Ticking time bombs

The problem

You open a package and find it importing half the project: persistence, messaging, HTTP, configuration, caching. Any one of those dependencies can force work here. The package may look like a handy coordinator, but it is juggling too many contracts at once. That is the time bomb: the next dependency change has far too many ways to land on your desk.

Why it matters

High fan-out gives a package a lot to keep up with. High Instability tells you that outgoing dependencies dominate its total coupling. Put those together and you get a useful shortlist of packages stretched across a lot of dependency seams. Simplify them now and the next library, service, or internal API change has fewer places to catch you.

Where to start

Begin with Topology.

Step by step

1. Turn on the Instability heatmap.

   Open Topology and activate Instability. Red means outgoing dependencies dominate the package's total coupling. It does not mean the code changes frequently.

2. Raise the Fan-out threshold.

   The Workflow Wizard starts at the model's 75th percentile. Enable Hide isolated as well, leaving the connected packages that depend on more of the model than most.

3. Inspect what each red package is coordinating.

   Open the Metrics tab and inspect its incoming and outgoing relationships. Is this a focused coordinator with a clear job, or has one package become the place where unrelated responsibilities pile up?

4. Cut down the number of seams.

   Remove dependencies you no longer need, split overloaded orchestration, or put a narrow adapter around a contract that changes independently. Add focused tests around the dependency seams you keep.

Interpreting results

This workflow is about outward dependency exposure, not change history. A red package with high fan-out depends on many other packages, and those outgoing relationships dominate its coupling profile. That gives you a direct place to simplify responsibilities and protect integration seams before the next dependency change turns into regression work.

Export & share

Use Snapshot as PNG on the focused Topology view when you want to walk through the dependency-heavy packages with the team. Keep the Instability heatmap visible so the outward coupling pattern is clear.