Effect TypeScript

Use Effect for application I/O so failures, dependencies, and resource lifetimes are explicit. Adapt a Promise-based driver or SDK once at its boundary; keep internal operations in Effect. Run Effects at the caller or runtime boundary that requires a Promise or starts the program. Pure transformations remain plain TypeScript.

Follow codebase-design for the shared readability rules and examples. Keep related queries, bindings, decoding, and private helpers with their adapter; extract only when it hides complexity or enables useful reuse. Operations own completion, errors, and cleanup, or explicitly hand that responsibility to their caller.

This skill adapts Effect guidance to darkmatter conventions: use Bun commands instead of pnpm for darkmatter projects, and prefer Alchemy for deployable infrastructure.

Bootstrap

If effect-solutions is not on in your $PATH, install it: bun add -g effect-solutions@latest. Prefer the repository's pinned Effect source or installed package for API details; use a version-matching checkout when neither is available.

For new Darkmatter TypeScript repos, align dependencies with the darkmatter/template root catalog. Use Effect 4, @effect/tsgo, @effect/vitest, @effect/platform-bun, and effect-solutions; prefer the Effect agent APIs (effect/unstable/ai) before inventing agent loop contracts.

Guidelines