Effect Service Design

Treat a service as an authority seam: a cohesive capability whose requirements should propagate through Effect context. An Effect service module owns the service contract, construction, production Layer, and any honest reusable test implementation that belong to the same capability.

1. Establish the local rules

Read the nearest AGENTS.md, architecture docs, coding standards, project Effect guidance, pinned Effect version/source, and relevant vendored examples. Prefer current project-compatible patterns over remembered APIs.

Complete when: the governing files and pinned source examples have been read and recorded for use in later decisions.

2. Select the branch

• Design branch: for a new service or a focused redesign, bound the capability, trace one caller-visible operation to every effect, then continue below.
• Audit branch: for a codebase, package, feature slice, or diff, read and follow references/AUDIT.md, applying the rules below to every candidate it finds.

Complete when: one branch is selected, its scope is bounded, and the caller-visible operations in scope are named.

3. Apply the service test