Manifestack

Know what your stack will cost before the bill arrives.

Manifestack is a free skill for your coding agent (Claude Code, Cursor, Codex and others). Ask what your stack will cost at 50k users: it prices every service at your usage on the vendor's own pages and finds the bills ahead of you, each with the fix that cuts it. The same report flags the plan limits that take a product down, data rules it breaks and services you pay for twice.

For developers, small teams and agencies who build with a coding agent and pick their own services, from Vercel and Supabase to AWS. Not a FinOps tool for large cloud accounts.

Audit of a demo product (Next.js, FastAPI and Go, 7 vendors). Usage numbers are the demo's; every price and limit was read from the vendor's page on Oct 8, 2026.

Quick start

Requires Node.js 22 or newer.

npx manifestack

Then run /manifestack, or just ask your agent: "what will we pay at 50k users?", "what breaks first?", "what should we build this on?", "Neon or Supabase for this app?".

What it does

• Prices your stack as it grows. Every service at your usage, now and at 10k, 50k or 100k users, read from the vendor's current pricing page. Each bill comes with what cuts it: a plan or tier that fits, a setting, a service you don't need.
• Finds what breaks before then. Free-tier caps, rate limits, spend limits that pause production, with the date each one hits.
• Checks the rest of the fit. Data rules (EU region, SOC 2), two services doing one job, and setups built for far more users than you have.
• Remembers why. Budget, requirements and decisions live in .manifestack/STACK.md, so the next audit, the next teammate and the next agent session start from them.

Every price cites the page and the date it was read. A page it can't open is marked unverified, never filled from memory.

At every stage

• New project: asks about users, budget, data rules and your team, then picks hosting, database, auth, email and the rest, priced from launch to 100k users, and says what you don't need.
• Existing project: scans the whole product (JS, Python and Go dependencies, Terraform, Bicep and CloudFormation, CI deploy steps, config files, env var names) and reports what costs too much, hits a limit or breaks a rule, by severity, with a fix for each.
• Choosing a vendor: compares two or three vendors for the same job on your workload: cost at your size, requirements, the first limit, the features you use and what it takes to leave.
• Every change: in Claude Code and Cursor, a hook flags each new vendor SDK and checks it against your budget and requirements before you rely on it.

It never changes your code or vendor settings and needs no API keys or account. The skill writes only inside .manifestack/: STACK.md, plus working files in .manifestack/tmp/ that git ignores. The installer adds the skill folders and, for Claude Code and Cursor, one hook entry; npx manifestack uninstall removes them.

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	Prices every service at your usage and growth, and lists what to fix
/manifestack compare neon supabase	Puts two or three vendors side by side, priced on your workload

Example: the full audit from the image above