Developers struggle with microservice sizing, oscillating between overly granular services that create network chaos and monolithic ones that stifle agility. The core issue isn't size but boundaries. A well-defined boundary requires a clear contract, explicit dependencies, and internal implementation freedom. Most designs fail by drawing boundaries based on technical layers or team structure instead of actual component contracts.

A new approach, Slices, defines deployable units through a single interface annotation. The `@Slice` annotation processor handles all boilerplate: factories, dependency wiring, and deployment metadata. This creates a clean contract where methods define requests and responses, types are explicit, and async is default. Implementation details stay hidden, allowing changes without breaking callers.

Slices run on the Aether distributed runtime, which manages service discovery and communication transparently. Forge provides a local development environment for testing with load and chaos. The same code runs in three modes: Ember for local dev, Forge for stress-testing, and Aether for production. This eliminates environment-specific code and simplifies the development workflow from coding to deployment.