Vercel Speed Audit

Optimize Vercel build and deploy speed — audit checklist for new and existing projects.

Security Scan

The skill's files and runtime instructions match its stated purpose (audit and optimize Vercel build/deploy speed); it is an instruction-only checklist and does not request unrelated credentials or install code.

Purpose & Capability

Name/description (Vercel speed audit) align with contents: checklist, framework-specific guides, CI/workflow examples and CLI snippets. All requested actions (vercel CLI, depcheck, editing vercel.json, GitHub Actions workflows, SvelteKit adapter changes) are coherent with optimizing Vercel builds.

Instruction Scope

SKILL.md and docs contain concrete commands and file edits scoped to a project's repo and Vercel settings (e.g., git diff-based ignoreCommand, `vercel build`, `vercel deploy --prebuilt`, `vercel pull`, reading project config files). There are no instructions to read unrelated system files or to exfiltrate data to unexpected endpoints. Some steps (e.g., vercel pull, vercel deploy, vercel rollback) will access or modify remote project state when run — this is expected for the documented tasks and is clearly indicated.

Install Mechanism

No install spec or bundled code; instruction-only skill. No downloads or archive extraction. Low install risk — everything is documentation and CLI guidance.

Credentials

The skill declares no required env vars. The docs reasonably describe typical CI secrets (VERCEL_TOKEN, VERCEL_ORG_ID, VERCEL_PROJECT_ID) needed for automated workflows; those are proportional to the documented GitHub Actions + prebuilt pattern. There are no unrelated or unexpected credential requests in the skill.

Persistence & Privilege

always: false and no install steps that persist or modify other skills or system-wide agent config. The skill does include instructions that, when executed by a user or CI, will perform deploys/rollbacks — but that is consistent with its purpose and requires explicit credentials to act on remote projects.

Assessment

This is a documentation-only audit tool and appears coherent with its purpose. Before using: - Be careful with commands that change remote state: `vercel deploy`, `vercel deploy --prebuilt`, and `vercel rollback` will modify deployments when run with valid tokens. - Store any Vercel tokens (VERCEL_TOKEN) as least-privileged CI secrets and only add them to trusted workflows; do not paste tokens into chat or public places. - Review any CI workflow YAMLs before applying them to your repository (concurrency, artifact sizes, and `vercel pull` behavior are documented here). The provided GitHub Actions examples assume you have deploy permissions for the project/org. - The skill’s suggested scripts that read git diffs or write `.vercel` files operate on your repo; audit those scripts before enabling them in production to avoid unintentional skips or exposure of environment files. - Because this is instruction-only (no code installed by the skill), nothing will run automatically on your machine just by installing the skill — however, if you give a process a Vercel token or run the provided commands in CI, they can deploy/rollback. Ensure credentials and permissions are controlled accordingly.

Vercel Speed Audit Skill

Optimize Vercel build and deploy speed for any project. Run as a checklist when starting new projects or auditing existing ones.

When to Use

• New project setup — configure optimal defaults from day one
• Build times creeping up — audit and fix performance regressions
• Deploy queue bottlenecks — eliminate waiting on concurrent builds
• Production incidents — use instant rollback instead of waiting for a new build
• Cost optimization — balance speed vs spend on build infrastructure

Triage First (Don't Blindly Run All 10)

Before running the full checklist, measure and assess:

# 1. Check current build times
cd <project> && npx vercel ls --limit 5

# 2. Check team/plan tier
npx vercel team ls

Decision tree:

Build Time	Action
< 20s	Only do items 0, 1, 3-5, 10. Skip GitHub Actions (#8), skip barrel file audit (#6) unless codebase is large.
20-60s	Do items 0-7, 10. GitHub Actions (#8) is optional.
60s+	Do everything. GitHub Actions (#8) becomes high-value.

Auth-gated app? (All pages behind login) → Skip ISR (#9) entirely. ISR caches one response for all users — incompatible with per-user content.

Framework: → SvelteKit: Also read docs/sveltekit.md — includes adapter-vercel switch, prerendering, $env tips. → Next.js/Nuxt/Other: docs/general.md covers framework-agnostic items.

Checklist (Ordered by Impact)

#	Optimization	Impact	CLI-checkable?	Plan Required
0	Use explicit adapter (e.g., adapter-vercel not adapter-auto)	Faster, no detection overhead	✅ Check config	Any
1	Turbo Build Machines	50-70% faster builds	❌ Dashboard only	Pro+
2	On-Demand Concurrent Builds	Eliminates deploy queue	❌ Dashboard only	Pro+
3	Prerender Static Pages	Fewer functions, faster TTFB	✅ Audit code	Any
4	Ignored Build Step	Skip irrelevant builds	✅ Check vercel.json	Any
5	Prioritize Production Builds	Prod deploys go first	❌ Dashboard only	Pro+
6	Eliminate Barrel Files	10-30% build speedup	✅ Audit code	Any
7	Audit & Trim Dependencies	Faster install + bundle	✅ Run depcheck	Any
8	GitHub Actions + --prebuilt	Full cache control, skip Vercel build	✅ Add workflow	Any
9	ISR for Dynamic Pages	Fewer cold starts	✅ Audit routes	Any
10	Instant Rollback	Zero-downtime recovery	✅ vercel rollback	Hobby: last only; Pro+: any

Pro plan items (#1, #2, #5): If not on Pro, check team plan first. These are the highest-impact free wins on Pro.

Dashboard Links (Can't Check via CLI)

For a team called <team-slug>:

• Turbo machines: https://vercel.com/<team-slug>/<project>/settings → General → Build Machine
• Concurrent builds: https://vercel.com/teams/<team-slug>/settings → Build Queue
• Prioritize prod: https://vercel.com/<team-slug>/<project>/settings → Git → Production prioritization

Docs

• docs/checklist.md — Full detailed checklist with how-to for each item
• docs/sveltekit.md — SvelteKit-specific optimizations
• docs/general.md — Framework-agnostic Vercel optimizations
• docs/github-actions-prebuilt.md — GitHub Actions + vercel deploy --prebuilt guide

Lessons Learned

Real-world findings from running all 10 checks on a SvelteKit project with 16-18s builds:

1. Half the checklist was overkill — builds were already fast. Triage step now prevents wasted effort.
2. ISR is irrelevant for auth-gated apps — every page served per-user content. Added decision tree.
3. adapter-auto → adapter-vercel was a missed win — not in original 10 but came up in dep audit. Now item #0.
4. Dashboard-only settings are the highest-impact items (Turbo, concurrent, priority) but can't be verified via CLI. Added direct links.
5. GitHub Actions + prebuilt only worth it at 60s+ — for fast builds, the Vercel Git integration is simpler and equally fast.
6. The dep audit found the project was already lean (11 deps, 84MB node_modules, 472K client bundle). Only one unused dep (clsx).
7. Team/plan tier gates most high-impact items — checking plan should be step 1.

Quick Start

1. Triage: Measure build times + check plan tier
2. Run applicable items from the checklist based on decision tree
3. If SvelteKit, also review docs/sveltekit.md
4. Track findings in a report file (e.g., vercel-speed-report.md)
5. For complex CI needs, follow docs/github-actions-prebuilt.md