vercel-optimize

The saved excerpt is a snapshot from when this skill was listed. The external source remains the complete and most current version.

---
name: vercel-optimize
description: "Use for Vercel cost and performance optimization on deployed projects, especially Next.js, SvelteKit, Nuxt, and limited Astro apps. Collect Vercel metrics, usage, project config, and code scan results first; investigate only metric-backed candidates; produce ranked recommendations grounded in verified files and version-aware Vercel/framework docs. Trigger for Vercel bill reduction, slow or expensive routes, caching opportunities, Function Invocations, Build Minutes, Fast Data Transfer, Core Web Vitals, Bot Management, Fluid compute, or cost breakdown requests."
metadata:
  version: "1.2.0"
---

# Vercel Optimize

Run an observability-first Vercel optimization audit. Do not inspect source files until `signals.json` exists and a deterministic gate points to a route, file, or project setting.

Core doctrine: read [references/doctrine.md](references/doctrine.md) if any rule is unclear.

- Metrics first. Recommendations start from Vercel production signals, not repo-wide grep.
- Deterministic gates. `scripts/gate-investigations.mjs` decides what deserves investigation.
- Candidate-bound scope. Read only files named by a candidate or a route-local import chain.
- Version-aware citations. Use only `references/docs-library.json`; invalid or version-mismatched citations are stripped.
- Customer copy. Read [references/voice.md](references/voice.md) before writing report text or chat output.

## Prerequisites

- Vercel CLI v53+ with `vercel metrics`, `vercel usage`, `vercel contract`, and `vercel api`.
- Authenticated CLI session: `vercel login`.
- Linked app directory: `vercel link`. `VERCEL_PROJECT_ID` can help resolve project config, but `vercel metrics` still requires directory linkage. The link or environment must include the intended project org/team/user scope so the collector can resolve a CLI-safe `--scope` and keep `vercel metrics`, `vercel usage`, and `vercel contract` on the same account.
- Node.js 20+.
- Observability Plus for route-level metric-backed recommendations.

Never put auth tokens in shell commands. Do not type `VERCEL_TOKEN=...`, `--token ...`, or `Authorization: Bearer ...` into commands that may be echoed in chat.

## Framework Support

The preflight reads `package.json` and sets expectations before metric fan-out.

| Framework | Status | Notes |
|---|---|---|
| Next.js App Router | supported | strongest route mapping, scanners, playbooks, citations |
| Next.js Pages Router | supported | scoped to Pages Router idioms when detected |
| SvelteKit | supported | route mapping for `src/routes` files and SvelteKit scanner |
| Nuxt | supported | route mapping plus generic/platform checks; fewer framework-specific recs |
| Astro | limited | route mapping plus generic checks; fewer framework-specific recs |
| Hono / Remix / unknown | blocked by default | continue only if the user accepts a limited platform/code-only audit |

If unsupported, stop and ask before scanning or gating:

```text
This project uses <framework>. Vercel Optimize supports metric-backed code recommendations for Next.js, SvelteKit, and Nuxt. Astro support is limited. For <framework>, I can still run a limited platform/scanner audit, but route-level Vercel metrics may not map back to source files.

Do you want me to continue with the limited audit, or stop here?
```

If the user continues, rerun collection with `--continue-unsupported-framework`.

## Run Directory

Use a fresh run directory for every audit. Do not reuse briefs, sub-agent outputs, or reports across runs.

```bash
RUN_DIR="$(mktemp -d -t vercel-optimize-XXXXXX)"
```

## Pipeline

### 1. Collect, scan, and merge signals

Run from the linked app directory or pass `--cwd` where a script supports it. Keep stdout JSON separate from stderr logs. Do not combine streams.

```bash
node scripts/collect-signals.mjs [projectId] > "$RUN_DIR/vercel-signals.json" 2> "$RUN_DIR/collect.stderr"
node -e 'JSON.parse(require("fs").readFileSync(process.argv[1], "utf8")