bun

name	bun
description	Router skill for Bun 1.3.13 in dean-stack — pins the runtime via `packageManager` and dispatches to a sub-skill (runtime, test, package manager) based on the question. Triggers on: bun, bun 1.3.13, packageManager, which bun, bun overview.
license	MIT

Entry point for any Bun-shaped question in dean-stack. Bun 1.3.13 is the only allowed runtime/toolchain for this repo and is pinned via the root packageManager field.

When to invoke

• The user types bun with no further specifier and you need to route them.
• The user asks "which Bun skill," "Bun overview," or how Bun is installed/pinned for this repo.
• A question mixes runtime + test + install concerns and the right sub-skill is ambiguous — pick after reading the patterns table below.

Owns

Entry point that routes Bun questions to the right sub-skill (runtime, test runner, package manager) and pins Bun 1.3.13 via packageManager.

Defers to

• bun-runtime — anything about executing scripts (Bun.serve, Bun.file, Bun.$, bunx, runtime flags).
• bun-test — anything about unit tests (bun test, bun:test matchers, mocks, coverage, watch).
• bun-package-manager — anything about installing/adding/removing deps, the lockfile, workspaces, or overrides.
• turborepo — for which task runs when (bun run check ordering, dependsOn); Bun is the executor, Turbo is the scheduler.

Dean-stack rules

• Pillar 4 (CLI-gate-first) means: every script in package.json is invoked as bun run <name> and must be reachable through Turbo — no direct npx/pnpm/npm invocations slip in.
• Pillar 3 (IDB-first state) is unaffected at the Bun layer (state lives in the browser), but Bun is what runs the migration unit tests in bun test.
• The packageManager pin is load-bearing: a contributor on a different Bun version will get reproducible installs only if this field is honored by corepack/CI.

Patterns

Pin Bun via packageManager

// package.json (repo root)
{
  "packageManager": "bun@1.3.13",
  "engines": { "bun": ">=1.3.13" }
}

The pin is the single source of truth — no .bun-version, no Volta entry. CI reads packageManager and installs the matching Bun.

Routing table

Question shape	Sub-skill
"How do I write a unit test for an atom reducer?"	bun-test
"Add idb to the web app"	bun-package-manager
"Run a script that shells out to git"	bun-runtime
"Why is bun install slow in CI?"	bun-package-manager
"Cap test runner at 1 thread for IDB"	bun-test
"Read a JSON file in a build script"	bun-runtime

One Bun, three roles

bun install           # bun-package-manager
bun run check         # bun-runtime executes the script Turbo orchestrates
bun test app/state    # bun-test

Each command lives in a different sub-skill; pick the one whose surface owns the verb.

Anti-patterns

• Don't suggest npm, pnpm, yarn, or npx — the repo is Bun-only; bunx replaces npx.
• Don't unpin packageManager — a floating range (bun@*) defeats reproducibility.
• Don't answer test/install/runtime questions inside this router — route to the sub-skill so the answer carries the right rules.
• Don't introduce node as a runtime target — see node skill: Node 25 exists only for tools that refuse to run on Bun.

Triggers on

bun, bun 1.3.13, packageManager, which bun, bun overview