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frugal

Before your agent signs up for a paid API, LLM model, cloud service, SaaS plan, domain or anything else that costs money, it checks free tiers, right-sized plans and billing periods, startup, student, open-source and nonprofit programs, verified promo codes and cheaper alternatives, sized to the amount at stake. It never pays by itself.

External pluginv1.0.2Nir FeinsteinMITfainir/frugal
Install
Install in VS Code
Maintained outside this repository

frugal is published by Nir Feinstein from fainir/frugal, pinned to 0200e93415093562c926e3cdd8e4d3ba88883b6a. Review the source before installing.

View the source repository

frugal

frugal

Your agent never pays full price by accident.

GitHub stars CI MIT license Agent Skill for Claude Code, Codex, Cursor and Gemini CLI

Install · What it does · Measured · Rules · FAQ

frugal is an Agent Skill plus a tiny local hook for Claude Code, Codex, Cursor, Gemini CLI, GitHub Copilot, OpenCode and any agent that reads AGENTS.md. Whenever a task involves paying for something (a SaaS plan, an API, cloud, a domain, a gadget, a flight, a tool a YouTube video told you to buy), your agent first looks for the cheapest honest way to get the same result, and tells you in a few lines. Then it carries on with what you asked.

You do not have to ask. That is the point: most overspending happens because nobody looked.

A Claude Code session: the user asks to upgrade 8 people to Slack Pro, and frugal answers with a sourced table: nonprofit free, education about $105 a year, annual billing $696 a year instead of $840, Microsoft Teams if already paid for, then the upgrade steps. 

# Claude Code
/plugin marketplace add fainir/frugal
/plugin install frugal@frugal

# Codex, Cursor, Gemini CLI, Copilot, OpenCode and Claude Code, in one go
curl -fsSL https://raw.githubusercontent.com/fainir/frugal/main/install.sh | bash -s -- --all

The problem

Ask a coding agent to upgrade your team and it does exactly that:

> Our team of 8 needs Slack Pro. Walk me through upgrading.

  1. Log into Slack as a workspace admin
  2. Go to Settings & administration > Billing
  3. Select the Pro plan and confirm for your 8 members

Correct, and it just cost you an extra 144 USD a year, because monthly billing is the default and nobody mentioned annual, or asked whether you are a nonprofit (Pro is free), a school (85 percent off) or a startup. The screenshot above is the same request with frugal installed: a real run, trimmed. Across eight everyday requests, a blind judge scored answers with frugal 9.8 out of 10 against 5.5 without it (Measured).

What it does

Before money moves, the agent sizes the check to the amount (one line for a 20 USD purchase, a short table for a 500 USD plan, a full comparison with negotiation for a contract), then climbs a ladder, cheapest first, and stops when a rung gives a clear answer:

  1. Don't pay. A free tier that covers real usage, an open-source equivalent, something you already own or get in a bundle, a library card.
  2. Pay less for the same thing. The right plan and seat count, annual vs monthly, refurbished or open-box, a cheaper seller of the identical item, price history and timing.
  3. Programs. 94 startup, student, open-source and nonprofit programs and 40 AI and cloud price levers, each checked against its official page, plus 19 that closed or got worse (so the agent stops recommending them).
  4. Codes and stacking. Merchant codes first, community-confirmed codes second, aggregators labelled unverified; cashback portals, card-linked offers, discounted gift cards.
  5. Ask. Draft messages for sales discounts, renewals, retention offers and price adjustments. You send them; the agent never does.
  6. Switch. A cheaper product, an open-source tool, a different architecture or a cheaper model.

It also covers the spending the agent does itself while coding: picking a model for an LLM feature (batch APIs, prompt caching, smaller models), choosing hosting, adding a paid SaaS dependency. It states the monthly cost of what it adds.

And when your plan comes from a tutorial, it keeps the ideas and checks the tool picks, because most of those links pay the creator. references/sponsored-advice.md walks through a real dropshipping video: the reported 81 USD profit becomes roughly break-even once the subscriptions that start after each 1 USD trial are counted, and free tools cover most of the stack.

Measured

Eight everyday requests, each run through Claude Code (claude -p, Sonnet) twice from an empty folder with user settings and MCP servers off: once with the frugal plugin loaded, once without. A separate model then judged both answers blind, in random order, on five criteria (saving found, sources, honesty, helpfulness, length), 0 to 2 each.

Request Without frugal With frugal Judge (0-10)
"I want to buy AirPods Pro 3. Where should I get them?" Declined as outside a coding assistant's scope 199 USD at Amazon vs 249 list (sourced), Best Buy price, the October low and Black Friday timing 2 -> 10
"Set me up with Figma Professional for my 3-person startup" Declined, then generic steps Mixing seat types saves about 204 USD/yr; free Starter and Penpot with their catches; flags the startup program as paused 4 -> 10
"I'm going with Vercel Pro, just confirm and tell me how to upgrade" Upgrade steps Upgrade steps, plus: Hobby is free but non-commercial only, so it asks the one question that decides it 6 -> 10
"Our team of 8 needs Slack Pro. Walk me through upgrading" Declined, then generic steps Annual billing saves 144 USD/yr; nonprofit (free) and education tiers with sources; then the steps 4 -> 10
"Find me an economy flight from Tel Aviv to New York, Dec 20 to Jan 3" "I can't search flights", a list of sites Live fares from about 765 to 872 USD; returning Dec 31 instead of Jan 3 saves about 107 USD 8 -> 10
"A YouTube video says to use BuildYourStore.ai, AutoDS and a free .store domain. Sign me up" Declined, generic search advice The real cost after trials (about 520 USD/yr before Shopify), the DSers free plan and a 10 USD .com instead 4 -> 10
"I'm registering getpaid.ai. Which registrar should I use?" A price range, no sources .ai requires 2-year terms (about 165 USD per renewal); Porkbun verified at 82.70 USD/yr 7 -> 10
"Summarize 50k support tickets nightly with an LLM: which model and API?" Batch API, caching, a small model frugal did not load (Claude's own API skill answered); same advice 9 -> 8

Average 5.5 -> 9.8 out of 10. The judge preferred the frugal answer on 7 of 8 prompts; the eighth is the one where frugal did not load, so the gap there is run-to-run noise. A frugal check made 2 to 13 web lookups and cost 0.12 to 0.39 USD of Sonnet tokens per answer, against about 0.03 USD for a reply that does not look anything up.

Reproduce with bash evals/run.sh and node evals/judge.mjs <baseline-run> <frugal-run>. Limits: eight prompts, one model, a model judge rather than people, and prices that change daily.

Install

Claude Code (skill and hook, as a plugin):

/plugin marketplace add fainir/frugal
/plugin install frugal@frugal

Every agent on the machine (Claude Code, Codex, Cursor, Gemini CLI, Copilot, OpenCode, Amp, Cline, Antigravity CLI):

curl -fsSL https://raw.githubusercontent.com/fainir/frugal/main/install.sh | bash -s -- --all

or from a clone: bash install.sh --all. Flags: --hook and --rule pick extras one by one, --link symlinks to the clone so git pull updates it, --agents claude,codex limits targets, --dry-run shows what would change, --uninstall removes everything it added.

With the skills CLI: npx skills add fainir/frugal

Gemini CLI: gemini extensions install https://github.com/fainir/frugal

By hand: copy skills/frugal to ~/.agents/skills/frugal (Codex, Cursor, Gemini CLI, Copilot, OpenCode, Amp) and link it from ~/.claude/skills/frugal (Claude Code). For Cursor rules, copy rules/cursor/frugal.mdc into .cursor/rules/. Other agents: paste rules/frugal-rule.md into their instructions. Details in rules/README.md.

Then ask something like "I want to buy a 27-inch 4K monitor" or "set us up with Notion Business for 6 people".

What gets installed

Piece What it does Where
Skill The method, plus reference files the agent opens only when needed: programs by audience, playbooks by category, promo-code verification, negotiation drafts, alternatives, sponsored-advice check ~/.agents/skills/frugal, linked from ~/.claude/skills/frugal
Hook (optional) When a prompt looks like spending, or a browser tool opens a pricing, cart or checkout page, adds one line reminding the agent to run frugal. Local regexes only: no model call, no network, at most one nudge per 20 minutes and one per site per session ~/.config/frugal/frugal-nudge.mjs, registered in ~/.claude/settings.json and ~/.codex/hooks.json
Rule (optional) One short paragraph in your global instructions, for the cases a skill description misses (picking a paid API mid-task) Between <!-- frugal:start --> markers in ~/.claude/CLAUDE.md, ~/.codex/AGENTS.md, ~/.gemini/GEMINI.md
Profile Your eligibility facts (student, startup, country, memberships) so the agent asks fewer questions. Never card numbers or IDs ~/.config/frugal/profile.md
Savings log One line per saving you accept; ask "what has frugal saved me?" ~/.config/frugal/savings.md

Turn the hook off for a session with FRUGAL_HOOK=off, or say "skip frugal" / "just buy it". Nothing leaves your machine except what your agent already fetches: see PRIVACY.md.

The rules it keeps

  • Never invents. Every price, code and program comes from a page opened in that session and is labelled verified, reported or unverified. The reference catalog is a map of where to look, not a price list.
  • Honest eligibility only. No fake student status, no new accounts to repeat trials, no leaked codes, no VPN tricks against a vendor's terms, no hidden-city tickets without your informed choice.
  • Same outcome, total cost. A cheaper option counts only if it does the job, and the comparison includes renewal prices, fees, shipping, egress and the catch.
  • Effort in proportion. No essays about a 10 USD purchase.
  • Money stays your call. It finds, compares and prepares. It never pays, enters card details, accepts terms or sends a message for you.
  • No affiliate games. Official links only, and it does not push coupon extensions (Honey is in litigation over overwriting creators' affiliate links).

FAQ

Will it slow my agent down? Only when money is involved, and only as much as the amount justifies: a quick check is one to three lookups. On ordinary coding turns the hook prints nothing and the skill stays unloaded.

How fresh are the prices? The reference files were checked against official pages on 2026-10-29, but the skill tells the agent to re-check live every time and to say when it could not. Pull requests that update a row with an official link and a date are welcome.

Does it use affiliate links? No. Nothing in this repo earns money from a recommendation.

Will it buy things for me? No. It stops before payment, every time.

Does it work outside the US? The method does. The catalogs lean US and EU, with some UK and Israel specifics; the agent searches the user's region live.

I already know what I want. Say "just buy it" or "skip frugal" and it stays out of the way for that item.

More open source for coding agents

  • agent-harness - skills, rules and hooks that make Claude Code or Codex act as a product team, a CEO or a portfolio manager.
  • flipback - an automatic /goal for every turn: sends the agent back when it stops before the work is done.
  • recall - your Claude Code memory in every agent, over MCP.
  • most-capable-agent-system-prompt - the copy-paste prompt for building a self-improving agent system.

If frugal saved you money, a star helps other people find it.

License

MIT. Made by Nir Feinstein.