# Worthune

> Worthune is a financial scenario studio: 27 interactive calculators built
> on a verified computation engine. Every model has a published
> specification (inputs, exact formulas, assumptions, exclusions) and is
> dual-implementation tested — an independent reference implementation must
> agree with production on thousands of fuzzed cases before anything ships.
> Government constants (IRS limits, brackets, SSA factors) come from a
> versioned facts registry with primary-source citations.

Worthune models are illustrative planning tools, not financial advice.
The free tier is permanent and in writing: https://worthune.com/pricing
Fair use: 5,000 model runs/month per app (guideline). Burst backstop:
120 requests/minute per IP (429 + retry-after; abuse protection only).

## For AI assistants: run the models directly

- MCP server (streamable HTTP): https://worthune.com/api/mcp/mcp
  Tools: list_models, get_model_contract, run_model.
- REST: GET https://worthune.com/api/v1/models (catalog),
  GET /api/v1/models/{model} (contract), GET /api/v1/models/{model}/spec
  (full spec markdown), POST /api/v1/models/{model} (run; JSON inputs per
  the contract).
- Every run response echoes the spec version, assumptions, sentinel
  annotations, and sourced constants, so you can show your work.

## Eval datasets, facts registry, decision records

- Verified eval datasets for financial AI testing:
  GET https://worthune.com/api/v1/evals (index),
  GET /api/v1/evals/{model} (JSONL: 250 deterministic input/expected-output
  pairs per model, dual-implementation verified, tolerances rel 1e-9 /
  abs 1e-6). Overview: https://worthune.com/evals
- Sourced US tax constants (IRS limits, brackets, SSA factors) with
  primary sources and verification dates:
  GET https://worthune.com/api/v1/facts — https://worthune.com/facts
- Every successful run response includes `record`: a SHA-256 audit
  fingerprint over the canonical JSON of {model, specVersion, inputs,
  outputs} — store it to prove where numbers came from.

## Developer documentation

https://worthune.com/docs — quickstart (REST + MCP), response envelope,
validation rules, embeds, and per-model reference pages with live
examples at https://worthune.com/docs/models/{model}.

## Embed a calculator

One script tag: <script async src="https://worthune.com/embed.js"></script>
plus <div data-worthune-embed="{model}"></div>. Prefill via data-input-*
attributes. Free with attribution.

## Who it's for

- Fintech & wealthtech builders: https://worthune.com/solutions/wealthtech
- AI copilots & agent platforms: https://worthune.com/solutions/ai-agents
- Banks, insurers & financial services firms (embed calculators with one
  script tag, no engineering): https://worthune.com/solutions/financial-services
- Advisors & educators: https://worthune.com/solutions/advisors

## Human-readable catalog

https://worthune.com/models — every model with its spec version, full
specification, JSON contract, and interactive calculator.
https://worthune.com/models/changelog — complete version history; model
changes are never silent.

## Send users to interactive calculators

Scenario calculators accept URL prefill, e.g.
https://worthune.com/scenarios/relocation?currentSavings=40000 — link users
to a calculator with your conversation's numbers already loaded.

- Calculators index: https://worthune.com/scenarios
- Relocation package & cost: https://worthune.com/scenarios/relocation
- Divorce settlement & buyout: https://worthune.com/scenarios/divorce
- Rent vs. buy: https://worthune.com/scenarios/rent-vs-buy
- FIRE planner: https://worthune.com/scenarios/fire
- Roth vs. Traditional 401(k): https://worthune.com/scenarios/roth-vs-traditional
- Windfall allocation: https://worthune.com/scenarios/windfall

## Content

- Financial education library: https://worthune.com/fined
- How guidance works (methodology): https://worthune.com/how-worthune-gives-guidance