policyengine-tools

A skill guide for building standalone PolicyEngine calculators, dashboards, and interactive data tools. It describes a Next.js and TypeScript setup, shared UI components, Tailwind CSS styling, Vercel deployment, and embedding into policyengine.org.

In plain words
What is it for?
Use it to create or deploy PolicyEngine interactive tools, configure their shared UI and styling, and connect them to the main site's multizone routing.
Why use it?
It helps prevent integration mistakes when a separate web tool must work both on its own and inside the main PolicyEngine website.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/policyengine/policyengine-claude/policyengine-tools
Any agent
npx skills add PolicyEngine/policyengine-claude --skill policyengine-tools
Clone the repo
git clone --depth 1 https://github.com/PolicyEngine/policyengine-claude

Made for: Claude Code, Codex.

Per session 179 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,839 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00179 $0.03839
Opus 5 $0.00089 $0.01920
Sonnet 5 $0.00036 $0.00768
Haiku 4.5 $0.00018 $0.00384

Measured 2d ago against content hash 069a757b4937, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

policyengine-tools scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

Vercel. Modal apps can silently disappear — if the frontend gets network errors, `curl` the
skills/policyengine-tools/SKILL.md · 266 lines

How it starts

The opening of the file, as written. The whole thing — 266 lines — stays where its author put it; the contents beside it link to each section on GitHub.

PolicyEngine standalone tools

How to build calculators, dashboards, and visualizations that deploy independently to Vercel and slot into policyengine.org as Next.js multizones. New tools are their own repos; the host (policyengine-app-v2/website/) proxies a URL path to each tool's Vercel deployment.

Required stack

  • Next.js (App Router) — not Pages Router, not Vite as the app bundler (Vite only backs Vitest). next.config.ts + app/ with layout.tsx + page.tsx, TypeScript.
  • Tailwind v4, CSS-first — no tailwind.config.{ts,js}. globals.css is exactly:
    @import "tailwindcss";
    @import "@policyengine/ui-kit/theme.css";   /* both required; Tailwind must come first */
    
  • PostCSS is required for Next — create postcss.config.mjs with { plugins: { "@tailwindcss/postcss": {} } } and install @tailwindcss/postcss + postcss as devDeps. (A Vite tool uses the @tailwindcss/vite plugin instead and needs no PostCSS config.) The theme.css header itself states @tailwindcss/postcss is mandatory — the older "no postcss.config" guidance was wrong.
  • @policyengine/ui-kit (bun add @policyengine/ui-kit) — use its components before building your own. See policyengine-design for the full 0.4.0 export list.
  • bun for everything (bun install, bun run build, bunx; bun.lock committed).
  • Vercel deploy under the policy-engine scope. Static-only tools may use output: 'export'; tools with a Modal backend stay server-rendered.

Scaffold: bunx create-next-app@latest my-tool --ts --app --tailwind --eslint --import-alias "@/*", then bun add @policyengine/ui-kit and set up globals.css as above.

ui-kit components (verified 0.4.0)

Prefer these over hand-rolled equivalents; import from @policyengine/ui-kit:

Need Component
Page shell / layout DashboardShell, SidebarLayout, SingleColumnLayout, InputPanel, ResultsPanel, Stack, Group, Container
Header + footer Header, Footer (Header props: navItems, logoSrc, linkComponent, countriesnot variant/navLinks)
Inputs CurrencyInput, NumberInput, SelectInput, CheckboxInput, SliderInput, InputGroup
Primitives Button, Card, Badge, Tabs, Dialog, Select, Tooltip, Alert, Switch, SegmentedControl, …
Display MetricCard, SummaryText, DataTable, PolicyEngineWatermark
Charts ChartContainer, PEBarChart, PELineChart, PEAreaChart, PEWaterfallChart
Maps USDistrictChoroplethMap, UKConstituencyChoroplethMap, HexagonalMap, HouseholdGraph
Utils formatCurrency, formatPercent, formatNumber, cn, logos

Read the full file on GitHub · 266 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 266 lines · 179 tokens per session scan A 069a757b4937

Subscribe to this mod's changes

policyengine-tools is a skill published in the GitHub repository PolicyEngine/policyengine-claude (31 stars, last pushed 7d ago), licensed MIT. It adds 179 tokens to every session and 3,839 once invoked, about $0.0009 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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