530A Model calculator MCP server

530A Model

530amodel.com — a free, privacy-first, mobile-first scenario-planning calculator for 530A custodial retirement accounts ("Trump Accounts").

No login. No email capture. No monetization. All calculation runs in your browser.

Use the public API / MCP server

The engine is free to call — no key, nothing stored, attribution to 530amodel.com asked:

GET /v1/returns; OpenAPI 3.1 with full request/response schemas)

• JSON API — https://api.530amodel.com (POST /v1/project, GET /v1/rules,

explain_530a, search, fetch; registry name com.530amodel/calculator). Works as a custom connector in Claude and ChatGPT, and with the Anthropic/OpenAI agent APIs.

• MCP server — https://mcp.530amodel.com (streamable HTTP; tools project_530a,

machine-readable maps: llms.txt, llms-full.txt

• Docs & platform quickstarts — 530amodel.com/api ·

• Contact — api@530amodel.com

Structure

packages/
  engine/     # pure TS calculation engine — zero deps, deterministic, integer-cents money
  config/     # legal figures + sources + verifiedAt + feature flags (single source of truth)
  ui/         # design tokens, shared components, charts
apps/
  web/        # Astro static site (widget, advanced model, content pages)
  workers/    # Cloudflare Workers: analytics beacon, rollup cron, newsfeed cron, email
  api/        # public calculator API (wraps the engine; OpenAPI; cache-by-input-hash)
  mcp/        # read-only MCP server (project_530a / explain_530a)
reference/    # Python reference implementation + golden-vector generator
e2e/          # Playwright specs (user journeys UC-1..UC-7)

Non-negotiables

Python reference implementation must match the TS engine to the cent).

1. Financial math is exact, deterministic, and independently tested (golden vectors from the

unverified items live behind OFF feature flags (packages/config/src/flags.ts).

1. Static-first: calculation is client-side; a million users cost the same as one.
2. Minimal dependencies, no PII, small attack surface, everything scanned in CI.
3. Every user-facing claim is honest: ranges are labeled estimates, legal figures cite sources,

Development

pnpm install
pnpm check     # lint + typecheck + test + build (same as CI)
pnpm --filter @530a/web dev

Node ≥ 22, pnpm ≥ 11. Engine numeric contract: money is integer cents (bigint), balances are quantized round-half-to-even every monthly step, display formatting only via formatMoney.

Disclaimer

This tool provides educational estimates only, not financial, tax, or legal advice. Market projections are probabilistic and not guarantees.