TanStack Maintain Custom Add-ons In Dev Watch
Use this skill for local add-on authoring workflows where you continuously compile and sync package output into a target app.
Setup
npx @tanstack/cli add-on init
npx @tanstack/cli add-on compile
Core Patterns
Run add-on dev loop while editing source
npx @tanstack/cli add-on dev
Sync watched framework directory into a sandbox target app
# --dev-watch is a flag on `create`, not on `dev`
npx @tanstack/cli create my-sandbox --dev-watch ../path/to/framework-dir
Re-run compile before apply when changing metadata
npx @tanstack/cli add-on compile
npx @tanstack/cli add my-custom-addon
Common Mistakes
HIGH Use --dev-watch with --no-install
Wrong:
npx @tanstack/cli create my-sandbox --dev-watch ../my-addon-package --no-install
Correct:
npx @tanstack/cli create my-sandbox --dev-watch ../my-addon-package
Dev-watch rejects --no-install, so automated loops fail before any sync work starts.
Source: packages/cli/src/dev-watch.ts:112
HIGH Start dev-watch without valid framework directory
Wrong:
npx @tanstack/cli create my-sandbox --dev-watch ../missing-or-invalid-dir
Correct:
npx @tanstack/cli create my-sandbox --dev-watch ../valid-framework-dir
Watch setup validates that the path exists, is a directory, and contains at least one of add-ons/, assets/, or framework.json. Invalid targets fail before file syncing begins.
Source: packages/cli/src/command-line.ts:599
CRITICAL Author add-on from code-router project
Wrong:
npx @tanstack/cli add-on init
Correct:
# Run add-on init from a file-router project
npx @tanstack/cli add-on init
Custom add-on authoring expects file-router mode and exits when run from incompatible project modes.
Source: packages/create/src/custom-add-ons/add-on.ts
HIGH Run add-on workflows without scaffold metadata
Wrong:
npx @tanstack/cli add-on dev
Correct:
# Run in a project scaffolded by TanStack CLI (contains .cta.json), then:
npx @tanstack/cli add-on dev
Custom add-on flows rely on persisted scaffold options, so missing metadata blocks initialization and update paths.
Source: packages/create/src/custom-add-ons/shared.ts:158
HIGH Tension: Backwards support vs deterministic automation
This domain's patterns conflict with add-addons-existing-app. Tooling assumes reusable automation, but hidden metadata preconditions from legacy support make add-on loops non-portable across repositories.
See also: add-addons-existing-app/SKILL.md § Common Mistakes