Effect v4 Code Review

Orchestrate a multi-agent review against Effect v4 ("effect-smol", the effect@4.0.0-beta.* line) best practices.

Effect v4 is a structural rewrite. Services, errors, Cause, and Schema all changed shape. This skill checks that v4 code follows v4 conventions — it does not hunt for leftover v3 APIs. If the codebase is on Effect v3, use the effect-review skill instead.

Step 0: Determine Review Mode

The skill has two modes:

• PR mode — review only the files changed on the current branch / PR.
• Repo mode — review the entire repository, fanning out across a large number of subagents.

Pick the mode from the user's request: