# Extract a shared module into its own package

Code copied or reached into across boundaries, extracted into a package with its own tests and entry point.

Category: Architecture and boundaries
Source: https://letsship.ai/use-cases/extract-a-shared-module-into-a-package
Published: 2026-08-25

## Goal

Extract a shared module into its own package with its own tests and public entry point.

## Acceptance criteria

- The package builds and tests on its own
- Consumers import only the public entry point
- No consumer reaches into the package internals
- The extraction changes no behaviour

## What lands as proof

A standalone build and test run for the new package, plus consumers passing against its public surface only.

## Prompt

Copy this to an agent to open the ticket:

```text
Create a Linear issue in my team and assign it to the SHIP agent.

Title: Extract {module} into a package

Description: Extract a shared module into its own package with its own tests and public entry point.

Acceptance criteria:
- The package builds and tests on its own
- Consumers import only the public entry point
- No consumer reaches into the package internals
- The extraction changes no behaviour

Before you create the issue, find code in this repository that several places reach into across boundaries and replace {module} with it.
```

## Questions

### What does the agent actually change?

The ticket is scoped to one outcome: extract a shared module into its own package with its own tests and public entry point. Work that serves that outcome is in scope, and anything outside it is left for a separate ticket, so the pull request stays reviewable.

### How do I know the work is done?

The pull request carries the evidence, not only the diff. Here that means package builds standalone, consumers import the entry point only, so a reviewer can confirm the result without reproducing the work locally.

### How much oversight does this need?

The run stops once the plan is written. Somebody reads the approach and approves it before any code exists, which is the cheapest moment to redirect the work.