Fermi

Calibrated probability estimates from natural-language questions.

Full documentation for Fermi — what it does, how to connect an MCP client, authentication, the tool surface, and worked examples — lives on the Kromatic site: kromatic.com/mcp/fermi.

Fermi also serves its own machine-readable discovery documents directly, for agents and tooling: /llms.txt, /agents.md, and /.well-known/mcp.json.

Fermi is a Kromatic product, billed per credit. See Pricing.

API Documentation

Interactive API docs (Swagger UI) — includes Authorize button for API key
API reference (ReDoc)
OpenAPI schema (JSON)

Agent Discovery Files

/llms.txt — concise overview in llmstxt.org format
/agents.md — longer quickstart with Python examples and response-schema walkthrough
/openapi.json — machine-readable OpenAPI schema
/.well-known/mcp.json — MCP endpoint descriptor
/docs — Swagger UI (interactive)

MCP Endpoints

Streamable HTTP: /mcp
SSE: /mcp/sse/
HTTP mirror: /mcp/tools → /mcp/tools/estimate

Pricing

Fermi is a paid, per-credit product. Credits cost the amount published at GET /api/v1/billing/pricing and are bought with a card through Stripe.

Try it free: anonymous callers get tier 1 only, 1 estimate per day per IP — no signup.
Sign up: POST /api/v1/accounts returns an API key and 3 starter credits.
Credit cost per estimate: tier 1 costs 1 credit, tier 2 costs 3, tier 3 costs 10.
Buy credits: call POST /api/v1/billing/checkout once in a browser to pay and save a card, then top up any time with POST /api/v1/billing/purchase-credits or the buy_credits MCP tool.

Fermi is billed separately from a kromatic.com membership. A Kromatic membership does not include Fermi credits and carries no Fermi discount.