Third Rail is the front office for corporate-bond trading. QuantLib prices the book. TCA runs against TRACE prints once your FINRA feed is connected. FRED curves arrive with your FRED key. Agents run the workflows: analytics, research, and the comms layer so the desk can act, and so the book can move toward full automation when you choose.
Under it sits a ledger. No model does real work without an approved plan. Every plan, review, and certification is an append-only, hash-chained row with a sequence number and a row hash, so a third party can re-verify it. No model sits on that audit path. We write the record; the record does not let us rewrite it.
Market data sits behind one provider interface, chosen in platform config. Each feed is wired and proven when you contract for it. Run it next to what you use today, on your own hardware. You host it. Your books and venues stay yours. The trader decides until you open the gate.