Add Add-ons To Existing App

Use this skill when the project already exists and you need to layer add-ons safely without breaking dependency or metadata assumptions.

Setup

npx @tanstack/cli add clerk drizzle

Core Patterns

Add multiple integrations in one pass

npx @tanstack/cli add tanstack-query drizzle

Resolve candidate ids before applying

npx @tanstack/cli create --list-add-ons --json

Validate optionized add-ons before install

npx @tanstack/cli create --addon-details prisma --json

Common Mistakes

CRITICAL Run tanstack add without .cta.json

Wrong:

npx @tanstack/cli add clerk

Correct:

# Run in a project scaffolded by TanStack CLI (contains .cta.json), then:
npx @tanstack/cli add clerk

Add flows depend on persisted scaffold metadata, so commands can fail or apply incomplete config when .cta.json is missing.

Source: packages/create/src/custom-add-ons/shared.ts:158

HIGH Use invalid add-on id

Wrong:

npx @tanstack/cli add drizle

Correct:

npx @tanstack/cli add drizzle

Unknown ids stop resolution and force manual correction before any add-on work proceeds.

Source: packages/create/src/add-ons.ts:44

HIGH Ignore add-on dependency requirements

Wrong:

npx @tanstack/cli add custom-addon-with-missing-deps

Correct:

npx @tanstack/cli add required-dependency custom-addon-with-missing-deps

Add-ons with dependsOn can fail during finalization if required dependencies are not present.

Source: packages/create/src/add-ons.ts:48

MEDIUM Assume old Windows path bug still present

Wrong:

# Avoid tanstack add on Windows and patch manually

Correct:

npx @tanstack/cli add clerk

Avoiding supported workflows based on historical bug reports causes unnecessary manual drift. Fixed in newer versions, but agents trained on older threads may still avoid this path.