vercel / flags

That one skill, flags-sdk, covers installing the flags npm package, declaring flags with flag(), wiring the vercelAdapter through OIDC or SDK keys, and swapping in adapters for Statsig, LaunchDarkly, PostHog, GrowthBook, Global Config, OpenFeature, Split, Flagsmith, Reflag, Optimizely, or a custom provider instead. It also covers the full vercel flags CLI — create, inspect, enable, disable, split, rollout, targeting rules, segments, evaluations, versions, archive, sdk-keys, and override — plus precompute, identify/dedupe, and the Flags Explorer and Toolbar, for both Next.js and SvelteKit.

This is for a team already on Next.js or SvelteKit that wants feature flags or an A/B test wired into a Server Component, a Pages Router route, or Routing Middleware, from the team that also builds Next.js itself. The README is explicit that the SDK works with any flag provider, a custom setup, or no provider at all — but that flexibility is about where a flag's value comes from, not about whether any setup is required at all.

READ THE FULL ANALYSIS＋

"No flag provider at all" is not the same as "no setup." A FLAGS_SECRET environment variable — 32 random bytes, generated once per environment and marked sensitive in Preview and Production — is required before the SDK will run under any configuration; it's what decrypts overrides and encrypts any flag value sent to the client. Choosing a hosted provider such as LaunchDarkly or Statsig adds that provider's own key on top of it.

Checked 19 September 2026 from the skill's own trigger description and the package README; we have not tested the named provider adapters ourselves, only confirmed each is named in the skill's own trigger list.