---
name: lisa-task-decomposition
description: "Methodology for breaking work into ordered tasks. Cross-repo source PRDs and coordination containers stay cross-repo; each buildable leaf task gets a single-repo scope, acceptance criteria, verification type, dependencies, and skills required."
---

# Task Decomposition

Break work into ordered, well-scoped tasks that can be independently implemented and verified.

## Decomposition Process

### 1. Identify Units of Work

- Break the work into the smallest units that are independently valuable
- Each unit should produce a verifiable outcome (a passing test, a working endpoint, observable behavior)
- Avoid tasks that are too large to complete in a single session
- Avoid tasks that are too small to be meaningful (e.g., "add an import statement")

### 1.5. Preserve Cross-Repo Containers, Split Leaf Work by Repository

Start from the right shape:

- A source PRD may span multiple repositories.
- Coordination containers may also span multiple repositories.
- Buildable leaf work units must be implementable inside exactly one repository.

That last point is a hard invariant — downstream validators (`jira-validate-ticket`, `github-validate-issue`, `linear-validate-issue`) gate writes on it, so a cross-repo leaf will fail to be created.

Apply this rule by layer:

| Layer | Repo scope |
|-------|------------|
| **PRD / source initiative** | MAY span repos — it describes the full initiative |
| **Epic, Story, Spike** | MAY span repos — these are coordination containers |
| **Task, Bug, Sub-task, Improvement** | MUST name exactly one repo — these are buildable leaf work units |

If a candidate work unit naturally touches multiple repos (e.g., "add field to backend API and consume it in mobile app"), do not write it as one ticket. Instead:

1. Split it into one work unit per repo (e.g., `[backend-api] Add field to /users endpoint`, `[mobile-app] Display new field on profile screen`).
2. Group the per-repo units under a single parent Story (or Epic, if the parent Story already exists). The parent stays cross-repo; the children do not.
3. Encode the order via `Dependencies` in step 4 — typically the producing repo (backend) blocks the consuming repo (frontend/mobile).
4. Tag each work unit with `[repo-name]` as a summary prefix so the repo is visible in tracker lists at a glance.

Reject any work unit whose acceptance criteria reference behavior in a different repo from the one it's scoped to. If you find yourself writing "and the frontend should also...", that's a signal to split.

This is the **decomposition-time** strategy (greenfield — you are creating the tickets now, so a cross-repo PRD can stay whole, its Epic/Story/Spike containers can stay cross-repo, and a parent Story + per-repo children is the natural shape). It is distinct from the **work-time** strategy in the `repo-scope-split` rule, which applies when an agent picks up an *already-existing leaf ticket* to implement and discovers it spans repos: there it narrows the original in place and spins off sibling work units rather than introducing a new parent. Use the phase-appropriate one; do not mix them.

### 2. Define Acceptance Criteria

For each task, define what "done" looks like:

- Be specific and measurable -- avoid vague criteria like "works correctly"
- Include both positive cases (what should work) and negative cases (what should be rejected)
- Reference exact behavior: error messages, status codes, output format, performance thresholds
- If a task modifies existing behavior, state both the before and after

For a **frontend task** -- one that adds or changes a user-observable surface -- the `bdd-e2e-coverage` rule makes two further criteria mandatory on the item itself, never left implied: (a) the Gherkin scenarios it adds or changes in the project's behavior contract, with their stable IDs and required platforms, and (b) aligned e2e automation in the project's configured runner for each of those platforms, with the coverage gate passing and the matrix and burndown regenerated. Carry both into the item's Validation Journey. A project with no behavior contract yet does not get an exemption -- the first such task carries the bootstrap scaffolding as a deliverable, scoped to its own behavior (cite the rule; do not restate its bootstrap steps).

For a task that adds or changes **persistent state** -- anything the system writes that outlives the process that wrote it, including identity-provider objects, object storage, search indexes, queues, caches and derived views, not only rows -- the `reset-seed-coverage` rule makes two further criteria mandatory on the item itself, never left implied: (a) every entity it introduces or changes is classified in the project's state contract with a reason and an owner, and (b) anything classified `fixture-owned` has a declared ownership predicate and an actual sweep, with the state-classification check passing. Carry both into the item's Validation Journey. A project with no state contract yet does not get an exemption -- the first such task carries the bootstrap scaffolding as a deliverable, scoped to its own state (cite the rule; do not restate its bootstrap steps).

### 3. Assign Verification Type

Each task must have a verification method. Choose the most appropriate:

| Verification Type | When to Use |
|-------------------|-------------|
| **Unit test** | Pure logic, data transformations, utility functions |
| **Integration test** | Cross-module interactions, database operations, API contracts |
| **E2E test** | User-facing workflows, multi-service interactions |
| **Manual verification** | UI/UX behavior, visual correctness, one-time infrastructure changes |
| **Build verification** | Compilation, type checking, linting, bundle size |
| **Deploy verification** | Service health checks, smoke tests, monitoring dashboards |

### 4. Map Dependencies

- Identify which tasks must complete before others can start
- Order tasks so that each builds on a stable foundation
- Prefer independent tasks that can run in parallel where possible
- Flag external dependencies (other teams, services, permissions, data) that may block progress

### 4.5. Classify Any New Material Dependency

Step 4 maps dependencies *between tasks*. This step covers third-party
dependencies a task proposes to **add**.

A dependency is **material** if its failure, disappearance, or bad update would
break something a user can see, or would cost real time to replace. If a work
unit proposes adding one, the work unit must, before it is buildable:

1. **Name its trust class** — exactly one of: mature ecosystem primitive,
   fast-moving standard implementation, build/development tool, runtime-critical
   service client, thin wrapper suitable for in-house ownership, or
   temporary/experimental dependency. See the `dependency-trust-classes` rule
   for what each class means and why it is trusted.
2. **State the class's required evidence** — the detection evidence that class
   demands, and whether product/human ratification is required before the work
   starts. Runtime-critical service clients and expiry extensions on temporary
   dependencies always require ratification; a work unit that needs it and does
   not say so is not ready.
3. **Include updating `.lisa/DEPENDENCY_DECISIONS.md`** in its acceptance
   criteria, so the record entry lands in the same change as the dependency.

If nobody can pick a class, that is the finding — resolve it before accepting
the work unit, not after the package is installed.

### 4.6. Inherit the Confidence-Rebuild Kit When Ownership Moves In-House

Step 4.5 covers dependencies a task proposes to **add**. This step covers
dependencies a task proposes to **remove, replace, or internalize** — vendor,
fork-and-maintain, or reimplement ourselves.

When ownership moves in-house, the risk stops being "do we trust upstream" and
becomes "did we prove we rebuilt the capability." A work unit that moves a
material dependency in-house **inherits all seven acceptance criteria** of the
`dependency-internalization-kit` rule, each written as an acceptance criterion
of the work unit:

1. **Real corpus** — did we test it on real inputs, not toy examples?
2. **Conformance fixtures** — does the new code do what the dependency did?
3. **Negative fixtures** — does it still reject what it should reject?
4. **Coverage as a gap detector** — what behavior is still untested?
5. **Provenance and license review** — where did this code come from, and are we
   allowed to use it?
6. **Migration and update plan** — how do existing call sites move, and how does
   the new code stay current?
7. **Rollback or replacement criteria** — what would make us go back, and to
   what?

The only way out is an **explicit non-material justification** written into the
work unit — one reviewable sentence saying why this dependency's failure or
disappearance breaks nothing a user can see and costs no real time to replace.
Silence is not a justification.

**Do not over-apply the kit.** A routine version bump of a trusted dependency
**within its existing trust class** does not move ownership, so it does not
inherit the kit — its bar is that trust class's own detection evidence and
cadence. The same is true of swapping one third-party dependency for another,
which moves trust to a different upstream rather than in-house. Add the kit only
when ownership moves in-house; the exception is a bump taken *as* a fork or
declined *in favor of* owning the code, which is an internalization regardless of
how the ticket is titled.

### 5. Determine Execution Order

- Place foundational tasks first (types, schemas, interfaces, shared utilities)
- Follow with implementation tasks (business logic, handlers, services)
- Then integration tasks (wiring, configuration, API routes)
- Finish with verification tasks (test suites, documentation, cleanup)

### 6. Assign Required Skills

Map each task to the skills needed to complete it. This enables delegation to specialized agents or helps identify what expertise is required.

## Output Format

```
## Task Breakdown

### Task 1: [[repo-name] imperative description]
- **Repository:** [single repo name, or N/A for Epic/Story/Spike]
- **Acceptance criteria:**
  - [specific, measurable criterion]
  - [specific, measurable criterion]
- **Verification:** [type] -- [how to verify]
- **Dependencies:** [none | task IDs that must complete first]
- **Skills:** [list of skills needed]

### Task 2: [[repo-name] imperative description]
- **Repository:** [single repo name, or N/A for Epic/Story/Spike]
- **Acceptance criteria:**
  - [specific, measurable criterion]
- **Verification:** [type] -- [how to verify]
- **Dependencies:** [Task 1]
- **Skills:** [list of skills needed]

### Execution Order
1. [Task 1, Task 3] (parallel -- no dependencies)
2. [Task 2] (depends on Task 1)
3. [Task 4] (depends on Task 2, Task 3)

### External Dependencies
- [dependency] -- [who owns it] -- [current status]
```

## Rules

- Every task must have at least one acceptance criterion that can be empirically verified
- Do not create tasks that cannot be verified -- if you cannot define how to prove it is done, the task is not well-scoped
- Every Task / Bug / Sub-task / Improvement is scoped to exactly one repo -- if the work spans repos, split into per-repo work units under a shared parent Story (see step 1.5)
- Any task proposing a new material dependency names its trust class, states that class's required evidence and whether human ratification is needed, and updates `.lisa/DEPENDENCY_DECISIONS.md` in the same change (see step 4.5) -- a proposed material dependency with no named class is not ready to build
- Any task removing, replacing, or internalizing a material dependency carries all seven confidence-rebuild kit criteria -- corpus, conformance, negative fixtures, coverage-as-gap-detector, provenance/license, migration/update plan, and rollback criteria (see step 4.6) -- unless it explicitly justifies why the dependency is non-material; a within-trust-class version bump does not carry the kit
- Keep tasks ordered so that no task references work that has not been completed by a prior task
- Flag any task that requires access, permissions, or external input not yet available
- Prefer more small tasks over fewer large tasks -- smaller tasks are easier to verify and less risky to fail
- Do not create placeholder or "TODO" tasks -- every task should describe concrete work
