/next-partial-prefetching-adoption

name: next-partial-prefetching-adoption
description: >
  Turn on Partial Prefetching in a Next.js app and work through the
  insights it surfaces. Use when the user wants to enable or adopt
  Partial Prefetching, flip the `partialPrefetching` flag, opt routes
  in with `export const prefetch = 'partial'`, audit
  `Link prefetch={true}` behavior, preserve existing prefetched UI
  with `instant()` tests, or resolve the
  instant-link-prefetch-partial and instant-shell-url-data insights.

next-partial-prefetching-adoption

Enable Partial Prefetching and walk the app until every link reuses a shared App Shell. This skill sequences the work; per-insight recipes live in the dev overlay fix cards and their docs pages. The [Adopting Partial Prefetching guide](https://nextjs.org/docs/app/guides/adopting-partial-prefetching) is the canonical reference for the concepts this skill applies.

The development insights and the preservation tests are two different paths. Insights surface only in `next dev`, in the dev overlay's Insights tab. Test-backed preservation runs against a production-like build with `instant()` and does not need a development server. After the flag is enabled, the separate URL-data insight sweep still uses `next dev`.

preservation gate

When using test-backed preservation, the first implementation milestone is a passing flag-off `instant()` suite. Set up the production test rig, write the selected assertions, run them with `partialPrefetching` disabled, and record the command and exit status. Test-only configuration required by the rig, including [`experimental.exposeTestingApiInProductionBuild`](https://nextjs.org/docs/app/api-reference/config/next-config-js/exposeTestingApiInProductionBuild), is allowed, but until that baseline passes, do not enable `partialPrefetching` or edit the destination, cache boundaries, or Link props. Installing missing test dependencies is part of reaching the baseline, not a reason to adopt first. Use the manual path only when `rig-template.md` identifies a concrete blocker the repository cannot resolve, and record the blocker and deferred test coverage.

Talk to the user in terms of what they'll see — PRs, features, and how the app behaves after — never the insight slugs or step labels. Before you start, tell them briefly what Partial Prefetching changes: links to a route prefetch one shared App Shell, and `prefetch={true}` can also resolve cached URL-specific content. The audit determines which UI from the legacy full prefetch to preserve.

requires

• **Cache Components adopted (`cacheComponents: true`) with a passing build.** Both `partialPrefetching` and the route-level `prefetch` export require Cache Components. If it is off, use [`next-cache-components-adoption`](https://github.com/vercel/next.js/tree/canary/skills/next-cache-components-adoption) first and return after its build-blocking prerender errors are resolved. Those errors can fail `next build`; only the Partial Prefetching insights handled by this skill are non-blocking development signals.

• **Next.js 16.3 or later.** `partialPrefetching`, the `prefetch` route segment config, and the prefetch insights all land there.

• **A browser you can drive.** Test-backed preservation uses an existing or minimal production-mode Playwright suite; manual preservation and the final demonstration use the running production app. The development insight path and the post-flag URL-data sweep use [`next-dev-loop`](https://github.com/vercel/next.js/tree/canary/skills/next-dev-loop); install it before either development pass unless it is already available (`npx skills add https://github.com/vercel/next.js/tree/canary/skills/next-dev-loop`). If the app is webpack-pinned, drive a browser directly (`agent-browser`, Playwright) — you lose the framework cross-checks, not the insights; they're still in the overlay and the dev log.

• **A runnable app.** Preservation and the final demonstration need a production-like build because automatic prefetching runs only in production. The development server is required only when using the insight path or running the post-flag URL-data sweep; do not start it merely to confirm a test-backed preservation case. If the app reads a database or required environment at import, confirm the environment used by the chosen path can start before step 1.

notes

• **Offline docs.** Guide links have offline copies under `node_modules/next/dist/docs/` (bundled since Next.js 16.2), with the directory layout numbered for ordering (e.g. `node_modules/next/dist/docs/01-app/02-guides/adopting-partial-prefetching.md`). If you can't predict the numbered prefix, `find node_modules/next/dist/docs -name '<slug>.md'` resolves it. The `/docs/messages/*` error pages are not bundled.

• **Older versions without bundled docs.** Suggest `npx @next/codemod@latest agents-md` to the user before starting: it downloads a version-matched copy to `.next-docs/` and writes an index into `AGENTS.md`. It touches files in their repo, so ask first and run it only if they want it.

background

Adopting Partial Prefetching means every route preserves the prefetched UI that matters, now split between the shared App Shell and any extra per-link data a link explicitly asks for. The [guide](https://nextjs.org/docs/app/guides/adopting-partial-prefetching) is the canonical reference for what a prefetch contains and how to decide each case; this skill sequences that work against a running app.

The catch that decides most of the sweep: a default link warms only the shared App Shell. A route keyed by `params` or `searchParams` can prefetch more only after it has adopted Partial Prefetching and a specific link uses [`<Link prefetch={true}>`](https://nextjs.org/docs/app/api-reference/components/link#prefetch); then Next.js resolves the URL data and any cached content behind it before the click (the guide's [URL data](https://nextjs.org/docs/app/guides/adopting-partial-prefetching#url-data) section).