policyengine-user-guide

A guide to using PolicyEngine, a free website that calculates taxes and government benefits for households or whole populations. It covers the household calculator, policy editor, and population-wide results for the United States, United Kingdom, and Canada.

In plain words
What is it for?
Use it to enter household details, compare the effects of policy changes, design custom reforms, view wider population impacts, and share a reform by link.
Why use it?
It explains how to model a household’s situation or test a proposed tax or benefit change without needing to know how the website is built.

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

Made for: Claude Code, Codex.

Per session 103 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,370 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. 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 $0.00103 $0.01370
Opus 5 $0.00051 $0.00685
Sonnet 5 $0.00021 $0.00274
Haiku 4.5 $0.00010 $0.00137

Measured 2d ago against content hash a81c4738524a, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

policyengine-user-guide scanned grade A with 0 findings 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.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/policyengine-user-guide/SKILL.md · 110 lines

How it starts

The opening of the file, as written. The whole thing — 110 lines — stays where its author put it; the contents beside it link to each section on GitHub.

PolicyEngine user guide

Help someone use policyengine.org to compute how a policy affects a specific household or the population. The app has three stable surfaces: a household calculator, a policy editor, and society-wide impact results. Exact labels and layout evolve — describe the flow by these concepts rather than memorized button text.

What PolicyEngine does

PolicyEngine computes the impact of tax and benefit policy on households and society. Users can calculate their own taxes and benefits, design a custom reform, see population-wide impacts, and share a reform by link. It is a nonpartisan nonprofit; the site is free.

Countries: United States (policyengine.org/us), United Kingdom (/uk), and Canada (/ca).

Household calculator

The household flow answers "how does this policy affect this household?"

  1. Describe the household. Enter the people (ages, marital status, dependents), their income by type (employment, self-employment, capital gains, pensions, benefits received), the location (US state or UK region, plus any local options the model supports), and any deductions/expenses the model uses (e.g. charitable giving, mortgage interest, SALT, medical).
  2. Read the results. Net income after taxes and benefits, broken into total tax, total benefits, and effective and marginal tax rates, with charts of net income and marginal rate across an earnings range.
  3. Apply a reform. Layer a policy reform on top to compare baseline vs. reform for the same household.

Policy editor

The policy flow answers "what does this reform do to the population?"

  1. Pick parameters to change. Browse the parameter tree by government department and program (e.g. IRS credits, SNAP, Universal Credit), select a parameter, and set a new value or schedule. Verify the parameter's current baseline before changing it — post-OBBBA US law differs from older summaries (e.g. the CTC baseline is $2,200 in 2026, not $2,000).
  2. Run the society-wide impact. The app computes the reform against microdata and returns:
    • Budgetary impact — total cost or revenue, broken down by program.
    • Poverty impact — change in poverty rate, by age group and for deep poverty.
    • Distributional impact — average change and winners/losers by income decile.
    • Inequality impact — Gini index and top-income shares.

Read the full file on GitHub · 110 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 · 110 lines · 103 tokens per session scan A a81c4738524a

Subscribe to this mod's changes

policyengine-user-guide is a skill published in the GitHub repository PolicyEngine/policyengine-claude (31 stars, last pushed 7d ago), licensed MIT. It adds 103 tokens to every session and 1,370 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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