance, polish, deployment prep | Testing, docs, CI/CD, performance tuning |
Tasks within each phase are ordered by dependency. A later phase never starts before its prerequisites in earlier phases are complete.
2. Task Format
Every task follows this standardized format:
- [ ] T001 [P] [US1] path/to/file.ts -- Description (S) [Spec FR-001]
Where:
- •
T001-- Unique task identifier, zero-padded and sequential - •
[P]-- Parallelizable marker (present only if the task can run concurrently with others) - •
[US1]-- User story reference linking to the specification - •
path/to/file.ts-- Primary file or directory affected - •
Description-- Concise action description starting with a verb - •
(S)-- Size estimate:(S)small,(M)medium,(L)large - •
[Spec FR-001]-- Traceability reference back to a specific requirement section
3. Dependency Detection
The skill analyzes tasks to detect and annotate dependencies:
- •Explicit dependencies: Task B requires output of Task A (e.g., schema before migration)
- •Implicit dependencies: Shared file or module modifications that must be sequenced
- •Blocking dependencies: Tasks that gate an entire phase transition
Dependencies are expressed as depends: T001, T003 annotations when non-obvious ordering exists.
4. Parallel Task Identification
Tasks that share no dependencies are marked with the [P] flag, indicating they can be executed concurrently. The skill groups parallelizable tasks together within each phase to maximize throughput.
5. Coverage Validation
After generating the task list, the skill validates coverage:
- •Every
FR-XXXin the specification maps to at least one task - •Every
NFR-XXXhas a corresponding task or is addressed by a cross-cutting task - •Every user story (
US1,US2, ...) appears in at least one task's[USx]tag
6. Gap Flagging
When coverage validation detects missing mappings, the skill inserts explicit gap markers:
- [ ] T015 [Gap] -- No task covers FR-012 (payment retry logic) [Spec FR-012]
Gap markers are clearly labeled with [Gap] so they can be identified and resolved before implementation begins.
Methodology
The decomposition process follows these steps:
- •Parse Specification: Read
spec.mdto extract all FR, NFR, user stories, data model entities, and API contracts. - •Identify Work Units: Map each requirement to one or more concrete implementation actions (file creation, function implementation, configuration change).
- •Assign Phases: Place each work unit into the appropriate phase (Setup, Foundation, Stories, Integration, Finalization).
- •Detect Dependencies: Analyze inter-task relationships and establish ordering constraints.
- •Mark Parallelism: Flag tasks with no dependencies as parallelizable
[P]. - •Estimate Sizes: Assign size estimates based on scope and complexity.
- •Validate Coverage: Ensure every requirement is covered by at least one task.
- •Flag Gaps: Insert
[Gap]markers for any uncovered requirements.
References
For detailed format specifications, dependency patterns, and phase ordering rules, consult:
- •
references/task-format.md-- Full task format specification with examples - •
references/dependency-patterns.md-- Common dependency patterns and resolution strategies - •
references/phase-ordering.md-- Phase definitions, transition criteria, and ordering rules