Manifestack is a skill for your coding agent (Claude Code, Cursor, Codex and others). Ask it to check your stack, and it finds the bills, outages and compliance gaps ahead of you, with a fix for each and every price read from the vendor's own page.

Quick start

npx manifestack

Then ask your agent to check your stack, or run /manifestack.

What it does

• New project: asks about users, budget, data rules and your team, then picks hosting, database, auth, email and the rest, priced at 1k, 10k and 100k users, and says what you don't need.
• Existing project: scans the whole product (JS, Python and Go dependencies, config files, env var names) and reports what breaks or costs too much, by severity, with a fix for each.
• Every change: in Claude Code and Cursor, a hook flags each new vendor SDK and checks it against your requirements before you rely on it.

It never changes your code or vendor settings, needs no API keys or account, and writes only .manifestack/STACK.md.

Usage

Command	What it does
/manifestack	init on an empty repo, audit otherwise
/manifestack init "B2B dashboard, EU users"	Proposes and prices a whole stack
/manifestack audit	Checks every service against your requirements, budget and growth

You can also just ask: "what breaks first at 50k users?" or "what should we build this on?".

Example: an audit of a demo product (Next.js, FastAPI and Go, 7 vendors)

_{A real run: usage numbers are the demo's, every price and limit was read from the vendor's page on Oct 8, 2026.}

Severity	Finding	When	Cost	Fix
Critical	Risk Vercel's default $200 on-demand budget runs out mid-month at ~$340/mo of overage, and production deployments pause by default	Every month, ~18th	Site down until each project is resumed by hand	Turn on Flat Rate CDN (below), which ends the overage; until then raise the budget in Settings → Billing → Spend Management
Critical	Requirement Supabase project in us-east-1, STACK.md requires an EU database	Now	~1 day of migration	New project in eu-central-1, move the 312 MB now; pin Vercel functions to fra1
Critical	Risk Resend allows 10 API requests/s; the weekly digest sends 9,000 emails, 50 in parallel	Mondays	Digests lost to 429 errors	Throttle the worker to 10 requests/s, retry 429 with backoff
Critical	Requirement OpenAI's trust page does not confirm the API is in its SOC 2 Type 2 scope (unverified)	Before the next security review	—	Check OpenAI's product compliance status page for the API
High	Bill At 50k users (the Q3 plan in STACK.md) the stack costs ~$4,580/mo; Vercel transfer is $2,684 of it	By Q3	~$55k/yr against a ~$600/mo budget	With Vercel Flat Rate CDN the same 50k users cost ~$1,920/mo, and today ~$350/mo instead of ~$690/mo
High	Bill Vercel Pro: 3.4 TB of Fast Data Transfer billed on demand ($0.15/GB past 1 TB), +0.3 TB/mo	Now, growing	~$360/mo, ~$2,684/mo at 50k users	Billing → Flat Rate CDN: the $20/mo tier covers 50 TB and 10M CDN requests (check Usage → CDN Requests first)
High	Risk OpenAI Build tier caps usage at $500/mo; spend is $310, +21%/mo	~Dec 2026	API calls blocked until the month resets	Top up to $100 in total credit purchases to reach Launch ($5,000/mo cap)
Medium	Limit Resend Pro: 41,200 / 50,000 emails, +18%/mo	~Nov 2026	+$15/mo on the 100k tier	Move to the 100k tier ($35/mo) before November
Medium	Limit Supabase Free: 312 / 500 MB, read-only above it, +1.1 MB/day	~Mar 2027	$25/mo on Pro	Archive events rows older than 90 days, or upgrade with the EU move
Low	Overlap Clerk and Supabase Auth both sign users in	Now	Two user stores	Move team invites to Clerk, remove Supabase Auth

Example: init for a new EU B2B dashboard

B2B dashboard for EU customers, ~1k users at launch, 2 React devs, $150/mo max, cheaper is better. Was going to put Next.js on EKS. Sane?

Skip Kubernetes. The EKS control plane alone is ~$73/mo, half your budget, before any server, load balancer or database, and you would run it. A whole stack in the EU for ~$71/mo, built for lowest cost:

Layer	Pick	At launch	Why
Frontend	React SPA (Vite), static files on Cloudflare	$0	No SSR needed behind a login, and you already know React
Backend	Supabase Pro in Frankfurt: Postgres, auth, API	$25/mo	The Postgres you know, with auth and the API in one EU project
Email	Resend Pro, sending domain in Ireland	$20/mo	The free plan caps 100 emails a day, too tight for a launch
Errors	Sentry Team, EU organization in Frankfurt	$26/mo	Two developers; the free plan is for one user only

Users	1k	10k	50k	100k
Per month	$71	$71	$131	$266

Fits the $150/mo budget up to ~55k users; email is what grows. Less to run instead: Next.js on Vercel Pro with the same backend, ~$111/mo. Not needed: Kubernetes, SSR, a separate auth service. Decide now: create Supabase in eu-central-1 and Sentry in the EU; neither region can be changed later.

Install

npx manifestack detects your agent. To pick one:

Agent	Install	Run
Claude Code	npx manifestack --agent claude-code	/manifestack
Cursor	npx manifestack --agent cursor	ask the agent to run manifestack
Codex	npx manifestack --agent codex	$manifestack

It also detects Copilot, Windsurf, OpenCode, Cline and Gemini CLI. npx manifestack uninstall removes everything except .manifestack/.

Other ways to install

Claude Code plugin (run it as /manifestack:manifestack):

/plugin marketplace add manifestack/manifestack
/plugin install manifestack@manifestack

skills CLI (skills only; /manifestack offers to add the hook later):

npx skills add manifestack/manifestack

Manual:

git clone https://github.com/manifestack/manifestack
mkdir -p .agents/skills                                # Claude Code: .claude/skills/
cp -r manifestack/skills/manifestack manifestack/skills/manifestack-guard .agents/skills/

STACK.md

Your requirements and decisions, in .manifestack/STACK.md. Commit it; every audit and new service is checked against it.

## Requirements
budget: ~$600/mo
users: 9k now, 50k by Q3
requires: EU database, SOC 2 vendors
avoid: Kubernetes
priority: least ops

## Database: Supabase
plan: free
limit: 500 MB database, pauses after 7 days idle
source: supabase.com/pricing  # read 2026-10-06
revisit_when: db_size > 400 MB OR date >= 2027-02-01

Decisions are written only after your yes; secrets never go in. Full format.

Vendors

Works with any vendor. Built-in page maps make these faster and more reliable:

Role	Vendors
Hosting	Vercel, Netlify, Cloudflare, Railway, Render, Fly.io, Heroku, DigitalOcean
Database	Supabase, Neon, Firebase, PlanetScale, MongoDB Atlas, Upstash, Convex
Auth	Clerk, Auth0, WorkOS
Email	Resend, Postmark, SendGrid
Storage	Cloudinary, UploadThing
Payments	Stripe, Paddle, Lemon Squeezy, Polar
Mobile	RevenueCat, Adapty, Expo EAS
Monitoring	Sentry, PostHog, Datadog
AI	OpenAI, Anthropic, Google Gemini

Request a map.

Contributing

See CONTRIBUTING.md. Security issues: SECURITY.md.

License

MIT