For developers & AI assistants
Financial models that show their work
Every model here tells you what it takes in, what it computes, what it assumes, and what it leaves out — before you run it. A second, independent implementation has to reproduce the engine exactly before anything ships, every IRS and SSA constant is traced to its source, and when a model changes, the changelog tells you.
Watch the film — Two Implementations or It Doesn’t Ship, 3½ minutes
Use the models
MCP server (AI assistants): https://worthune.com/api/mcp/mcp — your agent lists the catalog, reads the contract, runs the model. Three tools, no auth, in the official MCP registry as com.worthune/models.
REST API: GET /api/v1/models lists the catalog; every model serves its contract, its full spec, and a POST endpoint that validates before it computes — out-of-range requests get an error, not a quietly adjusted answer. Responses carry their spec version, assumptions, and sourced constants.
Aggregate usage is public at /api/v1/telemetry — counters only, never personal data.
The catalog — 47 Concordance-tested models
Model changes are never silent — the full version history is at /models/changelog. Before any change ships, an independent implementation written from the spec alone has to agree with the engine’s results, across 250 open test cases per model checked against textbook values — how Concordance testing works. Models are illustrative planning tools, not financial advice.